From 7669641f3ea508a010ac79d951033be22bbce51b Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sat, 19 Aug 2023 10:39:33 +0100
Subject: Parse bool literals

---
 .../java/org/shedlang/compiler/parser/Parser.java  | 16 +++++++++++++
 .../org/shedlang/compiler/parser/TokenType.java    |  2 ++
 .../org/shedlang/compiler/parser/Tokeniser.java    |  2 ++
 .../compiler/ast/untyped/UntypedNodeMatchers.java  |  7 ++++++
 .../compiler/parser/ParserBoolLiteralTests.java    | 27 ++++++++++++++++++++++
 5 files changed, 54 insertions(+)
 create mode 100644 src/test/java/org/shedlang/compiler/parser/ParserBoolLiteralTests.java

(limited to 'src')

diff --git a/src/main/java/org/shedlang/compiler/parser/Parser.java b/src/main/java/org/shedlang/compiler/parser/Parser.java
index 8ffed6c5..9bf95612 100644
--- a/src/main/java/org/shedlang/compiler/parser/Parser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Parser.java
@@ -156,6 +156,20 @@ public class Parser {
         }
     }
 
+    private static UntypedExpressionNode parseBoolLiteral(TokenIterator<TokenType> tokens) {
+        var start = tokens.position();
+
+        var value = tokens.trySkip(TokenType.KEYWORD_TRUE);
+        if (!value) {
+            tokens.skip(TokenType.KEYWORD_FALSE);
+        }
+
+        var end = tokens.position();
+        var source = start.to(end);
+
+        return new UntypedBoolLiteralNode(value, source);
+    }
+
     private static class CallParser implements OperationParser {
         @Override
         public OperatorPrecedence precedence() {
@@ -442,6 +456,8 @@ public class Parser {
             
             case KEYWORD_IF -> parseIf(tokens);
 
+            case KEYWORD_FALSE, KEYWORD_TRUE -> parseBoolLiteral(tokens);
+
             case STRING -> parseStringLiteral(tokens);
 
             default ->
diff --git a/src/main/java/org/shedlang/compiler/parser/TokenType.java b/src/main/java/org/shedlang/compiler/parser/TokenType.java
index bd4f71bd..e9855d4b 100644
--- a/src/main/java/org/shedlang/compiler/parser/TokenType.java
+++ b/src/main/java/org/shedlang/compiler/parser/TokenType.java
@@ -10,9 +10,11 @@ public enum TokenType {
 
     KEYWORD_ASSIGN,
     KEYWORD_ELSE,
+    KEYWORD_FALSE,
     KEYWORD_FUN,
     KEYWORD_IF,
     KEYWORD_RETURN,
+    KEYWORD_TRUE,
     KEYWORD_VAL,
     KEYWORD_VAR,
     KEYWORD_WHILE,
diff --git a/src/main/java/org/shedlang/compiler/parser/Tokeniser.java b/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
index 80b97c35..68df3876 100644
--- a/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
@@ -15,9 +15,11 @@ public class Tokeniser {
     private static final Map<String, TokenType> KEYWORDS = Map.ofEntries(
         Map.entry("assign", TokenType.KEYWORD_ASSIGN),
         Map.entry("else", TokenType.KEYWORD_ELSE),
+        Map.entry("false", TokenType.KEYWORD_FALSE),
         Map.entry("fun", TokenType.KEYWORD_FUN),
         Map.entry("if", TokenType.KEYWORD_IF),
         Map.entry("return", TokenType.KEYWORD_RETURN),
+        Map.entry("true", TokenType.KEYWORD_TRUE),
         Map.entry("val", TokenType.KEYWORD_VAL),
         Map.entry("var", TokenType.KEYWORD_VAR),
         Map.entry("while", TokenType.KEYWORD_WHILE)
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 564d7609..a05c8e55 100644
--- a/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
@@ -60,6 +60,13 @@ public class UntypedNodeMatchers {
         );
     }
 
+    public static Matcher<UntypedExpressionNode> isUntypedBoolLiteralNode(boolean value) {
+        return instanceOf(
+            UntypedBoolLiteralNode.class,
+            has("value", x -> x.value(), equalTo(value))
+        );
+    }
+
     public static UntypedCallNodeMatcher isUntypedCallNode() {
         return UntypedCallNodeMatcher.empty();
     }
diff --git a/src/test/java/org/shedlang/compiler/parser/ParserBoolLiteralTests.java b/src/test/java/org/shedlang/compiler/parser/ParserBoolLiteralTests.java
new file mode 100644
index 00000000..e056b8ad
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/parser/ParserBoolLiteralTests.java
@@ -0,0 +1,27 @@
+package org.shedlang.compiler.parser;
+
+import org.junit.jupiter.api.Test;
+
+import static org.shedlang.compiler.ast.untyped.UntypedNodeMatchers.isUntypedBoolLiteralNode;
+import static org.shedlang.compiler.parser.ParserTesting.parseString;
+import static org.zwobble.precisely.AssertThat.assertThat;
+
+public class ParserBoolLiteralTests {
+    @Test
+    public void canParseFalse() {
+        var source = "false";
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(node, isUntypedBoolLiteralNode(false));
+    }
+
+    @Test
+    public void canParseTrue() {
+        var source = "true";
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(node, isUntypedBoolLiteralNode(true));
+    }
+}
-- 
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