Add borrow expressions to Rust AST

7 files changed, 130 insertions, 1 deletions

diff --git a/hobgoblin/src/output/lang/rust/ast.hob b/hobgoblin/src/output/lang/rust/ast.hob
index 56cbb1a..884f4d4 100644
--- a/hobgoblin/src/output/lang/rust/ast.hob
+++ b/hobgoblin/src/output/lang/rust/ast.hob
@@ -125,6 +125,7 @@ sum RustExpression {
     variant RustCallExpression;
     variant RustFieldExpression;
     variant RustPath;
+    variant RustPrefixExpression;
     variant RustStructExpression;
 }
 
@@ -147,6 +148,15 @@ struct RustFieldExpression {
     field fieldName: RustIdentifier;
 }
 
+struct RustPrefixExpression {
+    field operator: RustPrefixOperator;
+    field operand: RustExpression;
+}
+
+enum RustPrefixOperator {
+    variant borrow;
+}
+
 struct RustStructExpression {
     field structPath: RustPath;
     field fieldValues: List[RustStructExprField];
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 60641c8..c0550fd 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
@@ -324,6 +324,10 @@ public class RustWriter implements AutoCloseable {
             case RustPath path -> {
                 this.writePath(path);
             }
+            
+            case RustPrefixExpression prefixExpression -> {
+                this.writePrefixExpression(prefixExpression);
+            }
 
             case RustStructExpression structExpression -> {
                 this.writeStructExpression(structExpression);
@@ -373,6 +377,13 @@ public class RustWriter implements AutoCloseable {
         this.writeIdentifier(fieldExpression.fieldName());
     }
 
+    private void writePrefixExpression(RustPrefixExpression prefixExpression) throws IOException {
+        this.writer.write(switch (prefixExpression.operator()) {
+            case BORROW -> "&";
+        });
+        this.writeExpression(prefixExpression.operand());
+    }
+
     private void writeStructExpression(RustStructExpression structExpression) throws IOException {
         this.writePath(structExpression.structPath());
         this.writer.write(" {");
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 3a14bec..9d6fdcb 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.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.RustPath, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustStructExpression {
+public sealed interface RustExpression permits 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.RustPath, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustStructExpression {
     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/RustPrefixExpression.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixExpression.java
new file mode 100644
index 0000000..540312f
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixExpression.java
@@ -0,0 +1,36 @@
+// Generated by hobgoblin.
+
+package org.zwobble.hobgoblin.compiler.output.lang.rust.ast;
+
+// Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression imports
+// Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression imports
+
+public record RustPrefixExpression(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator operator, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression operand) implements org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression {
+    public static org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder arbitrary() {
+        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator.BORROW, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustBlockExpression.arbitrary().build());
+    }
+
+    public record Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator operator, org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression operand) implements org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression.Builder {
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression build() {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression(operator, operand);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder withOperator(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator operator) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder(operator, operand);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder withOperand(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression operand) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder(operator, operand);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder withOperand(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression.Builder operand) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder(operator, operand.build());
+        }
+
+        // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder body
+        // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.Builder body
+    }
+
+    // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression body
+    // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression body
+}
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixOperator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixOperator.java
new file mode 100644
index 0000000..d5c69c1
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixOperator.java
@@ -0,0 +1,13 @@
+// Generated by hobgoblin.
+
+package org.zwobble.hobgoblin.compiler.output.lang.rust.ast;
+
+// Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator imports
+// Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator imports
+
+public enum RustPrefixOperator {
+    BORROW
+
+    // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator body
+    // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator body
+}
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
index 625526b..7f85b8a 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
@@ -497,6 +497,20 @@ public class RustWriterTests {
         assertThat(string, equalTo("x.y"));
     }
 
+    // === Prefix expressions ===
+
+    @Test
+    public void borrowExpression() throws IOException {
+        var rust = RustPrefixExpression.arbitrary()
+            .withOperator(RustPrefixOperator.BORROW)
+            .withOperand(RustPath.of("x"))
+            .build();
+
+        var string = write(writer -> writer.writeExpression(rust));
+
+        assertThat(string, equalTo("&x"));
+    }
+
     // === Struct expressions ===
 
     @Test
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixExpressionMatcher.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixExpressionMatcher.java
new file mode 100644
index 0000000..dc3d418
--- /dev/null
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustPrefixExpressionMatcher.java
@@ -0,0 +1,45 @@
+// Generated by hobgoblin.
+
+package org.zwobble.hobgoblin.compiler.output.lang.rust.ast;
+
+// Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher imports
+// Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher imports
+
+public class RustPrefixExpressionMatcher implements org.zwobble.precisely.Matcher<java.lang.Object> {
+    public static org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher isRustPrefixExpression() {
+        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher(java.util.List.of());
+    }
+
+    private final java.util.List<org.zwobble.precisely.Matcher<? super org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression>> submatchers;
+
+    private RustPrefixExpressionMatcher(java.util.List<org.zwobble.precisely.Matcher<? super org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression>> submatchers) {
+        this.submatchers = submatchers;
+    }
+
+    public org.zwobble.precisely.MatchResult match(java.lang.Object actual) {
+        return this.toMatcher().match(actual);
+    }
+
+    public org.zwobble.precisely.TextTree describe() {
+        return this.toMatcher().describe();
+    }
+
+    private org.zwobble.precisely.Matcher<java.lang.Object> toMatcher() {
+        return org.zwobble.precisely.Matchers.instanceOf(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression.class, this.submatchers);
+    }
+
+    public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher withOperator(org.zwobble.precisely.Matcher<? super org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixOperator> operator) {
+        var submatchers = new java.util.ArrayList<org.zwobble.precisely.Matcher<? super org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression>>(this.submatchers);
+        submatchers.add(org.zwobble.precisely.Matchers.has("operator", org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression::operator, operator));
+        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher(submatchers);
+    }
+
+    public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher withOperand(org.zwobble.precisely.Matcher<? super org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustExpression> operand) {
+        var submatchers = new java.util.ArrayList<org.zwobble.precisely.Matcher<? super org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression>>(this.submatchers);
+        submatchers.add(org.zwobble.precisely.Matchers.has("operand", org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpression::operand, operand));
+        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher(submatchers);
+    }
+
+    // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher body
+    // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPrefixExpressionMatcher body
+}