From b94fc2c22021dc50381856f170fe9dca4b879468 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sat, 18 Jul 2026 19:10:38 +0100
Subject: Add iterator loop expressions to Rust AST

---
 .../compiler/output/lang/rust/RustWriter.java      | 16 ++++++++
 .../output/lang/rust/ast/RustExpression.java       |  2 +-
 .../lang/rust/ast/RustIteratorLoopExpression.java  | 48 ++++++++++++++++++++++
 3 files changed, 65 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustIteratorLoopExpression.java

(limited to 'src/main/java/org/zwobble')

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
index d4228b0..d916311 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
@@ -347,6 +347,10 @@ public class RustWriter implements AutoCloseable {
                 this.writeIntegerLiteral(integerLiteral);
             }
 
+            case RustIteratorLoopExpression iteratorLoopExpression -> {
+                this.writeIteratorLoopExpression(iteratorLoopExpression);
+            }
+
             case RustPath path -> {
                 this.writePath(path);
             }
@@ -405,6 +409,7 @@ public class RustWriter implements AutoCloseable {
             case RustFieldExpression _ -> RustPrecedence.FIELD_EXPRESSIONS;
             case RustIfExpression _ -> RustPrecedence.PRIMARY;
             case RustIntegerLiteral _ -> RustPrecedence.PRIMARY;
+            case RustIteratorLoopExpression _ -> RustPrecedence.PRIMARY;
             case RustPath _ -> RustPrecedence.PATHS;
             case RustPrefixExpression _ -> RustPrecedence.PREFIX;
             case RustStructExpression _ -> RustPrecedence.PRIMARY;
@@ -517,6 +522,17 @@ public class RustWriter implements AutoCloseable {
         }
     }
 
+    private void writeIteratorLoopExpression(
+        RustIteratorLoopExpression iteratorLoopExpression
+    ) throws IOException {
+        this.writer.write("for ");
+        this.writeIdentifier(iteratorLoopExpression.elementName());
+        this.writer.write(" in ");
+        this.writeTopLevelExpression(iteratorLoopExpression.elements());
+        this.writer.write(" ");
+        this.writeBlockExpression(iteratorLoopExpression.body());
+    }
+
     private void writePrefixExpression(RustPrefixExpression prefixExpression) throws IOException {
         this.writer.write(switch (prefixExpression.operator()) {
             case BORROW -> "&";
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustExpression.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustExpression.java
index 95ca9f8..239f972 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustExpression.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustExpression.java
@@ -5,7 +5,7 @@ package org.zwobble.hobgoblin.compiler.output.lang.rust.ast;
 // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression imports
 // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression imports
 
-public sealed interface RustExpression permits org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustArrayRepeatExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBinaryExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBoolLiteral, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustCallExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFieldExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIfExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIntegerLiteral, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustStructExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTryPropagationExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTupleExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustVecRepeatExpression {
+public sealed interface RustExpression permits org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustArrayRepeatExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBinaryExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBoolLiteral, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustCallExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFieldExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIfExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIntegerLiteral, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustStructExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTryPropagationExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTupleExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustVecRepeatExpression {
     public interface Builder {
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression build();
 
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustIteratorLoopExpression.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustIteratorLoopExpression.java
new file mode 100644
index 0000000..0cd1ceb
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustIteratorLoopExpression.java
@@ -0,0 +1,48 @@
+// Generated by hobgoblin.
+
+package org.zwobble.hobgoblin.compiler.output.lang.rust.ast;
+
+// Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression imports
+// Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression imports
+
+public record RustIteratorLoopExpression(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier elementName, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression elements, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression body) implements org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression {
+    public static org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder arbitrary() {
+        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier.arbitrary().build(), org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression.arbitrary().build(), org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression.arbitrary().build());
+    }
+
+    public record Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier elementName, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression elements, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression body) implements org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression.Builder {
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression build() {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression(elementName, elements, body);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder withElementName(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier elementName) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder(elementName, elements, body);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder withElementName(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier.Builder elementName) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder(elementName.build(), elements, body);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder withElements(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression elements) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder(elementName, elements, body);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder withElements(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression.Builder elements) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder(elementName, elements.build(), body);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder withBody(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression body) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder(elementName, elements, body);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder withBody(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression.Builder body) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder(elementName, elements, body.build());
+        }
+
+        // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder body
+        // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression.Builder body
+    }
+
+    // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression body
+    // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIteratorLoopExpression body
+}
-- 
cgit v1.2.3