cleanup: remove unneeded source format in read instruction

The image crate is able to infer the format, so that data is redundant

.gitignore

@@ -3,4 +3,6 @@
 /target
 .pre-commit-config.yaml
 *.pdf
-*.png
+/docs/*.png
+/testfiles/gen/*
+!/testfiles/gen/.gitkeep

CONTRIBUTING.md

@@ -14,7 +14,7 @@ Before we get started, thank you for thinking about doing so!
   - How did you install iOwO?
   - What version of iOwO are you running?
   - What operating system are you running?
-    In the case of a Linux distro, mention the specific distro and when you last update as well.
+    In the case of a Linux distro, mention the specific distro and when you last updated as well.
 - If the bug causes a crash, try to get a backtrace or in worse cases, a coredump.
 
 ### Feature requests

Cargo.lock

@@ -63,6 +63,8 @@ dependencies = [
  "ariadne",
  "clap",
  "dirs",
+ "eval",
+ "ir",
  "owo-colors",
  "ron",
  "serde",
@@ -266,12 +268,13 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a26ae43d7bcc3b814de94796a5e736d4029efb0ee900c12e2d54c993ad1a1e07"
 
 [[package]]
-name = "executor"
+name = "eval"
 version = "0.1.0"
 dependencies = [
  "clap",
  "image",
- "rpl",
+ "ir",
+ "serde",
 ]
 
 [[package]]
@@ -373,6 +376,15 @@ dependencies = [
  "tiff",
 ]
 
+[[package]]
+name = "ir"
+version = "0.1.0"
+dependencies = [
+ "either",
+ "ron",
+ "serde",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.10"
@@ -482,15 +494,6 @@ version = "4.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "caff54706df99d2a78a5a4e3455ff45448d81ef1bb63c22cd14052ca0e993a3f"
 
-[[package]]
-name = "pl-cli"
-version = "0.1.0"
-dependencies = [
- "clap",
- "executor",
- "rpl",
-]
-
 [[package]]
 name = "png"
 version = "0.17.10"
@@ -589,14 +592,6 @@ dependencies = [
  "serde_derive",
 ]
 
-[[package]]
-name = "rpl"
-version = "0.1.0"
-dependencies = [
- "ron",
- "serde",
-]
-
 [[package]]
 name = "ryu"
 version = "1.0.16"

Cargo.toml

@@ -1,20 +1,24 @@
 [workspace]
 members = [
   "crates/app",
-  "crates/executor", 
-  "crates/rpl"
+  "crates/eval",
+  "crates/ir",
 ]
 resolver = "2"
 
 [workspace.dependencies]
-clap = { version = "4", features = [ "derive" ] }
-serde = { version = "1.0", features = [ "derive" ] }
+clap = { version = "4", features = ["derive"] }
+serde = { version = "1.0", features = ["derive"] }
 
-[lints.rust]
+# to enable all the lints below, this must be present in a workspace member's Cargo.toml:
+# [lints]
+# workspace = true
+
+[workspace.lints.rust]
 unsafe_code = "deny"
 variant_size_differences = "warn"
 
-[lints.clippy]
+[workspace.lints.clippy]
 branches_sharing_code = "warn"
 clone_on_ref_ptr = "warn"
 cognitive_complexity = "warn"

LICENSE

@@ -0,0 +1,676 @@
+The main program and its libraries are licensed under the AGPL 3.0
+as listed below the separator line.
+
+Media samples in the testfiles folder are licensed under CC BY-SA 4.0.
+To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/
+The appropiate authors are given below, in the format of
+`- file/path: author (link to author)`
+
+- testfiles/rails.png: Schrottkatze (https://forge.katzen.cafe/schrottkatze)
+
+===============================================================================
+
+iOwO: media pipeline toolset
+Copyright (C) 2024  Schrottkatze, MultisampledNight and iOwO contributors
+
+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU Affero General Public License is a free, copyleft license for
+software and other kinds of works, specifically designed to ensure
+cooperation with the community in the case of network server software.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+our General Public Licenses are intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  Developers that use our General Public Licenses protect your rights
+with two steps: (1) assert copyright on the software, and (2) offer
+you this License which gives you legal permission to copy, distribute
+and/or modify the software.
+
+  A secondary benefit of defending all users' freedom is that
+improvements made in alternate versions of the program, if they
+receive widespread use, become available for other developers to
+incorporate.  Many developers of free software are heartened and
+encouraged by the resulting cooperation.  However, in the case of
+software used on network servers, this result may fail to come about.
+The GNU General Public License permits making a modified version and
+letting the public access it on a server without ever releasing its
+source code to the public.
+
+  The GNU Affero General Public License is designed specifically to
+ensure that, in such cases, the modified source code becomes available
+to the community.  It requires the operator of a network server to
+provide the source code of the modified version running there to the
+users of that server.  Therefore, public use of a modified version, on
+a publicly accessible server, gives the public access to the source
+code of the modified version.
+
+  An older license, called the Affero General Public License and
+published by Affero, was designed to accomplish similar goals.  This is
+a different license, not a version of the Affero GPL, but Affero has
+released a new version of the Affero GPL which permits relicensing under
+this license.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                       TERMS AND CONDITIONS
+
+  0. Definitions.
+
+  "This License" refers to version 3 of the GNU Affero General Public License.
+
+  "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+  "The Program" refers to any copyrightable work licensed under this
+License.  Each licensee is addressed as "you".  "Licensees" and
+"recipients" may be individuals or organizations.
+
+  To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy.  The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+  A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+  To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy.  Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+  To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies.  Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+  An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License.  If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+  1. Source Code.
+
+  The "source code" for a work means the preferred form of the work
+for making modifications to it.  "Object code" means any non-source
+form of a work.
+
+  A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+  The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form.  A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+  The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities.  However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work.  For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+  The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+  The Corresponding Source for a work in source code form is that
+same work.
+
+  2. Basic Permissions.
+
+  All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met.  This License explicitly affirms your unlimited
+permission to run the unmodified Program.  The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work.  This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+  You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force.  You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright.  Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+  Conveying under any other circumstances is permitted solely under
+the conditions stated below.  Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+  3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+  No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+  When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+  4. Conveying Verbatim Copies.
+
+  You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+  You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+  5. Conveying Modified Source Versions.
+
+  You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+    a) The work must carry prominent notices stating that you modified
+    it, and giving a relevant date.
+
+    b) The work must carry prominent notices stating that it is
+    released under this License and any conditions added under section
+    7.  This requirement modifies the requirement in section 4 to
+    "keep intact all notices".
+
+    c) You must license the entire work, as a whole, under this
+    License to anyone who comes into possession of a copy.  This
+    License will therefore apply, along with any applicable section 7
+    additional terms, to the whole of the work, and all its parts,
+    regardless of how they are packaged.  This License gives no
+    permission to license the work in any other way, but it does not
+    invalidate such permission if you have separately received it.
+
+    d) If the work has interactive user interfaces, each must display
+    Appropriate Legal Notices; however, if the Program has interactive
+    interfaces that do not display Appropriate Legal Notices, your
+    work need not make them do so.
+
+  A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit.  Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+  6. Conveying Non-Source Forms.
+
+  You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+    a) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by the
+    Corresponding Source fixed on a durable physical medium
+    customarily used for software interchange.
+
+    b) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by a
+    written offer, valid for at least three years and valid for as
+    long as you offer spare parts or customer support for that product
+    model, to give anyone who possesses the object code either (1) a
+    copy of the Corresponding Source for all the software in the
+    product that is covered by this License, on a durable physical
+    medium customarily used for software interchange, for a price no
+    more than your reasonable cost of physically performing this
+    conveying of source, or (2) access to copy the
+    Corresponding Source from a network server at no charge.
+
+    c) Convey individual copies of the object code with a copy of the
+    written offer to provide the Corresponding Source.  This
+    alternative is allowed only occasionally and noncommercially, and
+    only if you received the object code with such an offer, in accord
+    with subsection 6b.
+
+    d) Convey the object code by offering access from a designated
+    place (gratis or for a charge), and offer equivalent access to the
+    Corresponding Source in the same way through the same place at no
+    further charge.  You need not require recipients to copy the
+    Corresponding Source along with the object code.  If the place to
+    copy the object code is a network server, the Corresponding Source
+    may be on a different server (operated by you or a third party)
+    that supports equivalent copying facilities, provided you maintain
+    clear directions next to the object code saying where to find the
+    Corresponding Source.  Regardless of what server hosts the
+    Corresponding Source, you remain obligated to ensure that it is
+    available for as long as needed to satisfy these requirements.
+
+    e) Convey the object code using peer-to-peer transmission, provided
+    you inform other peers where the object code and Corresponding
+    Source of the work are being offered to the general public at no
+    charge under subsection 6d.
+
+  A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+  A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling.  In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage.  For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product.  A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+  "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source.  The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+  If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information.  But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+  The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed.  Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+  Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+  7. Additional Terms.
+
+  "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law.  If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+  When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it.  (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.)  You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+  Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+    a) Disclaiming warranty or limiting liability differently from the
+    terms of sections 15 and 16 of this License; or
+
+    b) Requiring preservation of specified reasonable legal notices or
+    author attributions in that material or in the Appropriate Legal
+    Notices displayed by works containing it; or
+
+    c) Prohibiting misrepresentation of the origin of that material, or
+    requiring that modified versions of such material be marked in
+    reasonable ways as different from the original version; or
+
+    d) Limiting the use for publicity purposes of names of licensors or
+    authors of the material; or
+
+    e) Declining to grant rights under trademark law for use of some
+    trade names, trademarks, or service marks; or
+
+    f) Requiring indemnification of licensors and authors of that
+    material by anyone who conveys the material (or modified versions of
+    it) with contractual assumptions of liability to the recipient, for
+    any liability that these contractual assumptions directly impose on
+    those licensors and authors.
+
+  All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10.  If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term.  If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+  If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+  Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+  8. Termination.
+
+  You may not propagate or modify a covered work except as expressly
+provided under this License.  Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+  However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+  Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+  Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License.  If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+  9. Acceptance Not Required for Having Copies.
+
+  You are not required to accept this License in order to receive or
+run a copy of the Program.  Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance.  However,
+nothing other than this License grants you permission to propagate or
+modify any covered work.  These actions infringe copyright if you do
+not accept this License.  Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+  10. Automatic Licensing of Downstream Recipients.
+
+  Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License.  You are not responsible
+for enforcing compliance by third parties with this License.
+
+  An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or subdividing an
+organization, or merging organizations.  If propagation of a covered
+work results from an entity transaction, each party to that
+transaction who receives a copy of the work also receives whatever
+licenses to the work the party's predecessor in interest had or could
+give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+  You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License.  For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+  11. Patents.
+
+  A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based.  The
+work thus licensed is called the contributor's "contributor version".
+
+  A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version.  For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+  Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+  In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement).  To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+  If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients.  "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+  If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License.  You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Remote Network Interaction; Use with the GNU General Public License.
+
+  Notwithstanding any other provision of this License, if you modify the
+Program, your modified version must prominently offer all users
+interacting with it remotely through a computer network (if your version
+supports such interaction) an opportunity to receive the Corresponding
+Source of your version by providing access to the Corresponding Source
+from a network server at no charge, through some standard or customary
+means of facilitating copying of software.  This Corresponding Source
+shall include the Corresponding Source for any work covered by version 3
+of the GNU General Public License that is incorporated pursuant to the
+following paragraph.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the work with which it is combined will remain governed by version
+3 of the GNU General Public License.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU Affero General Public License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU Affero General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU Affero General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU Affero General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<https://www.gnu.org/licenses/>.

crates/app/Cargo.toml

@@ -6,11 +6,16 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-clap = { workspace = true, features = [ "derive", "env" ] }
-serde = { workspace = true, features = [ "derive" ] }
-ron = "0.8"
-serde_json = "1.0"
 ariadne = "0.4"
-time = { version = "0.3", features = [ "local-offset" ] }
+clap = { workspace = true, features = [ "derive", "env" ] }
 dirs = "5"
+eval = { path = "../eval" }
+ir = { path = "../ir" }
 owo-colors = "4"
+ron = "0.8"
+serde = { workspace = true, features = [ "derive" ] }
+serde_json = "1.0"
+time = { version = "0.3", features = [ "local-offset" ] }
+
+[lints]
+workspace = true

crates/app/src/config.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::Parser;
 
 use self::{
@@ -10,6 +12,9 @@ mod config_file;
 
 /// this struct may hold all configuration
 pub struct Config {
+    pub source: PathBuf,
+    pub evaluator: eval::Available,
+
     pub startup_msg: bool,
 }
 
@@ -17,37 +22,37 @@ impl Config {
     /// Get the configs from all possible places (args, file, env...)
     pub fn read() -> Self {
         let args = Args::parse();
-        let config_path = if let Some(config_path) = args.config_path {
-            Ok(config_path)
+        let config = if let Some(config) = args.config_path {
+            Ok(config)
         } else {
             find_config_file()
         };
 
         // try to read a maybe existing config file
-        let file_config = if let Ok(config_path) = config_path {
-            let file_config = Configs::read(config_path);
-
-            match file_config {
-                Ok(c) => Some(c),
-                Err(e) => {
+        let config = config.ok().and_then(|path| {
+            Configs::read(path).map_or_else(
+                |e| {
                     eprintln!("Config error: {e:?}");
                     eprintln!("Proceeding with defaults or cli args...");
                     None
-                }
-            }
-        } else {
-            None
-        };
+                },
+                Some,
+            )
+        });
 
-        if let Some(file_config) = file_config {
+        if let Some(file) = config {
             Self {
+                source: args.source,
+                evaluator: args.evaluator.and(file.evaluator).unwrap_or_default(),
                 // this is negated because to an outward api, the negative is more intuitive,
                 // while in the source the other way around is more intuitive
-                startup_msg: !(args.no_startup_message || file_config.no_startup_message),
+                startup_msg: !(args.no_startup_message || file.no_startup_message),
             }
         } else {
             Self {
+                source: args.source,
                 startup_msg: !args.no_startup_message,
+                evaluator: args.evaluator.unwrap_or_default(),
             }
         }
     }
@@ -56,7 +61,7 @@ impl Config {
 pub mod error {
     /// Errors that can occur when reading configs
     #[derive(Debug)]
-    pub enum ConfigError {
+    pub enum Config {
         /// The config dir doesn't exist
         NoConfigDir,
         /// We didn't find a config file in the config dir
@@ -73,19 +78,19 @@ pub mod error {
         SerdeRonError(ron::error::SpannedError),
     }
 
-    impl From<std::io::Error> for ConfigError {
+    impl From<std::io::Error> for Config {
         fn from(value: std::io::Error) -> Self {
             Self::IoError(value)
         }
     }
 
-    impl From<serde_json::Error> for ConfigError {
+    impl From<serde_json::Error> for Config {
         fn from(value: serde_json::Error) -> Self {
             Self::SerdeJsonError(value)
         }
     }
 
-    impl From<ron::error::SpannedError> for ConfigError {
+    impl From<ron::error::SpannedError> for Config {
         fn from(value: ron::error::SpannedError) -> Self {
             Self::SerdeRonError(value)
         }

crates/app/src/config/cli.rs

@@ -4,6 +4,14 @@ use clap::{builder::BoolishValueParser, ArgAction, Parser};
 
 #[derive(Parser)]
 pub(crate) struct Args {
+    /// What file contains the pipeline to evaluate.
+    pub source: PathBuf,
+
+    /// How to actually run the pipeline.
+    /// Overrides the config file. Defaults to the debug evaluator.
+    #[arg(short, long)]
+    pub evaluator: Option<eval::Available>,
+
     /// Read this config file.
     #[arg(short, long)]
     pub config_path: Option<PathBuf>,

crates/app/src/config/config_file.rs

@@ -5,7 +5,7 @@ use std::{
 
 use serde::{Deserialize, Serialize};
 
-use super::error::ConfigError;
+use super::error::Config;
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct Configs {
@@ -13,6 +13,7 @@ pub struct Configs {
     pub example_value: i32,
     #[serde(default)]
     pub no_startup_message: bool,
+    pub evaluator: Option<eval::Available>,
 }
 
 /// what the fuck serde why do i need this
@@ -21,9 +22,9 @@ fn default_example_value() -> i32 {
 }
 
 /// Find the location of a config file and check if there is, in fact, a file
-pub(super) fn find_config_file() -> Result<PathBuf, ConfigError> {
+pub(super) fn find_config_file() -> Result<PathBuf, Config> {
     let Some(config_path) = dirs::config_dir() else {
-        return Err(ConfigError::NoConfigDir);
+        return Err(Config::NoConfigDir);
     };
 
     let ron_path = config_path.with_file_name("config.ron");
@@ -34,16 +35,19 @@ pub(super) fn find_config_file() -> Result<PathBuf, ConfigError> {
     } else if Path::new(&json_path).exists() {
         Ok(json_path)
     } else {
-        Err(ConfigError::NoConfigFileFound)
+        Err(Config::NoConfigFileFound)
     }
 }
 
 impl Configs {
-    pub fn read(p: PathBuf) -> Result<Self, ConfigError> {
-        match p.extension().map(|v| v.to_str().unwrap()) {
+    pub fn read(p: PathBuf) -> Result<Self, Config> {
+        match p
+            .extension()
+            .map(|v| v.to_str().expect("config path to be UTF-8"))
+        {
             Some("ron") => Ok(serde_json::from_str(&fs::read_to_string(p)?)?),
             Some("json") => Ok(ron::from_str(&fs::read_to_string(p)?)?),
-            e => Err(ConfigError::UnknownExtension(e.map(|v| v.to_owned()))),
+            e => Err(Config::UnknownExtension(e.map(str::to_owned))),
         }
     }
 }

crates/app/src/error_reporting.rs

@@ -3,12 +3,12 @@ use std::process;
 use ron::error::Position;
 
 /// Report an `Error` from the `serde_json` crate
-pub fn report_serde_json_err(src: &str, err: serde_json::Error) -> ! {
+pub fn report_serde_json_err(src: &str, err: &serde_json::Error) -> ! {
     report_serde_err(src, err.line(), err.column(), err.to_string())
 }
 
 /// Report a `SpannedError` from the `ron` crate
-pub fn report_serde_ron_err(src: &str, err: ron::error::SpannedError) -> ! {
+pub fn report_serde_ron_err(src: &str, err: &ron::error::SpannedError) -> ! {
     let Position { line, col } = err.position;
     report_serde_err(src, line, col, err.to_string())
 }
@@ -23,8 +23,8 @@ fn report_serde_err(src: &str, line: usize, col: usize, msg: String) -> ! {
         .with_message(msg)
         .with_note("We'd like to give better errors, but serde errors are horrible to work with...")
         .finish()
-        .print(("test", Source::from(src)))
-        .unwrap();
+        .eprint(("test", Source::from(src)))
+        .expect("writing error to stderr failed");
     process::exit(1);
 }
 

crates/app/src/main.rs

@@ -1,3 +1,5 @@
+use std::fs;
+
 use config::Config;
 use welcome_msg::print_startup_msg;
 
@@ -8,10 +10,18 @@ mod error_reporting;
 mod welcome_msg;
 
 fn main() {
-    // TODO: proper error handling
+    // TODO: proper error handling across the whole function
+    //       don't forget to also look inside `Config`
     let cfg = Config::read();
 
     if cfg.startup_msg {
         print_startup_msg();
     }
+
+    let source = fs::read_to_string(cfg.source).expect("can't find source file");
+    let ir = ir::from_ron(&source).expect("failed to parse source to graph ir");
+
+    let mut machine = cfg.evaluator.pick();
+    machine.feed(ir);
+    machine.eval_full();
 }

crates/eval/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "executor"
+name = "eval"
 version = "0.1.0"
 edition = "2021"
 
@@ -8,4 +8,8 @@ edition = "2021"
 [dependencies]
 clap = { workspace = true, features = [ "derive" ] }
 image = "0.24"
-rpl = { path = "../rpl" }
+ir = { path = "../ir" }
+serde = { workspace = true }
+
+[lints]
+workspace = true

crates/eval/src/kind/debug/instr/mod.rs

@@ -0,0 +1,45 @@
+pub mod read {
+    use image::{io::Reader as ImageReader, DynamicImage};
+    use ir::instruction::read::{Read, SourceType};
+
+    pub fn read(Read { source }: Read) -> DynamicImage {
+        // TODO: actual error handling
+        let img = ImageReader::open(match source {
+            SourceType::File(path) => path,
+        })
+        .expect("something went wrong :(((");
+
+        img.decode().expect("couldn't decode image")
+    }
+}
+
+pub mod write {
+    use image::{DynamicImage, ImageFormat};
+    use ir::instruction::write::{TargetFormat, TargetType, Write};
+
+    pub fn write(Write { target, format }: Write, input_data: &DynamicImage) {
+        // TODO: actual error handling
+        input_data
+            .save_with_format(
+                match target {
+                    TargetType::File(path) => path,
+                },
+                match format {
+                    TargetFormat::Jpeg => ImageFormat::Jpeg,
+                    TargetFormat::Png => ImageFormat::Png,
+                },
+            )
+            .expect("couldn't save file");
+    }
+}
+
+pub mod filters {
+    pub mod invert {
+        use image::DynamicImage;
+
+        pub fn invert(mut input_data: DynamicImage) -> DynamicImage {
+            input_data.invert();
+            input_data
+        }
+    }
+}

crates/eval/src/kind/debug/mod.rs

@@ -0,0 +1,105 @@
+use ir::{
+    id,
+    instruction::{Filter, Kind},
+    GraphIr, Instruction, Map,
+};
+
+use crate::value::Variant;
+mod instr;
+
+#[derive(Debug, Default)]
+pub struct Evaluator {
+    ir: GraphIr,
+
+    /// What the output of each individual streamer, and as result its output sockets, is.
+    /// Grows larger as evaluation continues,
+    /// as there's no mechanism for purging never-to-be-used-anymore instructions yet.
+    evaluated: Map<id::Output, Variant>,
+}
+
+impl crate::Evaluator for Evaluator {
+    fn feed(&mut self, ir: GraphIr) {
+        self.ir = ir;
+        self.evaluated.clear();
+    }
+
+    fn eval_full(&mut self) {
+        // GraphIr::topological_sort returns InstructionRefs, which are mostly cool
+        // but we'd like to have them owned, so we can call Self::step without lifetime hassle
+        let queue: Vec<Instruction> = self
+            .ir
+            .topological_sort()
+            .into_iter()
+            .map(Into::into)
+            .collect();
+
+        for instr in queue {
+            self.step(instr);
+        }
+    }
+}
+
+impl Evaluator {
+    #[allow(clippy::needless_pass_by_value)]
+    fn step(&mut self, instr: Instruction) {
+        // what inputs does this instr need? fetch them
+        let inputs: Vec<_> = instr
+            .input_sources()
+            .iter()
+            .map(|source| {
+                let source_socket = source
+                    .as_ref()
+                    .expect("all inputs to be connected when an instruction is ran");
+                self.evaluated
+                    .get(source_socket)
+                    .expect("toposort to yield later instrs only after previous ones")
+            })
+            .collect();
+
+        // then actually do whatever the instruction should do
+        // NOTE: makes heavy use of index slicing,
+        // on the basis that ir::instruction::Kind::socket_count is correct
+        // TODO: make this a more flexible dispatch-ish arch
+        let output = match instr.kind {
+            Kind::Read(details) => Some(Variant::Image(instr::read::read(details))),
+            Kind::Write(details) => {
+                #[allow(irrefutable_let_patterns)] // will necessarily change
+                let Variant::Image(input) = inputs[0] else {
+                    panic!("cannot only write images, but received: `{:?}`", inputs[0]);
+                };
+                instr::write::write(details, input);
+                None
+            }
+            Kind::Math(_) => todo!(),
+            Kind::Blend(_) => todo!(),
+            Kind::Noise(_) => todo!(),
+            Kind::Filter(filter_instruction) => match filter_instruction {
+                Filter::Invert => {
+                    #[allow(irrefutable_let_patterns)]
+                    let Variant::Image(input) = inputs[0] else {
+                        panic!(
+                            "cannot only filter invert images, but received: `{:?}`",
+                            inputs[0]
+                        );
+                    };
+
+                    Some(Variant::Image(instr::filters::invert::invert(
+                        input.clone(),
+                    )))
+                }
+            },
+        };
+
+        if let Some(output) = output {
+            // TODO: very inaccurate, actually respect individual instructions.
+            //       should be implied by a different arch
+            // TODO: all of those should not be public, offer some methods to get this on
+            //       `Instruction` instead (can infer short-term based on Kind::socket_count)
+            let socket = id::Output(id::Socket {
+                belongs_to: instr.id,
+                idx: id::SocketIdx(0),
+            });
+            self.evaluated.insert(socket, output);
+        }
+    }
+}

crates/eval/src/kind/mod.rs

@@ -0,0 +1 @@
+pub mod debug;

crates/eval/src/lib.rs

@@ -0,0 +1,43 @@
+use ir::GraphIr;
+
+mod kind;
+mod value;
+
+/// Can collapse a [`GraphIr`] in meaningful ways and do interesting work on it.
+///
+/// It's surprisingly difficult to find a fitting description for this.
+pub trait Evaluator {
+    /// Take some [`GraphIr`] which will then be processed later.
+    /// May be called multiple times, in which the [`GraphIr`]s should add up.
+    // TODO: atm they definitely don't add up -- add some functionality to GraphIr to
+    //       make it combine two graphs into one
+    fn feed(&mut self, ir: GraphIr);
+
+    /// Walk through the _whole_ [`GraphIr`] and run through each instruction.
+    fn eval_full(&mut self);
+
+    // TODO: for an LSP or the like, eval_single which starts at a given instr
+}
+
+/// The available [`Evaluator`]s.
+///
+/// Checklist for adding new ones:
+///
+/// 1. Create a new module under the [`kind`] module.
+/// 2. Add a struct and implement [`Evaluator`] for it.
+#[derive(Clone, Copy, Debug, Default, clap::ValueEnum, serde::Deserialize, serde::Serialize)]
+pub enum Available {
+    /// Runs fully on the CPU. Single-threaded, debug-friendly and quick to implement.
+    #[default]
+    Debug,
+}
+
+impl Available {
+    /// Selects the [`Evaluator`] corresponding to this label.
+    #[must_use]
+    pub fn pick(&self) -> Box<dyn Evaluator> {
+        match self {
+            Self::Debug => Box::new(kind::debug::Evaluator::default()),
+        }
+    }
+}

crates/eval/src/value/mod.rs

@@ -0,0 +1,12 @@
+use image::DynamicImage;
+
+/// Any runtime value that an instruction can input or output.
+///
+/// The name is taken from [Godot's `Variant` type],
+/// which is very similar to this one.
+///
+/// [Godot's `Variant` type]: https://docs.godotengine.org/en/stable/classes/class_variant.html
+#[derive(Clone, Debug)]
+pub enum Variant {
+    Image(DynamicImage),
+}

crates/executor/src/cpu/mod.rs

@@ -1 +0,0 @@
-pub(crate) struct CpuExecutor;

crates/executor/src/debug/instructions/mod.rs

@@ -1,41 +0,0 @@
-pub mod read {
-    use image::{io::Reader as ImageReader, DynamicImage};
-    use rpl::instructions::read::{Read, SourceType};
-
-    pub fn read(Read { source, format }: Read) -> DynamicImage {
-        let mut img = ImageReader::open(match source {
-            SourceType::File(path) => path,
-        })
-        .expect("something went wrong :(((");
-
-        img.decode().expect("couldn't decode image")
-    }
-}
-
-pub mod write {
-    use image::{io::Reader as ImageReader, DynamicImage, ImageFormat};
-    use rpl::instructions::write::{TargetFormat, TargetType, Write};
-
-    pub fn write(Write { target, format }: Write, input_data: DynamicImage) {
-        input_data.save_with_format(
-            match target {
-                TargetType::File(path) => path,
-            },
-            match format {
-                TargetFormat::Jpeg => ImageFormat::Jpeg,
-                TargetFormat::Png => ImageFormat::Png,
-            },
-        );
-    }
-}
-
-pub mod filters {
-    pub mod invert {
-        use image::DynamicImage;
-
-        pub fn invert(mut input_data: DynamicImage) -> DynamicImage {
-            input_data.invert();
-            input_data
-        }
-    }
-}

crates/executor/src/debug/mod.rs

@@ -1,37 +0,0 @@
-use rpl::instructions::{FilterInstruction, Instruction};
-
-use crate::{value::DynamicValue, Executor};
-mod instructions;
-
-pub struct DebugExecutor;
-
-impl Executor for DebugExecutor {
-    fn execute(instruction: Instruction, input: Option<DynamicValue>) -> Option<DynamicValue> {
-        match instruction {
-            Instruction::Read(read_instruction) => Some(DynamicValue::Image(
-                instructions::read::read(read_instruction),
-            )),
-            Instruction::Write(write_instruction) => {
-                instructions::write::write(
-                    write_instruction,
-                    match input {
-                        Some(DynamicValue::Image(img)) => img,
-                        _ => panic!("awawwawwa"),
-                    },
-                );
-                None
-            }
-            Instruction::Math(_) => todo!(),
-            Instruction::Blend(_) => todo!(),
-            Instruction::Noise(_) => todo!(),
-            Instruction::Filter(filter_instruction) => match filter_instruction {
-                FilterInstruction::Invert => Some(DynamicValue::Image(
-                    instructions::filters::invert::invert(match input {
-                        Some(DynamicValue::Image(img)) => img,
-                        _ => panic!("invalid value type for invert"),
-                    }),
-                )),
-            },
-        }
-    }
-}

crates/executor/src/lib.rs

@@ -1,38 +0,0 @@
-use rpl::instructions::Instruction;
-use value::DynamicValue;
-
-mod debug;
-mod value;
-
-/// The available executors
-/// unused in early dev.
-#[derive(Debug, Clone, Copy, clap::ValueEnum)]
-pub enum Executors {
-    /// the debug executor is single threaded and really, *really* slow. And unstable. Don't use. Unless you're a dev working on this.
-    Debug,
-    /// the CPU executor primarily uses the CPU. Most likely most feature complete, and the fallback.
-    Cpu,
-    /// the Vulkan executor (obviously) uses vulkan. there's a good chance this isn't implemented yet as you're reading this.
-    Vulkan,
-}
-
-trait Executor {
-    fn execute(instruction: Instruction, input: Option<DynamicValue>) -> Option<DynamicValue>;
-}
-
-pub fn execute_all(instructions: Vec<Instruction>) {
-    let mut tmp = None;
-
-    for instruction in instructions {
-        tmp = debug::DebugExecutor::execute(instruction, tmp);
-    }
-}
-
-// scratchpad lol:
-// execution structure:
-// 1. take in rpl
-// 2. analyse/validate structure against allowed executors
-// 3. assign executors to instructions
-// 4. optimize
-// 5. prepare memory management patterns
-// 6. run

crates/executor/src/value/mod.rs

@@ -1,5 +0,0 @@
-use image::DynamicImage;
-
-pub enum DynamicValue {
-    Image(DynamicImage),
-}

crates/ir/Cargo.toml

@@ -1,10 +1,14 @@
 [package]
-name = "rpl"
+name = "ir"
 version = "0.1.0"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-serde = { workspace = true, features = [ "derive" ] }
+either = "1.9"
 ron = "0.8"
+serde = { version = "1.0.193", features = ["derive"] }
+
+[lints]
+workspace = true

crates/ir/src/id.rs

@@ -0,0 +1,84 @@
+//! Instance identification for instructions and their glue.
+//!
+//! Instructions as defined in [`crate::instruction::Kind`] and descendants are very useful,
+//! but they cannot be directly used as vertices in the graph IR,
+//! as there may easily be multiple instructions of the same kind in the same program.
+//!
+//! Instead, this module offers an alternative way to refer to specific instances:
+//!
+//! - [`Instruction`]s are effectively just a number floating in space,
+//!   incremented each time a new instruction is referred to.
+//! - [`Socket`]s contain
+//!   - what [`Instruction`] they belong to
+//!   - which index they occupy on it
+//!
+//!   The distinction between [`Input`] and [`Output`] is implemented
+//!   as them being different types.
+
+use std::fmt;
+
+use serde::{Deserialize, Serialize};
+
+/// One specific instruction.
+///
+/// It does **not** contain what kind of instruction this is.
+/// Refer to [`crate::instruction::Kind`] for this instead.
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct Instruction(pub(super) u64);
+
+impl fmt::Debug for Instruction {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "InstrId {}", self.0)
+    }
+}
+
+/// On an **instruction**, accepts incoming data.
+///
+/// An **instruction** cannot run if any of these are not connected.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct Input(pub(super) Socket);
+
+impl Input {
+    #[must_use]
+    pub fn socket(&self) -> &Socket {
+        &self.0
+    }
+}
+
+/// On an **instruction**, returns outgoing data to be fed to [`Input`]s.
+///
+/// In contrast to [`Input`]s, [`Output`]s may be used or unused.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct Output(pub Socket); // TODO: Restrict publicness to super
+
+impl Output {
+    #[must_use]
+    pub fn socket(&self) -> &Socket {
+        &self.0
+    }
+}
+
+/// An unspecified socket on a specific **instruction**,
+/// and where it is on that **instruction**.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct Socket {
+    pub belongs_to: Instruction,
+    pub idx: SocketIdx,
+}
+
+/// Where a [`Socket`] is on one **instruction**.
+///
+/// Note that this does **not** identify a [`Socket`] globally.
+/// There may be multiple [`Socket`]s sharing the same [`SocketIdx`],
+/// but on different [`Instruction`]s.
+///
+/// This really only serves for denoting where a socket is,
+/// when it's already clear which instruction is referred to.
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct SocketIdx(pub u16); // TODO: Restrict publicness to super
+
+impl fmt::Debug for SocketIdx {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}

crates/ir/src/instruction/mod.rs

@@ -0,0 +1,81 @@
+use serde::{Deserialize, Serialize};
+
+pub mod read;
+pub mod write;
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub enum Kind {
+    // TODO: `read::Read` and `write::Write` hold real values atm -- they should actually
+    //       point to `Const` instructions instead (which are... yet to be done...)
+    Read(read::Read),
+    Write(write::Write),
+    Math(Math),
+    Blend(Blend),
+    Noise(Noise),
+    Filter(Filter),
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub enum Math {
+    Add,
+    Subtract,
+    Multiply,
+    Divide,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub enum Blend {
+    Normal,
+    Multiply,
+    Additive,
+    Overlay,
+    Screen,
+    Subtractive,
+    Difference,
+    Darken,
+    Lighten,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub enum Noise {
+    Perlin,
+    Simplex,
+    Voronoi,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub enum Filter {
+    Invert,
+}
+
+// TODO: given that this basically matches on all instructions, we may need to use
+//       the visitor pattern in future here, or at least get them behind traits
+//       which should allow far more nuanced description
+impl Kind {
+    /// Returns how many sockets this kind of instruction has.
+    #[must_use]
+    pub fn socket_count(&self) -> SocketCount {
+        match self {
+            Self::Read(_) => (0, 1),
+            Self::Write(_) => (1, 0),
+            Self::Math(_) | Self::Blend(_) => (2, 1),
+            Self::Noise(_) => {
+                todo!("how many arguments does noise take? how many outputs does it have?")
+            }
+            Self::Filter(Filter::Invert) => (1, 1),
+        }
+        .into()
+    }
+}
+
+/// How many sockets are on an instruction?
+pub struct SocketCount {
+    pub inputs: u16,
+    pub outputs: u16,
+}
+
+impl From<(u16, u16)> for SocketCount {
+    fn from((inputs, outputs): (u16, u16)) -> Self {
+        Self { inputs, outputs }
+    }
+}

crates/ir/src/instruction/read.rs

@@ -0,0 +1,12 @@
+use serde::{Deserialize, Serialize};
+use std::path::PathBuf;
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct Read {
+    pub source: SourceType,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub enum SourceType {
+    File(PathBuf),
+}

crates/ir/src/instruction/write.rs

@@ -0,0 +1,19 @@
+use serde::{Deserialize, Serialize};
+use std::path::PathBuf;
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct Write {
+    pub target: TargetType,
+    pub format: TargetFormat,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub enum TargetType {
+    File(PathBuf),
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub enum TargetFormat {
+    Jpeg,
+    Png,
+}

crates/ir/src/lib.rs

@@ -0,0 +1,353 @@
+use std::num::NonZeroUsize;
+
+use instruction::SocketCount;
+use serde::{Deserialize, Serialize};
+
+pub mod id;
+pub mod instruction;
+pub mod semi_human;
+
+pub type Map<K, V> = std::collections::BTreeMap<K, V>;
+pub type Set<T> = std::collections::BTreeSet<T>;
+
+/// Gives you a super well typed graph IR for a given human-readable repr.
+///
+/// Look at [`semi_human::GraphIr`] and the test files in the repo at `testfiles/`
+/// to see what the RON should look like.
+/// No, we don't want you to write out [`GraphIr`] in full by hand.
+/// That's something for the machines to do.
+///
+/// # Errors
+///
+/// Returns an error if the parsed source is not a valid human-readable graph IR.
+pub fn from_ron(source: &str) -> ron::error::SpannedResult<GraphIr> {
+    let human_repr: semi_human::GraphIr = ron::from_str(source)?;
+    Ok(human_repr.into())
+}
+
+/// The toplevel representation of a whole pipeline.
+///
+/// # DAGs
+///
+/// Pipelines may not be fully linear. They may branch out and recombine later on.
+/// As such, the representation for them which is currently used is a
+/// [**D**irected **A**cyclic **G**raph](https://en.wikipedia.org/wiki/Directed_acyclic_graph).
+///
+/// For those who are already familiar with graphs, a DAG is one, except that:
+///
+/// - It is **directed**: Edges have a direction they point to.
+///   In this case, edges point from the outputs of streamers to inputs of consumers.
+/// - It is **acyclic**: Those directed edges may not form loops.
+///   In other words, if one follows edges only in their direction, it must be impossible
+///   to come back to an already visited node.
+///
+/// Here, if an edge points from _A_ to _B_ (`A --> B`),
+/// then _A_ is called a **dependency** or an **input source** of _B_,
+/// and _B_ is called a **dependent** or an **output target** of _A_.
+///
+/// The DAG also enables another neat operation:
+/// [Topological sorting](https://en.wikipedia.org/wiki/Topological_sorting).
+/// This allows to put the entire graph into a linear list,
+/// where it's guaranteed that once a vertex is visited,
+/// all dependencies of it will have been visited already as well.
+///
+/// The representation used here in specific is a bit more complicated,
+/// since **instructions** directly aren't just connected to one another,
+/// but their **sockets** are instead.
+///
+/// So the vertices of the DAG are the **sockets**
+/// (which are either [`id::Input`] or [`id::Output`] depending on the direction),
+/// and each **socket** in turn belongs to an **instruction**.
+///
+/// # Usage
+///
+/// - If you want to build one from scratch,
+///   add a few helper methods like
+///     constructing an empty one,
+///     adding instructions and
+///     adding edges
+/// - If you want to construct one from an existing repr,
+///   maybe you want to use [`semi_human::GraphIr`].
+///
+/// # Storing additional data
+///
+/// Chances are the graph IR seems somewhat fit to put metadata in it.
+/// However, most likely you're interacting in context of some other system,
+/// and also want to manage and index that data on your own.
+///
+/// As such, consider using _secondary_ maps instead.
+/// That is, store in a data structure _you_ own a mapping
+/// from [`id`]s
+/// to whatever data you need.
+#[derive(Clone, Debug, Default, PartialEq, Eq, Deserialize, Serialize)]
+pub struct GraphIr {
+    /// "Backbone" storage of all **instruction** IDs to
+    /// what **kind of instruction** they are.
+    instructions: Map<id::Instruction, instruction::Kind>,
+
+    /// How the data flows forward. **Dependencies** map to **dependents** here.
+    edges: Map<id::Output, Set<id::Input>>,
+    /// How the data flows backward. **Dependents** map to **dependencies** here.
+    rev_edges: Map<id::Input, id::Output>,
+}
+
+// TODO: this impl block, but actually the whole module, screams for tests
+impl GraphIr {
+    /// Look "backwards" in the graph,
+    /// and find out what instructions need to be done before this one.
+    /// The input slots are visited in order.
+    ///
+    /// - The iterator returns individually [`Some`]`(`[`None`]`)` if the corresponding slot is
+    ///   not connected.
+    ///
+    /// The same caveats as for [`GraphIr::resolve`] apply.
+    #[must_use]
+    pub fn input_sources(
+        &self,
+        subject: &id::Instruction,
+    ) -> Option<impl Iterator<Item = Option<&id::Output>> + '_> {
+        let (subject, kind) = self.instructions.get_key_value(subject)?;
+        let SocketCount { inputs, .. } = kind.socket_count();
+
+        Some((0..inputs).map(|idx| {
+            let input = id::Input(socket(subject, idx));
+            self.rev_edges.get(&input)
+        }))
+    }
+
+    /// Look "forwards" in the graph to see what other instructions this instruction feeds into.
+    ///
+    /// The output slots represent the top-level iterator,
+    /// and each one's connections are emitted one level below.
+    ///
+    /// Just [`Iterator::flatten`] if you are not interested in the slots.
+    ///
+    /// The same caveats as for [`GraphIr::resolve`] apply.
+    #[must_use]
+    pub fn output_targets(
+        &self,
+        subject: &id::Instruction,
+    ) -> Option<impl Iterator<Item = Option<&Set<id::Input>>> + '_> {
+        let (subject, kind) = self.instructions.get_key_value(subject)?;
+        let SocketCount { outputs, .. } = kind.socket_count();
+
+        Some((0..outputs).map(|idx| {
+            let output = id::Output(socket(subject, idx));
+            self.edges.get(&output)
+        }))
+    }
+
+    /// Returns the instruction corresponding to the given ID.
+    /// Returns [`None`] if there is no such instruction in this graph IR.
+    ///
+    /// Theoretically this could be fixed easily at the expense of some memory
+    /// by just incrementing and storing some global counter,
+    /// however, at the moment there's no compelling reason
+    /// to actually have multiple [`GraphIr`]s at one point in time.
+    /// Open an issue if that poses a problem for you.
+    #[must_use]
+    pub fn resolve<'ir>(&'ir self, subject: &id::Instruction) -> Option<InstructionRef<'ir>> {
+        let (id, kind) = self.instructions.get_key_value(subject)?;
+
+        let input_sources = self.input_sources(subject)?.collect();
+        let output_targets = self.output_targets(subject)?.collect();
+
+        Some(InstructionRef {
+            id,
+            kind,
+            input_sources,
+            output_targets,
+        })
+    }
+
+    /// Returns the instruction this input belongs to.
+    ///
+    /// The same caveats as for [`GraphIr::resolve`] apply.
+    #[must_use]
+    pub fn owner_of_input<'ir>(&'ir self, input: &id::Input) -> Option<InstructionRef<'ir>> {
+        self.resolve(&input.socket().belongs_to)
+    }
+
+    /// Returns the instruction this output belongs to.
+    ///
+    /// The same caveats as for [`GraphIr::resolve`] apply.
+    #[must_use]
+    pub fn owner_of_output<'ir>(&'ir self, output: &id::Output) -> Option<InstructionRef<'ir>> {
+        self.resolve(&output.socket().belongs_to)
+    }
+
+    /// Returns the order in which the instructions could be visited
+    /// in order to ensure that all dependencies are resolved
+    /// before a vertex is visited.
+    ///
+    /// # Panics
+    ///
+    /// Panics if there are any cycles in the IR, as it needs to be a DAG.
+    #[must_use]
+    // yes, this function could probably return an iterator and be lazy
+    // no, not today
+    pub fn topological_sort(&self) -> Vec<InstructionRef> {
+        // count how many incoming edges each vertex has
+        let mut nonzero_input_counts: Map<_, NonZeroUsize> =
+            self.rev_edges
+                .iter()
+                .fold(Map::new(), |mut count, (input, _)| {
+                    let _ = *count
+                        .entry(input.socket().belongs_to.clone())
+                        .and_modify(|count| *count = count.saturating_add(1))
+                        .or_insert(NonZeroUsize::MIN);
+                    count
+                });
+
+        // are there any unconnected ones we could start with?
+        // TODO: experiment if a VecDeque with some ordering fun is digested better by the executor
+        let no_inputs: Vec<_> = {
+            let nonzero: Set<_> = nonzero_input_counts.keys().collect();
+            let all: Set<_> = self.instructions.keys().collect();
+            all.difference(&nonzero).copied().cloned().collect()
+        };
+
+        // then let's find the order!
+        let mut order = Vec::new();
+        let mut active_queue = no_inputs;
+
+        while let Some(current) = active_queue.pop() {
+            // now that this vertex is visited and resolved,
+            // make sure all dependents notice that
+
+            let dependents = self
+                .output_targets(&current)
+                .expect("graph to be consistent")
+                .flatten()
+                .flatten();
+
+            for dependent_input in dependents {
+                let dependent = &dependent_input.socket().belongs_to;
+
+                // how many inputs are connected to this dependent without us?
+                let count = nonzero_input_counts
+                    .get_mut(dependent)
+                    .expect("connected output must refer to non-zero input");
+
+                let new = NonZeroUsize::new(count.get() - 1);
+                if let Some(new) = new {
+                    // aww, still some
+                    *count = new;
+                    continue;
+                }
+
+                // none, that means this one is free now! let's throw it onto the active queue then
+                let (now_active, _) = nonzero_input_counts
+                    .remove_entry(dependent)
+                    .expect("connected output must refer to non-zero input");
+                active_queue.push(now_active);
+            }
+
+            // TODO: check if this instruction is "well-fed", that is, has all the inputs it needs,
+            //       and if not, panic
+            order.push(self.resolve(&current).expect("graph to be consistent"));
+        }
+
+        assert!(
+            nonzero_input_counts.is_empty(),
+            concat!(
+                "topological sort didn't cover all instructions\n",
+                "either there are unconnected inputs, or there is a cycle\n",
+                "unresolved instructions:\n",
+                "{:#?}"
+            ),
+            nonzero_input_counts,
+        );
+
+        order
+    }
+}
+
+/// Constructs an [`id::Socket`] a bit more tersely.
+fn socket(id: &id::Instruction, idx: u16) -> id::Socket {
+    id::Socket {
+        belongs_to: id.clone(),
+        idx: id::SocketIdx(idx),
+    }
+}
+
+/// A full instruction bundeled in context, with its inputs and outputs.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Instruction {
+    pub id: id::Instruction,
+    pub kind: instruction::Kind,
+
+    // can't have these two public since then a user might corrupt their length
+    input_sources: Vec<Option<id::Output>>,
+    output_targets: Vec<Set<id::Input>>,
+}
+
+impl Instruction {
+    /// Where this instruction gets its inputs from.
+    ///
+    /// [`None`] means that this input is unfilled,
+    /// and must be filled before the instruction can be ran.
+    #[must_use]
+    pub fn input_sources(&self) -> &[Option<id::Output>] {
+        &self.input_sources
+    }
+
+    /// To whom outputs are sent.
+    #[must_use]
+    pub fn output_targets(&self) -> &[Set<id::Input>] {
+        &self.output_targets
+    }
+}
+
+/// [`Instruction`], but every single field is borrowed instead.
+/// See its docs.
+///
+/// Use the [`From`] impl to handily convert into an [`Instruction`].
+/// The other way around is unlikely to be wanted — since you already have an [`Instruction`],
+/// chances are you just want to take a reference (`&`) of it.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct InstructionRef<'ir> {
+    pub id: &'ir id::Instruction,
+    pub kind: &'ir instruction::Kind,
+
+    input_sources: Vec<Option<&'ir id::Output>>,
+    output_targets: Vec<Option<&'ir Set<id::Input>>>,
+}
+
+impl<'ir> InstructionRef<'ir> {
+    /// Where this instruction gets its inputs from.
+    ///
+    /// [`None`] means that this input is unfilled,
+    /// and must be filled before the instruction can be ran.
+    #[must_use]
+    pub fn input_sources(&self) -> &[Option<&'ir id::Output>] {
+        &self.input_sources
+    }
+
+    /// To whom outputs are sent.
+    #[must_use]
+    pub fn output_targets(&self) -> &[Option<&'ir Set<id::Input>>] {
+        &self.output_targets
+    }
+}
+
+// would love to use ToOwned but Rust has no specialization yet
+// and it'd hurt a blanket impl of ToOwned otherwise
+impl From<InstructionRef<'_>> for Instruction {
+    fn from(source: InstructionRef<'_>) -> Self {
+        Self {
+            id: source.id.clone(),
+            kind: source.kind.clone(),
+            input_sources: source
+                .input_sources
+                .into_iter()
+                .map(Option::<&_>::cloned)
+                .collect(),
+            output_targets: source
+                .output_targets
+                .into_iter()
+                .map(|outputs| outputs.map(Clone::clone).unwrap_or_default())
+                .collect(),
+        }
+    }
+}

crates/ir/src/semi_human.rs

@@ -0,0 +1,87 @@
+//! The midterm solution for source representation, until we've got a nice source frontend.
+//!
+//! Sacrifices type expressivity for the sake of typability in [RON] files.
+//!
+//! **If you want to construct a graph IR programmatically,
+//! use [`crate::GraphIr`] directly instead,
+//! as it gives you more control to specify where your instructions came from.**
+//!
+//! [RON]: https://docs.rs/ron/latest/ron/
+
+use serde::{Deserialize, Serialize};
+
+use crate::{id, instruction, Map, Set};
+
+/// Semi-human-{read,writ}able [`crate::GraphIr`] with far less useful types.
+///
+/// **Do not use this if you want to programatically construct IR.**
+/// Instead, directly use [`crate::GraphIr`].
+#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize)]
+pub struct GraphIr {
+    /// See [`crate::GraphIr::instructions`], just that a simple number is used for the ID instead
+    pub(crate) instructions: Map<u64, instruction::Kind>,
+    /// See [`crate::GraphIr::edges`], the forward edges.
+    /// RON wants you to type the set as if it were a list.
+    pub(crate) edges: Map<Socket, Set<Socket>>,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Deserialize, Serialize)]
+pub struct Socket {
+    /// ID of the instruction this socket is on.
+    pub(crate) on: u64,
+    pub(crate) idx: u16,
+}
+
+impl From<Socket> for id::Socket {
+    fn from(source: Socket) -> Self {
+        Self {
+            belongs_to: id::Instruction(source.on),
+            idx: id::SocketIdx(source.idx),
+        }
+    }
+}
+
+impl From<GraphIr> for crate::GraphIr {
+    fn from(source: GraphIr) -> Self {
+        let edges = source.edges.clone();
+        Self {
+            instructions: source
+                .instructions
+                .into_iter()
+                .map(|(id, kind)| (id::Instruction(id), kind))
+                .collect(),
+            edges: type_edges(source.edges),
+            rev_edges: reverse_and_type_edges(edges),
+        }
+    }
+}
+
+fn type_edges(edges: Map<Socket, Set<Socket>>) -> Map<id::Output, Set<id::Input>> {
+    edges
+        .into_iter()
+        .map(|(output, inputs)| {
+            let output = id::Output(output.into());
+            let inputs = inputs.into_iter().map(Into::into).map(id::Input).collect();
+            (output, inputs)
+        })
+        .collect()
+}
+
+fn reverse_and_type_edges(edges: Map<Socket, Set<Socket>>) -> Map<id::Input, id::Output> {
+    edges
+        .into_iter()
+        .fold(Map::new(), |mut rev_edges, (output, inputs)| {
+            let output = id::Output(output.into());
+
+            for input in inputs {
+                let input = id::Input(input.into());
+                let previous = rev_edges.insert(input, output.clone());
+                if let Some(previous) = previous {
+                    // TODO: handle this with a TryFrom impl
+                    panic!("two or more outputs referred to the same input {previous:#?}");
+                }
+            }
+
+            rev_edges
+        })
+}

crates/rpl/src/instructions/mod.rs

@@ -1,47 +0,0 @@
-use serde::{Deserialize, Serialize};
-
-pub mod read;
-pub mod write;
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum Instruction {
-    Read(read::Read),
-    Write(write::Write),
-    Math(MathInstruction),
-    Blend(BlendInstruction),
-    Noise(NoiseInstruction),
-    Filter(FilterInstruction),
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum MathInstruction {
-    Add,
-    Subtract,
-    Multiply,
-    Divide,
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum BlendInstruction {
-    Normal,
-    Multiply,
-    Additive,
-    Overlay,
-    Screen,
-    Subtractive,
-    Difference,
-    Darken,
-    Lighten,
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum NoiseInstruction {
-    Perlin,
-    Simplex,
-    Voronoi,
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum FilterInstruction {
-    Invert,
-}

crates/rpl/src/instructions/read.rs

@@ -1,19 +0,0 @@
-use serde::{Deserialize, Serialize};
-use std::path::PathBuf;
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub struct Read {
-    pub source: SourceType,
-    pub format: SourceFormat,
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum SourceType {
-    File(PathBuf),
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum SourceFormat {
-    Jpeg,
-    Png,
-}

crates/rpl/src/instructions/write.rs

@@ -1,19 +0,0 @@
-use serde::{Deserialize, Serialize};
-use std::path::PathBuf;
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub struct Write {
-    pub target: TargetType,
-    pub format: TargetFormat,
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum TargetType {
-    File(PathBuf),
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub enum TargetFormat {
-    Jpeg,
-    Png,
-}

crates/rpl/src/lib.rs

@@ -1,38 +0,0 @@
-use instructions::Instruction;
-use serde::{Deserialize, Serialize};
-
-use crate::instructions::{
-    read::{SourceFormat, SourceType},
-    write::{TargetFormat, TargetType},
-    MathInstruction,
-};
-
-pub mod instructions;
-
-pub fn from_ron(raw: &str) -> Rpl {
-    ron::from_str(raw).unwrap()
-}
-
-#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
-pub struct Rpl(pub Vec<Instruction>);
-
-#[test]
-fn test_simple_deserialize() {
-    const TEST_DATA: &str =
-        "([Read( (source: File(\"~/example/file.png\"), format: Png) ),Math(Add),Write(( target: File(\"~/example/out.jpg\"), format: Jpeg))])";
-
-    assert_eq!(
-        from_ron(TEST_DATA),
-        Rpl(vec![
-            Instruction::Read(instructions::read::Read {
-                source: SourceType::File("~/example/file.png".into()),
-                format: SourceFormat::Png
-            }),
-            Instruction::Math(MathInstruction::Add),
-            Instruction::Write(instructions::write::Write {
-                target: TargetType::File("~/example/out.jpg".into()),
-                format: TargetFormat::Jpeg
-            })
-        ])
-    );
-}

crates/rpl/src/value/mod.rs

@@ -1,3 +0,0 @@
-pub enum DynamicValue {
-    Image(DynamicImage),
-}

docs/design/iowo-design.typ

@@ -7,7 +7,75 @@
   subtitle: [don't worry, we're just dreaming],
 )
 
-= Evaluation stages
+= Term overview
+
+/ Processing stages:
+  Whole workflow of iOwO,
+  from the source to evaluation.
+
+/ Source:
+  Nice textual representation of what iOwO is supposed to do.
+  Consists of instructions and pipelines.
+
+/ Graph IR:
+  Intermediate machine-readable representation of the source.
+  Can be modified by the optimizer
+  and is evaluated or "ran" by the runtime.
+
+/ Optimizer:
+  Simplifies the graph IR and makes it faster to run.
+
+/ Runtime:
+  All-encompassing term for what's done
+  after a graph IR is optimized and fully ready to go.
+
+/ Scheduler:
+  Looks at the graph IR
+  and decides which evaluator gets to run which part of it.
+
+/ Evaluator:
+  One specific implementation of how to run
+  through the whole graph IR to get its results.
+
+/ Function:
+  On the source level and before the graph IR,
+  anything that can be run with inputs,
+  possibly receiving outputs.
+
+/ Instruction:
+  Function, but in the graph IR and at runtime.
+  Ask schrottkatze on why the differentiation is important.
+
+/ Input:
+  Received by a function or instruction.
+  Different inputs may result in different behavior
+  and/or in different outputs.
+
+/ Argument:
+  On the source level,
+  an input which is given ad-hoc
+  instead of provided through a pipeline.
+
+/ Output:
+  Returned by a function or instruction,
+  and can be fed into other functions or instructions.
+
+/ Consumer:
+  Function or instruction that takes at least 1 input.
+
+/ Streamer:
+  Function or instruction that returns at least 1 output.
+
+/ Modifier:
+  Function or instruction that is _both_ a consumer and a streamer.
+
+/ Pipeline:
+  Any chain of streamers and consumers,
+  possibly with modifiers in-between,
+  that may branch out
+  and recombine arbitrarily.
+
+= Processing stages
 
 #graphics.stages-overview
 
@@ -18,7 +86,7 @@ This has a number of benefits and implications:
 - Bugs are easier to trace down to one stage.
 - Stages are also replacable, pluggable and usable somewhere else.
   - For example,
-    one could write a Just-In-Time compiler as a new executor to replace the runtime stage,
+    one could write a Just-In-Time compiler as a new evaluator to replace the runtime stage,
     while preserving the source #arrow() graph IR step.
 
 However, this also makes the architecture somewhat more complicated. So here we try our best to describe how each stage looks like. If you have any feedback, feel free to drop it on #link("https://forge.katzen.cafe/katzen-cafe/iowo/issues")[the issues in the repository]!
@@ -152,17 +220,17 @@ Merges and simplifies functions in the graph IR.
 == Runtime <runtime>
 
 Runs through all functions in the graph IR.
-It does not have any significantly other representation,
+It does not have any significantly different representation,
 and despite its name there's _no_ bytecode involved.
 
-Different runtimes are called executors.
-Executors operate on instructions instead of functions.
-
 === Scheduler
 
-Looks at the graph IR and decides when the VM should execute what.
+Looks at the graph IR and decides when which evaluator gets to evaluate what.
 
-=== VM <vm>
+=== Evaluator
+
+Runs instructions given to it in a specific way,
+such as for example on the GPU using OpenCL.
 
 = Open questions
 

docs/design/util/graphics.typ

@@ -219,8 +219,11 @@
   )
 }
 
+// i wonder if layouting could be automatized
+// if the graph is guaranteed to be acyclic,
+// then we could just lay them out in "columns"
 #let graph-example = canvas({
-  let x = 3
+  let x = 2.25
   let y = -3
   node((-x, -0.75 * y), ty: "const", body: "\"base.png\"", name: "base")
   node((x, -0.75 * y), ty: "const", body: "\"stencil.png\"", name: "stencil")
@@ -245,7 +248,7 @@
 
 // literally just for standalone display of the graphics alone
 #import "../../template.typ": conf
-#show: conf
+#show: conf.with(render-outline: false)
 #set page(width: auto, height: auto)
 
 #graph-example

docs/template.typ

@@ -33,22 +33,23 @@
 // this'd require wrapping the whole document in a show rule
 // at which point `query` doesn't find anything anymore
 #let terms = (
+  "processing stage",
   "source",
   "AST",
   "graph IR",
   "runtime",
-  "executor",
 
   "optimizer",
   "scheduler",
-  "VM",
+  "evaluator",
+  "evaluation",
 
   "function",
   "instruction",
-  "pipeline",
   "input", "argument", "consumer",
   "output", "streamer",
   "modifier",
+  "pipeline",
 )
 // yes, the shadowing is intentional to avoid accidentally using the list
 #let terms = regex("\\b(" + terms.map(expand).join("|") + ")\\b")
@@ -56,6 +57,7 @@
 #let conf(
   title: none,
   subtitle: none,
+  render-outline: true,
   doc,
 ) = {
   set page(
@@ -134,6 +136,7 @@
   }
 
   // outline and other prelude info
+  if render-outline {
     outline(
       indent: auto,
       fill: line(
@@ -146,6 +149,7 @@
         ),
       ),
     )
+  }
 
   // content itself
   doc

flake.nix

@@ -36,7 +36,13 @@
                     rustfmt.enable = true;
                   };
 
-                  packages = with pkgs; [just nushell typst];
+                  packages = with pkgs; [
+                    just nushell
+                    ripgrep
+                    typst typst-lsp
+                    mold
+                    cargo-nextest cargo-watch
+                  ];
                 })
               ];
             };

justfile

@@ -1,3 +1,9 @@
+all: test docs
+
+test:
+  #!/usr/bin/env nu
+  cargo nextest run
+
 # Compile all documentation as in proposals and design documents, placing them under `docs/compiled`.
 docs:
   #!/usr/bin/env nu
@@ -9,3 +15,9 @@ docs:
     )
     mv $pdf docs/compiled
   } | ignore
+
+fmt:
+  #!/usr/bin/env nu
+  cargo fmt
+  echo "Places where whitespace is at the end of a line:"
+  rg '\s$'

testfiles/bare.ron

@@ -0,0 +1,16 @@
+(
+	instructions: {
+		0: Read((
+			source: File("testfiles/rails.png"),
+		)),
+		1: Write((
+			target: File("testfiles/gen/out.jpg"),
+			format: Jpeg,
+		)),
+	},
+	edges: {
+		(on: 0, idx: 0): [
+			(on: 1, idx: 0),
+		],
+	},
+)

testfiles/bare.rpl

@@ -1,12 +0,0 @@
-(
-	[
-		Read((
-			source: File("/home/jade/example/file.png"), 
-			format: Png
-		)),
-		Write(( 
-			target: File("/home/jade/example/out.jpg"), 
-			format: Jpeg
-		))
-	]
-)

testfiles/gen/.gitkeep

@@ -0,0 +1 @@
+the testfile scripts will place generated images and media here. thank you for your understanding.

testfiles/invert.ron

@@ -0,0 +1,16 @@
+(
+	instructions: {
+		0: Read((
+			source: File("testfiles/rails.png"),
+		)),
+		1: Filter(Invert),
+		2: Write((
+			target: File("testfiles/gen/inverted.png"),
+			format: Png,
+		)),
+	},
+	edges: {
+		(on: 0, idx: 0): [(on: 1, idx: 0)],
+		(on: 1, idx: 0): [(on: 2, idx: 0)],
+	},
+)

testfiles/invert.rpl

@@ -1,13 +0,0 @@
-(
-	[
-		Read((
-			source: File("/home/jade/example/file.png"),
-			format: Png
-		)),
-		Filter(Invert),
-		Write((
-			target: File("/home/jade/example/inverted.jpg"),
-			format: Jpeg
-		))
-	]
-)