.gitignore

@@ -4,3 +4,5 @@
 .pre-commit-config.yaml
 *.pdf
 /docs/*.png
+/testfiles/gen/*
+!/testfiles/gen/.gitkeep

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

@@ -1,31 +1,39 @@
-use std::mem;
-
 use ir::{
+    id,
     instruction::{Filter, Kind},
-    GraphIr, Instruction, InstructionRef,
+    GraphIr, Instruction, Map,
 };
 
-use crate::value::Dynamic;
+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) {
         // TODO: should add instead of replace, see note in Evaluator trait above this method
         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);
         }
@@ -35,23 +43,64 @@ impl crate::Evaluator for Evaluator {
 impl Evaluator {
     #[allow(clippy::needless_pass_by_value)]
     fn step(&mut self, instr: Instruction) {
-        let _ = match instr.kind {
-            Kind::Read(details) => Some(Dynamic::Image(instr::read::read(details))),
+        // 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) => {
-                instr::write::write(details, todo!());
+                #[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 => Some(Dynamic::Image(instr::filters::invert::invert(
-                    match todo!() {
-                        Some(Dynamic::Image(img)) => img,
-                        _ => panic!("invalid value type for invert"),
-                    },
-                ))),
+                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/value/mod.rs

@@ -1,5 +1,12 @@
 use image::DynamicImage;
 
-pub enum Dynamic {
+/// 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/ir/src/id.rs

@@ -49,7 +49,7 @@ impl Input {
 ///
 /// 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(super) Socket);
+pub struct Output(pub Socket); // TODO: Restrict publicness to super
 
 impl Output {
     #[must_use]
@@ -75,7 +75,7 @@ pub struct Socket {
 /// 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);
+pub struct SocketIdx(pub u16); // TODO: Restrict publicness to super
 
 impl fmt::Debug for SocketIdx {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

crates/ir/src/lib.rs

@@ -27,6 +27,8 @@ pub fn from_ron(source: &str) -> ron::error::SpannedResult<GraphIr> {
 
 /// 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).
@@ -56,6 +58,27 @@ pub fn from_ron(source: &str) -> ron::error::SpannedResult<GraphIr> {
 /// 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

crates/ir/src/value/mod.rs

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

testfiles/bare.ron

@@ -1,12 +1,12 @@
 (
 	instructions: {
 		0: Read((
-			source: File("testfiles/juan.jpg"),
-			format: Jpeg,
+			source: File("testfiles/rails.png"),
+			format: Png,
 		)),
 		1: Write((
-			target: File("testfiles/out.png"),
-			format: Png,
+			target: File("testfiles/gen/out.jpg"),
+			format: Jpeg,
 		)),
 	},
 	edges: {

testfiles/gen/.gitkeep

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

testfiles/invert.ron

@@ -1,12 +1,12 @@
 (
 	instructions: {
 		0: Read((
-			source: File("testfiles/juan.jpg"),
-			format: Jpeg,
+			source: File("testfiles/rails.png"),
+			format: Png,
 		)),
 		1: Filter(Invert),
 		2: Write((
-			target: File("testfiles/inverted.png"),
+			target: File("testfiles/gen/inverted.png"),
 			format: Png,
 		)),
 	},