Parse empty namespace

14 files changed, 173 insertions, 22 deletions

diff --git a/src/main/java/org/zwobble/hobgoblin/ast/untyped/UntypedNamespaceNode.java b/src/main/java/org/zwobble/hobgoblin/ast/untyped/UntypedNamespaceNode.java
index bbbbd8a..abcf7cc 100644
--- a/src/main/java/org/zwobble/hobgoblin/ast/untyped/UntypedNamespaceNode.java
+++ b/src/main/java/org/zwobble/hobgoblin/ast/untyped/UntypedNamespaceNode.java
@@ -1,4 +1,8 @@
 package org.zwobble.hobgoblin.ast.untyped;
 
-public class UntypedNamespaceNode {
+import org.zwobble.hobgoblin.types.NamespaceName;
+
+import java.util.List;
+
+public record UntypedNamespaceNode(NamespaceName namespaceName, List<UntypedNamespaceStatementNode> body) {
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/ast/untyped/UntypedNamespaceStatementNode.java b/src/main/java/org/zwobble/hobgoblin/ast/untyped/UntypedNamespaceStatementNode.java
new file mode 100644
index 0000000..21c20d9
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/ast/untyped/UntypedNamespaceStatementNode.java
@@ -0,0 +1,4 @@
+package org.zwobble.hobgoblin.ast.untyped;
+
+public interface UntypedNamespaceStatementNode {
+}
diff --git a/src/main/java/org/zwobble/hobgoblin/errors/SourceError.java b/src/main/java/org/zwobble/hobgoblin/errors/SourceError.java
new file mode 100644
index 0000000..1ebb679
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/errors/SourceError.java
@@ -0,0 +1,20 @@
+package org.zwobble.hobgoblin.errors;
+
+import org.zwobble.sourcetext.SourceRange;
+
+/**
+ * An error in the source code. These errors are expected when attempting to
+ * compile invalid code.
+ */
+public class SourceError extends RuntimeException {
+    private final SourceRange sourceRange;
+
+    public SourceError(String message, SourceRange sourceRange) {
+        super(message);
+        this.sourceRange = sourceRange;
+    }
+
+    public SourceRange sourceRange() {
+        return sourceRange;
+    }
+}
diff --git a/src/main/java/org/zwobble/hobgoblin/parser/ParseError.java b/src/main/java/org/zwobble/hobgoblin/parser/ParseError.java
index 27fa8c5..16b0c4f 100644
--- a/src/main/java/org/zwobble/hobgoblin/parser/ParseError.java
+++ b/src/main/java/org/zwobble/hobgoblin/parser/ParseError.java
@@ -1,8 +1,9 @@
 package org.zwobble.hobgoblin.parser;
 
+import org.zwobble.hobgoblin.errors.SourceError;
 import org.zwobble.sourcetext.SourceRange;
 
-public class ParseError extends RuntimeException {
+public class ParseError extends SourceError {
     public static ParseError unexpectedTextError(
         String expected,
         String actual,
@@ -16,14 +17,7 @@ public class ParseError extends RuntimeException {
         return new ParseError(message, sourceRange);
     }
 
-    private final SourceRange sourceRange;
-
     public ParseError(String message, SourceRange sourceRange) {
-        super(message);
-        this.sourceRange = sourceRange;
-    }
-
-    public SourceRange sourceRange() {
-        return sourceRange;
+        super(message, sourceRange);
     }
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/parser/Parser.java b/src/main/java/org/zwobble/hobgoblin/parser/Parser.java
index baa769e..ac391e8 100644
--- a/src/main/java/org/zwobble/hobgoblin/parser/Parser.java
+++ b/src/main/java/org/zwobble/hobgoblin/parser/Parser.java
@@ -1,12 +1,18 @@
 package org.zwobble.hobgoblin.parser;
 
 import org.zwobble.hobgoblin.ast.untyped.UntypedNamespaceNode;
+import org.zwobble.hobgoblin.types.NamespaceName;
+
+import java.util.List;
 
 public class Parser {
     private Parser() {
     }
 
-    public static UntypedNamespaceNode parseNamespace() {
-        return new UntypedNamespaceNode();
+    public static UntypedNamespaceNode parseNamespace(
+        TokenIterator tokens,
+        NamespaceName namespaceName
+    ) {
+        return new UntypedNamespaceNode(namespaceName, List.of());
     }
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/parser/Token.java b/src/main/java/org/zwobble/hobgoblin/parser/Token.java
index ca25fa7..a3edf50 100644
--- a/src/main/java/org/zwobble/hobgoblin/parser/Token.java
+++ b/src/main/java/org/zwobble/hobgoblin/parser/Token.java
@@ -3,4 +3,7 @@ package org.zwobble.hobgoblin.parser;
 import org.zwobble.sourcetext.SourceRange;
 
 record Token(TokenType tokenType, SourceRange sourceRange) {
+    CharSequence charSequence() {
+        return sourceRange.charSequence();
+    }
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/parser/TokenIterator.java b/src/main/java/org/zwobble/hobgoblin/parser/TokenIterator.java
index e1f4ae2..b457313 100644
--- a/src/main/java/org/zwobble/hobgoblin/parser/TokenIterator.java
+++ b/src/main/java/org/zwobble/hobgoblin/parser/TokenIterator.java
@@ -3,7 +3,25 @@ package org.zwobble.hobgoblin.parser;
 import java.util.List;
 
 class TokenIterator {
+    private final List<Token> tokens;
+    private int tokenIndex;
+    private final Token tokenEnd;
+
     TokenIterator(List<Token> tokens, Token tokenEnd) {
+        this.tokens = tokens;
+        this.tokenEnd = tokenEnd;
+        this.tokenIndex = 0;
+    }
+
+    public Token peek() {
+        return this.getAbsolute(this.tokenIndex);
+    }
 
+    private Token getAbsolute(int index) {
+        if (index < this.tokens.size()) {
+            return this.tokens.get(index);
+        } else {
+            return this.tokenEnd;
+        }
     }
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/parser/Tokenizer.java b/src/main/java/org/zwobble/hobgoblin/parser/Tokenizer.java
index a642d76..82c843d 100644
--- a/src/main/java/org/zwobble/hobgoblin/parser/Tokenizer.java
+++ b/src/main/java/org/zwobble/hobgoblin/parser/Tokenizer.java
@@ -6,14 +6,13 @@ import org.zwobble.sourcetext.SourceRange;
 import org.zwobble.sourcetext.SourceText;
 
 import java.util.ArrayList;
-import java.util.List;
 import java.util.Optional;
 
 class Tokenizer {
     private Tokenizer() {
     }
 
-    static List<Token> tokenize(SourceText sourceText) {
+    static Tokens tokenize(SourceText sourceText) {
         var iterator = new CharacterIterator(sourceText);
         var tokens = new ArrayList<Token>();
 
@@ -34,7 +33,9 @@ class Tokenizer {
             }
         }
 
-        return tokens;
+        var tokenEnd = new Token(TokenType.END, iterator.characterSourceRange());
+
+        return new Tokens(tokens, tokenEnd);
     }
 
     private static Optional<Token> tokenizeToken(CharacterIterator iterator) {
diff --git a/src/main/java/org/zwobble/hobgoblin/parser/Tokens.java b/src/main/java/org/zwobble/hobgoblin/parser/Tokens.java
new file mode 100644
index 0000000..3e979a3
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/parser/Tokens.java
@@ -0,0 +1,9 @@
+package org.zwobble.hobgoblin.parser;
+
+import java.util.List;
+
+record Tokens(List<Token> tokens, Token tokenEnd) {
+    TokenIterator iterator() {
+        return new TokenIterator(this.tokens, this.tokenEnd);
+    }
+}
diff --git a/src/main/java/org/zwobble/hobgoblin/parser/UnexpectedTokenError.java b/src/main/java/org/zwobble/hobgoblin/parser/UnexpectedTokenError.java
new file mode 100644
index 0000000..2ff6e2c
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/parser/UnexpectedTokenError.java
@@ -0,0 +1,28 @@
+package org.zwobble.hobgoblin.parser;
+
+import org.zwobble.hobgoblin.errors.SourceError;
+
+public class UnexpectedTokenError extends SourceError {
+    private final String expected;
+    private final Token actual;
+
+    public UnexpectedTokenError(
+        String expected,
+        Token actual
+    ) {
+        super(
+            "Expected: " + expected + "\nBut got: " + actual.tokenType() + " \"" + actual.charSequence() + "\"",
+            actual.sourceRange()
+        );
+        this.expected = expected;
+        this.actual = actual;
+    }
+
+    public String getExpected() {
+        return expected;
+    }
+
+    public Token getActual() {
+        return actual;
+    }
+}
diff --git a/src/main/java/org/zwobble/hobgoblin/types/NamespaceName.java b/src/main/java/org/zwobble/hobgoblin/types/NamespaceName.java
new file mode 100644
index 0000000..143d0c4
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/types/NamespaceName.java
@@ -0,0 +1,15 @@
+package org.zwobble.hobgoblin.types;
+
+import java.util.Arrays;
+import java.util.List;
+
+public record NamespaceName(List<String> parts) {
+    public static NamespaceName of(String... parts) {
+        return new NamespaceName(Arrays.asList(parts));
+    }
+
+    @Override
+    public String toString() {
+        return String.join("/", parts);
+    }
+}
diff --git a/src/test/java/org/zwobble/hobgoblin/parser/ParserNamespaceTests.java b/src/test/java/org/zwobble/hobgoblin/parser/ParserNamespaceTests.java
new file mode 100644
index 0000000..89527e9
--- /dev/null
+++ b/src/test/java/org/zwobble/hobgoblin/parser/ParserNamespaceTests.java
@@ -0,0 +1,27 @@
+package org.zwobble.hobgoblin.parser;
+
+import org.junit.jupiter.api.Test;
+import org.zwobble.hobgoblin.ast.untyped.UntypedNamespaceNode;
+import org.zwobble.hobgoblin.types.NamespaceName;
+
+import static org.zwobble.hobgoblin.parser.ParserTesting.parseString;
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.*;
+
+public class ParserNamespaceTests {
+    @Test
+    public void emptyNamespaceHasEmptyBody() {
+        var source = "";
+
+        var node = parseString(
+            source,
+            tokens -> Parser.parseNamespace(tokens, NamespaceName.of("Example", "Project"))
+        );
+
+        assertThat(node, instanceOf(
+            UntypedNamespaceNode.class,
+            has("namespaceName", x -> x.namespaceName(), equalTo(NamespaceName.of("Example", "Project"))),
+            has("body", x -> x.body(), isSequence())
+        ));
+    }
+}
diff --git a/src/test/java/org/zwobble/hobgoblin/parser/ParserTesting.java b/src/test/java/org/zwobble/hobgoblin/parser/ParserTesting.java
new file mode 100644
index 0000000..14cfb62
--- /dev/null
+++ b/src/test/java/org/zwobble/hobgoblin/parser/ParserTesting.java
@@ -0,0 +1,22 @@
+package org.zwobble.hobgoblin.parser;
+
+import org.zwobble.sourcetext.SourceText;
+
+import java.util.function.Function;
+
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.equalTo;
+
+public class ParserTesting {
+    public static <T> T parseString(
+        String sourceContents,
+        Function<TokenIterator, T> parseTokens
+    ) {
+        var sourceText = SourceText.fromString("<string>", sourceContents);
+        var tokens = Tokenizer.tokenize(sourceText);
+        var tokenIterator = tokens.iterator();
+        var result = parseTokens.apply(tokenIterator);
+        assertThat(tokenIterator.peek().tokenType(), equalTo(TokenType.END));
+        return result;
+    }
+}
diff --git a/src/test/java/org/zwobble/hobgoblin/parser/TokenizerTests.java b/src/test/java/org/zwobble/hobgoblin/parser/TokenizerTests.java
index 05848a3..6f77470 100644
--- a/src/test/java/org/zwobble/hobgoblin/parser/TokenizerTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/parser/TokenizerTests.java
@@ -15,7 +15,7 @@ public class TokenizerTests {
 
         var tokens = Tokenizer.tokenize(sourceText);
 
-        assertThat(tokens, isSequence());
+        assertThat(tokens.tokens(), isSequence());
     }
 
     @Test
@@ -24,7 +24,7 @@ public class TokenizerTests {
 
         var tokens = Tokenizer.tokenize(sourceText);
 
-        assertThat(tokens, isSequence(
+        assertThat(tokens.tokens(), isSequence(
             equalTo(new Token(TokenType.KEYWORD_STRUCT, sourceRange(sourceText, 0, 6)))
         ));
     }
@@ -35,7 +35,7 @@ public class TokenizerTests {
 
         var tokens = Tokenizer.tokenize(sourceText);
 
-        assertThat(tokens, isSequence(
+        assertThat(tokens.tokens(), isSequence(
             equalTo(new Token(TokenType.IDENTIFIER, sourceRange(sourceText, 0, 4)))
         ));
     }
@@ -46,7 +46,7 @@ public class TokenizerTests {
 
         var tokens = Tokenizer.tokenize(sourceText);
 
-        assertThat(tokens, isSequence(
+        assertThat(tokens.tokens(), isSequence(
             equalTo(new Token(TokenType.SYMBOL_BRACE_OPEN, sourceRange(sourceText, 0, 1)))
         ));
     }
@@ -57,7 +57,7 @@ public class TokenizerTests {
 
         var tokens = Tokenizer.tokenize(sourceText);
 
-        assertThat(tokens, isSequence(
+        assertThat(tokens.tokens(), isSequence(
             equalTo(new Token(TokenType.SYMBOL_BRACE_CLOSE, sourceRange(sourceText, 0, 1)))
         ));
     }
@@ -68,7 +68,7 @@ public class TokenizerTests {
 
         var tokens = Tokenizer.tokenize(sourceText);
 
-        assertThat(tokens, isSequence(
+        assertThat(tokens.tokens(), isSequence(
             equalTo(new Token(TokenType.IDENTIFIER, sourceRange(sourceText, 2, 6)))
         ));
     }
@@ -79,7 +79,7 @@ public class TokenizerTests {
 
         var tokens = Tokenizer.tokenize(sourceText);
 
-        assertThat(tokens, isSequence(
+        assertThat(tokens.tokens(), isSequence(
             equalTo(new Token(TokenType.IDENTIFIER, sourceRange(sourceText, 0, 3))),
             equalTo(new Token(TokenType.IDENTIFIER, sourceRange(sourceText, 4, 7))),
             equalTo(new Token(TokenType.IDENTIFIER, sourceRange(sourceText, 10, 15)))