Parse function types

3 files changed, 230 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/ast/untyped/UntypedFunctionTypeNodeMatcher.java b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedFunctionTypeNodeMatcher.java
new file mode 100644
index 00000000..166dd1b0
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedFunctionTypeNodeMatcher.java
@@ -0,0 +1,48 @@
+package org.shedlang.compiler.ast.untyped;
+
+import org.pcollections.Empty;
+import org.pcollections.PVector;
+import org.shedlang.compiler.testing.MatcherBuilder;
+import org.zwobble.precisely.Matcher;
+
+import java.util.Optional;
+
+import static org.zwobble.precisely.Matchers.has;
+
+public class UntypedFunctionTypeNodeMatcher extends MatcherBuilder<
+    UntypedTypeLevelExpressionNode,
+    UntypedFunctionTypeNode,
+    UntypedFunctionTypeNodeMatcher
+> {
+    public static UntypedFunctionTypeNodeMatcher empty() {
+        return new UntypedFunctionTypeNodeMatcher(Empty.vector());
+    }
+
+    public UntypedFunctionTypeNodeMatcher(PVector<Matcher<? super UntypedFunctionTypeNode>> submatchers) {
+        super(submatchers);
+    }
+
+    @Override
+    protected Class<UntypedFunctionTypeNode> expectedType() {
+        return UntypedFunctionTypeNode.class;
+    }
+
+    @Override
+    protected UntypedFunctionTypeNodeMatcher create(
+        PVector<Matcher<? super UntypedFunctionTypeNode>> submatchers
+    ) {
+        return new UntypedFunctionTypeNodeMatcher(submatchers);
+    }
+
+    public UntypedFunctionTypeNodeMatcher withEffect(Matcher<Optional<? extends UntypedTypeLevelExpressionNode>> effect) {
+        return with(has("effect", x -> x.effect(), effect));
+    }
+
+    public UntypedFunctionTypeNodeMatcher withParams(Matcher<UntypedParamTypesNode> params) {
+        return with(has("params", x -> x.params(), params));
+    }
+
+    public UntypedFunctionTypeNodeMatcher withReturnType(Matcher<UntypedTypeLevelExpressionNode> returnType) {
+        return with(has("returnType", x -> x.returnType(), returnType));
+    }
+}
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 35e8247a..f45adba9 100644
--- a/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
@@ -123,6 +123,10 @@ public class UntypedNodeMatchers {
         );
     }
 
+    public static UntypedFunctionTypeNodeMatcher isUntypedFunctionTypeNode() {
+        return UntypedFunctionTypeNodeMatcher.empty();
+    }
+
     public static Matcher<UntypedExpressionNode> isUntypedIfNode(
         Matcher<Iterable<? extends UntypedConditionalBranchNode>> conditionalBranches,
         Matcher<UntypedBlockNode> elseBody
@@ -188,6 +192,16 @@ public class UntypedNodeMatchers {
         );
     }
 
+    public static Matcher<UntypedParamTypesNode> isUntypedParamTypesNode(
+        Matcher<Iterable<? extends UntypedTypeLevelExpressionNode>> positional,
+        Matcher<Iterable<? extends UntypedParamNode>> named
+    ) {
+        return allOf(
+            has("positional", x -> x.positional(), positional),
+            has("named", x -> x.named(), named)
+        );
+    }
+
     public static Matcher<UntypedExpressionNode> isUntypedReferenceNode(String name) {
         return instanceOf(
             UntypedReferenceNode.class,
diff --git a/src/test/java/org/shedlang/compiler/parser/ParserFunctionTypeTests.java b/src/test/java/org/shedlang/compiler/parser/ParserFunctionTypeTests.java
new file mode 100644
index 00000000..467930a3
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/parser/ParserFunctionTypeTests.java
@@ -0,0 +1,168 @@
+package org.shedlang.compiler.parser;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+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.*;
+
+public class ParserFunctionTypeTests {
+    @Test
+    public void canParseFunctionTypeWithNoParamsAndNoEffect() {
+        var source = "fn () -> Unit";
+
+        var node = parseString(source, Parser::parseTopLevelTypeLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedFunctionTypeNode()
+                .withParams(isUntypedParamTypesNode(
+                    isSequence(),
+                    isSequence()
+                ))
+                .withEffect(isOptionalEmpty())
+                .withReturnType(isUntypedTypeLevelReferenceNode("Unit"))
+        );
+    }
+
+    @Test
+    public void canParseFunctionWithSinglePositionalParam() {
+        var source = "fn (Int) -> Unit";
+
+        var node = parseString(source, Parser::parseTopLevelTypeLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedFunctionTypeNode()
+                .withParams(isUntypedParamTypesNode(
+                    isSequence(
+                        isUntypedTypeLevelReferenceNode("Int")
+                    ),
+                    isSequence()
+                ))
+        );
+    }
+
+    @Test
+    public void canParseFunctionWithManyPositionalParams() {
+        var source = "fn (Int, String, Bool) -> Unit";
+
+        var node = parseString(source, Parser::parseTopLevelTypeLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedFunctionTypeNode()
+                .withParams(isUntypedParamTypesNode(
+                    isSequence(
+                        isUntypedTypeLevelReferenceNode("Int"),
+                        isUntypedTypeLevelReferenceNode("String"),
+                        isUntypedTypeLevelReferenceNode("Bool")
+                    ),
+                    isSequence()
+                ))
+        );
+    }
+
+    @Test
+    public void canParseFunctionWithSingleNamedParam() {
+        var source = "fn (.a: Int) -> Unit";
+
+        var node = parseString(source, Parser::parseTopLevelTypeLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedFunctionTypeNode()
+                .withParams(isUntypedParamTypesNode(
+                    isSequence(),
+                    isSequence(
+                        isUntypedParamNode("a", isUntypedTypeLevelReferenceNode("Int"))
+                    )
+                ))
+        );
+    }
+
+    @Test
+    public void canParseFunctionWithManyNamedParams() {
+        var source = "fn (.a: Int, .b: String, .c: Bool) -> Unit";
+
+        var node = parseString(source, Parser::parseTopLevelTypeLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedFunctionTypeNode()
+                .withParams(isUntypedParamTypesNode(
+                    isSequence(),
+                    isSequence(
+                        isUntypedParamNode("a", isUntypedTypeLevelReferenceNode("Int")),
+                        isUntypedParamNode("b", isUntypedTypeLevelReferenceNode("String")),
+                        isUntypedParamNode("c", isUntypedTypeLevelReferenceNode("Bool"))
+                    )
+                ))
+        );
+    }
+
+    @Test
+    public void canParseNamedParamAfterPositionalParam() {
+        var source = "fn (Int, .b: String) -> Unit";
+
+        var node = parseString(source, Parser::parseTopLevelTypeLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedFunctionTypeNode()
+                .withParams(isUntypedParamTypesNode(
+                    isSequence(
+                        isUntypedTypeLevelReferenceNode("Int")
+                    ),
+                    isSequence(
+                        isUntypedParamNode("b", isUntypedTypeLevelReferenceNode("String"))
+                    )
+                ))
+        );
+    }
+
+    @Test
+    public void cannotParsePositionalParamAfterNamedParam() {
+        var source = "fn (.a: Int, String) -> Unit";
+
+        assertThrows(
+            PositionalParamAfterNamedParamError.class,
+            () -> parseString(source, Parser::parseTopLevelTypeLevelExpression)
+        );
+    }
+
+    @Test
+    public void paramsCanHaveTrailingComma() {
+        var source = """
+            fun f(a: Int, ) -> Unit {
+            }""";
+
+        var node = parseString(source, Parser::parseNamespaceStatement);
+
+        assertThat(
+            node,
+            isUntypedFunctionDefinitionNode()
+                .withParams(isUntypedParamsNode(
+                    isSequence(
+                        isUntypedParamNode("a", isUntypedTypeLevelReferenceNode("Int"))
+                    ),
+                    isSequence()
+                ))
+        );
+    }
+
+    @Test
+    public void canParseFunctionTypeWithEffect() {
+        var source = "fn () ! Io -> Unit";
+
+        var node = parseString(source, Parser::parseTopLevelTypeLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedFunctionTypeNode()
+                .withEffect(isOptionalOf(isUntypedTypeLevelReferenceNode("Io")))
+        );
+    }
+}