Parse try expressions

7 files changed, 145 insertions, 2 deletions

diff --git a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedExpressionNode.java b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedExpressionNode.java
index e8f3842d..60f80022 100644
--- a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedExpressionNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedExpressionNode.java
@@ -1,5 +1,5 @@
 package org.shedlang.compiler.ast.untyped;
 
 public sealed interface UntypedExpressionNode extends UntypedNode
-    permits UntypedBinaryOperationNode, UntypedBoolLiteralNode, UntypedCallNode, UntypedFieldAccessNode, UntypedFunctionExpressionNode, UntypedIfNode, UntypedIntLiteralNode, UntypedReferenceNode, UntypedStringLiteralNode, UntypedTupleNode, UntypedWhenNode {
+    permits UntypedBinaryOperationNode, UntypedBoolLiteralNode, UntypedCallNode, UntypedFieldAccessNode, UntypedFunctionExpressionNode, UntypedIfNode, UntypedIntLiteralNode, UntypedReferenceNode, UntypedStringLiteralNode, UntypedTryNode, UntypedTupleNode, UntypedWhenNode {
 }
diff --git a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedTryNode.java b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedTryNode.java
new file mode 100644
index 00000000..b9146bb3
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedTryNode.java
@@ -0,0 +1,13 @@
+package org.shedlang.compiler.ast.untyped;
+
+import org.shedlang.compiler.sources.Source;
+
+import java.util.List;
+
+public record UntypedTryNode(
+    UntypedBlockNode body,
+    UntypedTypeLevelExpressionNode handledEffect,
+    List<UntypedFunctionDefinitionNode> handlers,
+    Source source
+) implements UntypedExpressionNode {
+}
diff --git a/src/main/java/org/shedlang/compiler/parser/Parser.java b/src/main/java/org/shedlang/compiler/parser/Parser.java
index 35efa5ab..1ed7799e 100644
--- a/src/main/java/org/shedlang/compiler/parser/Parser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Parser.java
@@ -363,7 +363,7 @@ public class Parser {
         }
     }
 
-    private static UntypedNamespaceStatementNode parseFunctionDefinition(TokenIterator<TokenType> tokens) {
+    private static UntypedFunctionDefinitionNode parseFunctionDefinition(TokenIterator<TokenType> tokens) {
         var start = tokens.position();
 
         var visibility = parseVisibility(tokens);
@@ -808,6 +808,8 @@ public class Parser {
 
             case KEYWORD_FN -> parseFunctionExpression(tokens);
 
+            case KEYWORD_TRY -> parseTry(tokens);
+
             case KEYWORD_WHEN -> parseWhen(tokens);
 
             case STRING -> parseStringLiteral(tokens);
@@ -1054,6 +1056,35 @@ public class Parser {
         };
     }
 
+    private static UntypedExpressionNode parseTry(
+        TokenIterator<TokenType> tokens
+    ) {
+        var start = tokens.position();
+
+        tokens.skip(TokenType.KEYWORD_TRY);
+
+        var body = parseBlock(tokens);
+
+        tokens.skip(TokenType.KEYWORD_HANDLE);
+
+        var handledEffect = parseTopLevelTypeLevelExpression(tokens);
+
+        tokens.skip(TokenType.SYMBOL_BRACE_OPEN);
+
+        var handlers = parseMany(
+            () -> tokens.isNext(TokenType.SYMBOL_BRACE_CLOSE),
+            () -> parseFunctionDefinition(tokens),
+            () -> true
+        );
+
+        tokens.skip(TokenType.SYMBOL_BRACE_CLOSE);
+
+        var end = tokens.position();
+        var source = start.to(end);
+
+        return new UntypedTryNode(body, handledEffect, handlers, source);
+    }
+
     private static UntypedExpressionNode parseTuple(
         TokenIterator<TokenType> tokens
     ) {
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index 3dcf8965..bdf185f8 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -424,6 +424,9 @@ public class TypeChecker {
             case UntypedStringLiteralNode untypedStringLiteral ->
                 typeCheckStringLiteral(untypedStringLiteral, context);
 
+            case UntypedTryNode untypedTry ->
+                throw new UnsupportedOperationException("TODO");
+
             case UntypedTupleNode untypedTuple ->
                 typeCheckTuple(untypedTuple, context);
 
diff --git a/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
index 517ca77a..a9befa70 100644
--- a/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
@@ -311,6 +311,10 @@ public class UntypedNodeMatchers {
         );
     }
 
+    public static UntypedTryNodeMatcher isUntypedTryNode() {
+        return UntypedTryNodeMatcher.empty();
+    }
+
     public static Matcher<UntypedExpressionNode> isUntypedTupleNode(
         Matcher<Iterable<? extends UntypedExpressionNode>> elements
     ) {
diff --git a/src/test/java/org/shedlang/compiler/ast/untyped/UntypedTryNodeMatcher.java b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedTryNodeMatcher.java
new file mode 100644
index 00000000..e8f3cfb6
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedTryNodeMatcher.java
@@ -0,0 +1,50 @@
+package org.shedlang.compiler.ast.untyped;
+
+import org.pcollections.PVector;
+import org.shedlang.compiler.testing.MatcherBuilder;
+import org.shedlang.compiler.util.P;
+import org.zwobble.precisely.Matcher;
+
+import static org.zwobble.precisely.Matchers.has;
+
+public class UntypedTryNodeMatcher extends MatcherBuilder<
+    UntypedExpressionNode,
+    UntypedTryNode,
+    UntypedTryNodeMatcher
+> {
+    public static UntypedTryNodeMatcher empty() {
+        return new UntypedTryNodeMatcher(P.vector());
+    }
+
+    public UntypedTryNodeMatcher(PVector<Matcher<? super UntypedTryNode>> submatchers) {
+        super(submatchers);
+    }
+
+    @Override
+    protected Class<UntypedTryNode> expectedType() {
+        return UntypedTryNode.class;
+    }
+
+    @Override
+    protected UntypedTryNodeMatcher create(
+        PVector<Matcher<? super UntypedTryNode>> submatchers
+    ) {
+        return new UntypedTryNodeMatcher(submatchers);
+    }
+
+    public UntypedTryNodeMatcher withBody(Matcher<UntypedBlockNode> body) {
+        return with(has("body", x -> x.body(), body));
+    }
+
+    public UntypedTryNodeMatcher withHandledEffect(
+        Matcher<UntypedTypeLevelExpressionNode> handledEffect
+    ) {
+        return with(has("handledEffect", x -> x.handledEffect(), handledEffect));
+    }
+
+    public UntypedTryNodeMatcher withHandlers(
+        Matcher<Iterable<? extends UntypedFunctionDefinitionNode>> handlers
+    ) {
+        return with(has("handlers", x -> x.handlers(), handlers));
+    }
+}
diff --git a/src/test/java/org/shedlang/compiler/parser/ParserTryTests.java b/src/test/java/org/shedlang/compiler/parser/ParserTryTests.java
new file mode 100644
index 00000000..951fd687
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/parser/ParserTryTests.java
@@ -0,0 +1,42 @@
+package org.shedlang.compiler.parser;
+
+import org.junit.jupiter.api.Test;
+
+import static org.shedlang.compiler.ast.untyped.UntypedNodeMatchers.*;
+import static org.shedlang.compiler.parser.ParserTesting.parseString;
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.isSequence;
+
+public class ParserTryTests {
+    @Test
+    public void canParseTry() {
+        var source = """
+            try {
+                1;
+            } handle State {
+                fun read() {
+                }
+                
+                fun write() {
+                }
+            }
+        """;
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedTryNode()
+                .withBody(isUntypedBlockNode(isSequence(
+                    isUntypedExpressionStatementNode(isUntypedIntLiteralNode(1))
+                )))
+                .withHandledEffect(isUntypedTypeLevelReferenceNode("State"))
+                .withHandlers(isSequence(
+                    isUntypedFunctionDefinitionNode()
+                        .withName("read"),
+                    isUntypedFunctionDefinitionNode()
+                        .withName("write")
+                ))
+        );
+    }
+}