Parse positive ints

5 files changed, 69 insertions, 0 deletions

diff --git a/src/main/java/org/shedlang/compiler/parser/Parser.java b/src/main/java/org/shedlang/compiler/parser/Parser.java
index 7dd47250..69d02075 100644
--- a/src/main/java/org/shedlang/compiler/parser/Parser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Parser.java
@@ -6,6 +6,7 @@ import org.shedlang.compiler.tokeniser.TokenIterator;
 import org.shedlang.compiler.tokeniser.UnexpectedTokenException;
 import org.shedlang.compiler.types.NamespaceName;
 
+import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
@@ -133,6 +134,18 @@ public class Parser {
         };
     }
 
+    private static UntypedExpressionNode parseInt(TokenIterator<TokenType> tokens) {
+        var start = tokens.position();
+
+        var string = tokens.nextValue(TokenType.INT);
+        var value = new BigInteger(string);
+
+        var end = tokens.position();
+        var source = start.to(end);
+
+        return new UntypedIntLiteralNode(value, source);
+    }
+
     private static <T> List<T> parseMany(
         BooleanSupplier stop,
         Supplier<T> parseOne,
@@ -177,6 +190,8 @@ public class Parser {
         return switch (tokens.peek().tokenType()) {
 
             case IDENTIFIER -> parseReference(tokens);
+            
+            case INT -> parseInt(tokens);
 
             case STRING -> parseStringLiteral(tokens);
 
diff --git a/src/main/java/org/shedlang/compiler/parser/TokenType.java b/src/main/java/org/shedlang/compiler/parser/TokenType.java
index 734fbf8e..744bf2aa 100644
--- a/src/main/java/org/shedlang/compiler/parser/TokenType.java
+++ b/src/main/java/org/shedlang/compiler/parser/TokenType.java
@@ -3,6 +3,7 @@ package org.shedlang.compiler.parser;
 public enum TokenType {
     END,
     IDENTIFIER,
+    INT,
     STRING,
     UNKNOWN,
     WHITESPACE,
diff --git a/src/main/java/org/shedlang/compiler/parser/Tokeniser.java b/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
index 31b30ef8..6e5b3f2f 100644
--- a/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
@@ -33,6 +33,7 @@ public class Tokeniser {
             RegexTokeniser.rule(TokenType.SYMBOL_SEMICOLON, ";"),
 
             RegexTokeniser.rule(TokenType.IDENTIFIER, "[A-Za-z][A-Za-z0-9]*"),
+            RegexTokeniser.rule(TokenType.INT, "[0-9]+"),
             RegexTokeniser.rule(TokenType.STRING, "\"(?:[^\\\\\"\n\r]|\\\\.)*\""),
             RegexTokeniser.rule(TokenType.WHITESPACE, "[\r\n\t ]+")
         )
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 a848b601..acddc159 100644
--- a/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/UntypedNodeMatchers.java
@@ -2,6 +2,8 @@ package org.shedlang.compiler.ast.untyped;
 
 import org.zwobble.precisely.Matcher;
 
+import java.math.BigInteger;
+
 import static org.zwobble.precisely.Matchers.*;
 
 public class UntypedNodeMatchers {
@@ -29,6 +31,17 @@ public class UntypedNodeMatchers {
         return UntypedFunctionDefinitionNodeMatcher.empty();
     }
 
+    public static Matcher<UntypedExpressionNode> isUntypedIntLiteralNode(int value) {
+        return isUntypedIntLiteralNode(BigInteger.valueOf(value));
+    }
+
+    public static Matcher<UntypedExpressionNode> isUntypedIntLiteralNode(BigInteger value) {
+        return instanceOf(
+            UntypedIntLiteralNode.class,
+            has("value", x -> x.value(), equalTo(value))
+        );
+    }
+
     public static Matcher<UntypedNamedArgNode> isUntypedNamedArgNode(
         String name,
         Matcher<UntypedExpressionNode> expression
diff --git a/src/test/java/org/shedlang/compiler/parser/ParserIntLiteralTests.java b/src/test/java/org/shedlang/compiler/parser/ParserIntLiteralTests.java
new file mode 100644
index 00000000..61908772
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/parser/ParserIntLiteralTests.java
@@ -0,0 +1,39 @@
+package org.shedlang.compiler.parser;
+
+import org.junit.jupiter.api.Test;
+
+import static org.shedlang.compiler.ast.untyped.UntypedNodeMatchers.isUntypedIntLiteralNode;
+import static org.shedlang.compiler.parser.ParserTesting.parseString;
+import static org.zwobble.precisely.AssertThat.assertThat;
+
+public class ParserIntLiteralTests {
+    // TODO: negatives
+    // TODO: forbid leading zeroes?
+
+    @Test
+    public void canParseZero() {
+        var source = "0";
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(node, isUntypedIntLiteralNode(0));
+    }
+
+    @Test
+    public void canParseSingleDigitPositiveInt() {
+        var source = "7";
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(node, isUntypedIntLiteralNode(7));
+    }
+
+    @Test
+    public void canParseManyDigitPositiveInt() {
+        var source = "723";
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(node, isUntypedIntLiteralNode(723));
+    }
+}