From 46ac40c94a250e38d217fac1e75af102f898c4b5 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Wed, 19 Jul 2023 20:43:49 +0100
Subject: Add return to Patio IR

---
 .../org/shedlang/compiler/patio/PatioInstructionSerializer.java  | 5 ++++-
 .../org/shedlang/compiler/patio/instructions/PatioDiscard.java   | 3 +++
 .../shedlang/compiler/patio/instructions/PatioInstruction.java   | 2 +-
 .../org/shedlang/compiler/patio/instructions/PatioReturn.java    | 9 +++++++++
 4 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 src/main/java/org/shedlang/compiler/patio/instructions/PatioReturn.java

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java b/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
index 44ec7a19..523eabc7 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
@@ -2,6 +2,7 @@ package org.shedlang.compiler.patio;
 
 import org.shedlang.compiler.patio.instructions.PatioDiscard;
 import org.shedlang.compiler.patio.instructions.PatioInstruction;
+import org.shedlang.compiler.patio.instructions.PatioReturn;
 import org.shedlang.compiler.treetext.Tree;
 
 import java.util.List;
@@ -32,9 +33,11 @@ public class PatioInstructionSerializer {
 
     private static Tree instructionToTree(PatioInstruction instruction) {
         return switch (instruction) {
-
             case PatioDiscard discard ->
                 treeList(treeIdentifier("discard"));
+
+            case PatioReturn patioReturn ->
+                treeList(treeIdentifier("return"));
         };
     }
 }
diff --git a/src/main/java/org/shedlang/compiler/patio/instructions/PatioDiscard.java b/src/main/java/org/shedlang/compiler/patio/instructions/PatioDiscard.java
index 859e6b6b..18cff4c3 100644
--- a/src/main/java/org/shedlang/compiler/patio/instructions/PatioDiscard.java
+++ b/src/main/java/org/shedlang/compiler/patio/instructions/PatioDiscard.java
@@ -2,5 +2,8 @@ package org.shedlang.compiler.patio.instructions;
 
 import org.shedlang.compiler.sources.Source;
 
+/**
+ * Pop a value from the stack and discard it.
+ */
 public record PatioDiscard(Source source) implements PatioInstruction {
 }
diff --git a/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java b/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
index bc4de280..22305e84 100644
--- a/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
+++ b/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
@@ -2,6 +2,6 @@ package org.shedlang.compiler.patio.instructions;
 
 import org.shedlang.compiler.sources.Source;
 
-public sealed interface PatioInstruction permits PatioDiscard {
+public sealed interface PatioInstruction permits PatioDiscard, PatioReturn {
     Source source();
 }
diff --git a/src/main/java/org/shedlang/compiler/patio/instructions/PatioReturn.java b/src/main/java/org/shedlang/compiler/patio/instructions/PatioReturn.java
new file mode 100644
index 00000000..cf7e7990
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/patio/instructions/PatioReturn.java
@@ -0,0 +1,9 @@
+package org.shedlang.compiler.patio.instructions;
+
+import org.shedlang.compiler.sources.Source;
+
+/**
+ * Pop a value from the stack and return with that value from the current function.
+ */
+public record PatioReturn(Source source) implements PatioInstruction {
+}
-- 
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