Fix infinite loop bug

.github/copilot-instructions.md

@@ -40,3 +40,8 @@ the agent to update the implementation.
 
 When creating a commit, make sure that both the user's and the agent's modifications
 are included in the commit.
+
+Only create a commit when specifically asked for that. Never assume implicitly that the
+user wants you to create a commit.
+Even if they asked you to create a commit in an earlier task, it does not mean that
+you should also create a commit in a later task.

v0/ast.h

@@ -5,29 +5,82 @@
 #define AST_H
 
 #include "bool.h"
+#include "token.h"
+
 #include <stddef.h>
 
 typedef struct {
-    /* @brief The name of the module being imported. */
-    char* module_name;
+    /** @brief The name of the module being imported. */
+    const char* module_name;
 
-    /* @brief Whether the import is public or not. */
+    /** @brief Whether the import is public or not. */
     bool is_public;
 } ImportDeclaration;
 
+typedef enum {
+    TYPE_EXPRESSION_BUILTIN,
+    TYPE_EXPRESSION_ARRAY
+} TypeExpressionTag;
+
+/**
+ * An expression that evaluates to a type.
+ */
+typedef struct TypeExpression TypeExpression;
+struct TypeExpression{
+    /** @brief defines which entry in the union is valid */
+    TypeExpressionTag tag;
+    union {
+        /** @brief Evaluates to an array of the given type. */
+        struct {
+            /** @brief A pointer to the type of the elements stored in the array. */
+            TypeExpression* array;
+        } array;
+        /** @brief Evaluates to a builtin integer type.*/
+        struct {
+            /**
+             * @brief The number of bits in the integer.
+             * Typical values are 8, 16, 32, and 64.
+             */
+            int bitSize;
+            /** @brief `true` if the type is signed, `false` if it's unsigned. */
+            bool isSigned;
+        } builtin;
+    };
+};
+
+/**
+ * A declaration that aliases one type to another.
+ */
+typedef struct {
+    /** @brief The name of the alias. */
+    const char* name;
+
+    /** @brief The value of the alias. */
+    TypeExpression value;
+
+    /** @brief Whether the import is public or not. */
+    bool is_public;
+} AliasDeclaration;
+
 /**
  * The top-level model.
  * Every file matches an entire Module.
  */
 typedef struct {
-    /* @brief The name of the module. */
-    char* name;
+    /** @brief The name of the module. */
+    const char* name;
 
-    /* @brief The list of imports in the module. */
+    /** @brief The list of imports in the module. */
     ImportDeclaration* imports;
 
-    /* @brief The number of imports in the module. */
+    /** @brief The number of imports in the module. */
     size_t import_count;
+
+    /** @brief The list of aliases in the module. */
+    AliasDeclaration* aliases;
+
+    /** @brief The number of aliases in the module. */
+    size_t alias_count;
 } Module;
 
 #endif

v0/include.mk

@@ -1,4 +1,4 @@
-V0_SRC := v0/main.c v0/util.c v0/token.c v0/parser.c v0/log.c
+V0_SRC := v0/main.c v0/util.c v0/token.c v0/parser.c v0/log.c v0/str.c
 
 # V0_TEST must only include `v0/test.c` itself, as all other test C–source files are
 # included directly into `v0/test.c` using `#include "test_xyz.c"`.
@@ -11,7 +11,7 @@ V0_TEST_OBJ := $(patsubst v0/%.c,v0/bin/%.o,$(V0_TEST))
 V0_SRC_DEPS := $(V0_SRC_OBJ:.o=.d)
 V0_TEST_DEPS := $(V0_TEST_OBJ:.o=.d)
 
-CFLAGS += -Werror -Wall -pedantic -std=c89
+CFLAGS += -Werror -Wall -pedantic -std=c11
 
 v0/bin/c2: $(V0_SRC_OBJ)
 	$(CC) $(CFLAGS) -o $@ $^

v0/log.c

@@ -20,7 +20,7 @@ void log_error(const char* msg) {
     }
 }
 
-void log_on_line(Location* loc, int to_column, const char* msg, ...) {
+void log_on_line(Location* loc, const char* msg, ...) {
     /* Declarations first for C89 */
     char* line_prefix = NULL;
     char* formatted_msg = NULL;
@@ -36,7 +36,7 @@ void log_on_line(Location* loc, int to_column, const char* msg, ...) {
     line_prefix = format_string("%d| ", loc->line);
     if (!line_prefix) goto cleanup;
 
-    caret_len = to_column - loc->column_start + 1;
+    caret_len = loc->column_end - loc->column_start + 1;
     if (caret_len < 1) caret_len = 1;
 
     /* Format the message */

v0/log.h

@@ -28,10 +28,9 @@ void log_error(const char* msg);
  * It additionally supports the `%S` format specifier, which can be used to format a `String` structure from `string.h`.
  * 
  * @param loc The location where the error occurred.
- * @param to_column The column number where the error ends.
  * @param msg The error message to log. This can contain format specifiers like printf, and the additional arguments will be formatted into the message.
  * @param ... Additional arguments to format into the error message.
  */
-void log_on_line(Location* loc, int to_column, const char* msg, ...);
+void log_on_line(Location* loc, const char* msg, ...);
 
 #endif

v0/parser.c

@@ -4,110 +4,281 @@
 #include <string.h>
 #include <stdio.h>
 
-Module* parser_parse(TokenStream* ts) {
-    /* Declarations first for C89 */
-    Token t;
-    Module* module;
-    ImportDeclaration* new_imports;
-    int is_public;
+// /**
+//  * Parses an import declaration.
+//  * 
+//  * @param ts The token stream to parse from.
+//  * @param module The module being parsed.
+//  * @returns true on success, false on failure.
+//  */
+// static bool parse_import(TokenStream* ts, Module* module) {
+//     ImportDeclaration* new_imports = realloc(module->imports, (module->import_count + 1) * sizeof(ImportDeclaration));
+//     if (!new_imports) {
+//         fprintf(stderr, "Out of memory\n");
+//         exit(1);
+//     }
+//     module->imports = new_imports;
 
-    t = tokenstream_next(ts);
-	if (t.token != TOKEN_MODULE) {
-		log_on_line(&t.location, t.location.column_end, "expected 'module' keyword");
-		return NULL;
+//     Token t = tokenstream_next(ts);
+//     bool is_public = false;
+//     if (t.token == TOKEN_PUBLIC) {
+//         is_public = true;
+//         t = tokenstream_next(ts);
+//     }
+
+//     if (t.token != TOKEN_IDENTIFIER) {
+//         log_on_line(&t.location, t.location.column_end, "expected module name to import");
+//         return false;
+//     }
+    
+//     char* name = (char*)malloc(t.text.length + 1);
+//     memcpy(name, t.text.data, t.text.length);
+//     name[t.text.length] = '\0';
+
+//     module->imports[module->import_count] = (ImportDeclaration){ .module_name = name, .is_public = is_public };
+//     module->import_count++;
+
+//     t = tokenstream_next(ts);
+//     if (t.token != TOKEN_SEMICOLON) {
+//         log_on_line(&t.location, t.location.column_end, "expected ';' after import");
+//         return false;
+//     }
+//     return true;
+// }
+
+// /**
+//  * Parses an alias declaration.
+//  * 
+//  * @param ts The token stream to parse from.
+//  * @param module The module being parsed.
+//  * @returns true on success, false on failure.
+//  */
+// static bool parse_alias(TokenStream* ts, Module* module) {
+//     AliasDeclaration* new_aliases = realloc(module->aliases, (module->alias_count + 1) * sizeof(AliasDeclaration));
+//     if (!new_aliases) {
+//         fprintf(stderr, "Out of memory\n");
+//         exit(1);
+//     }
+//     module->aliases = new_aliases;
+
+//     Token t = tokenstream_next(ts);
+//     if (t.token != TOKEN_IDENTIFIER) {
+//         log_on_line(&t.location, t.location.column_end, "expected alias name");
+//         return false;
+//     }
+//     char* name = (char*)malloc(t.text.length + 1);
+//     memcpy(name, t.text.data, t.text.length);
+//     name[t.text.length] = '\0';
+//     AliasDeclaration alias;
+//     alias.name = name;
+
+//     t = tokenstream_next(ts);
+//     if (t.token != TOKEN_ASSIGN) {
+//         log_on_line(&t.location, t.location.column_end, "expected '='");
+//         return false;
+//     }
+
+//     t = tokenstream_next(ts);
+    
+//     TypeExpression type;
+//     if (t.token == TOKEN_IDENTIFIER && strncmp(t.text.data, "int32", t.text.length) == 0) {
+//         type = (TypeExpression){ .tag = TYPE_EXPRESSION_BUILTIN, .builtin = { .bitSize = 32, .isSigned = true } };
+//         t = tokenstream_next(ts);
+//         if (t.token == TOKEN_BRACKET_OPEN) {
+//             t = tokenstream_next(ts);
+//             if (t.token != TOKEN_BRACKET_CLOSE) {
+//                 log_on_line(&t.location, t.location.column_end, "expected ']'");
+//                 return false;
+//             }
+//             TypeExpression* inner = malloc(sizeof(TypeExpression));
+//             *inner = type;
+//             type = (TypeExpression){ .tag = TYPE_EXPRESSION_ARRAY, .array = { .array = inner } };
+//             t = tokenstream_next(ts);
+//         }
+//     } else {
+//         log_on_line(&t.location, t.location.column_end, "expected type");
+//         return false;
+//     }
+
+//     alias.value = type;
+    
+//     module->aliases[module->alias_count] = alias;
+//     module->alias_count++;
+
+//     if (t.token != TOKEN_SEMICOLON) {
+//         log_on_line(&t.location, t.location.column_end, "expected ';'");
+//         return false;
+//     }
+//     return true;
+// }
+
+typedef struct {
+    TokenStream* ts;
+    Token token;
+} Parser;
+
+/**
+ * Reads a new token into p->token.
+ */
+static void parser_next_token(Parser* p) {
+    p->token = tokenstream_next(p->ts);
 }
 
-    t = tokenstream_next(ts);
-    if (t.token != TOKEN_IDENTIFIER) {
-        log_on_line(&t.location, t.location.column_end, "expected module name");
-        return NULL;
+/**
+ * Reads a new token if the current token is equal to the expected token.
+ * 
+ * If they are equal, it continues to the next token.
+ * 
+ * @param p
+ * @param token The expected token.
+ * @returns `true` if the current token matches the expected, `false` if it does not.
+ */
+static bool parser_accept(Parser* p, TokenType token) {
+    if (p->token.token == token) {
+        parser_next_token(p);
+        return true;
+    }
+    return false;
 }
 
-    module = (Module*)malloc(sizeof(Module));
-    if (module == NULL) {
-        fprintf(stderr, "Out of memory\n");
-        exit(1);
+/**
+ * @copilot todo
+ */
+static bool parser_expect(Parser* p, TokenType token, const char* msg) {
+    if (parser_accept(p, token)) {
+        return true;
     }
-    module->name = NULL;
-    module->imports = NULL;
-    module->import_count = 0;
-
-	module->name = (char*)malloc(t.text.length + 1);
-	if (module->name == NULL) {
-		fprintf(stderr, "Out of memory\n");
-		exit(1);
+    log_on_line(&p->token.location, msg);
+    return false;
 }
 
-	memcpy(module->name, t.text.data, t.text.length);
-	module->name[t.text.length] = '\0';
-
-	t = tokenstream_next(ts);
-	if (t.token != TOKEN_SEMICOLON) {
-		log_on_line(&t.location, t.location.column_end, "expected ';' after module name");
-		parser_free(module);
-		return NULL;
+/**
+ * @copilot todo add docs
+ */
+static bool parser_peek(Parser* p, TokenType token) {
+    if (p->token.token == token) {
+        return true;
+    }
+    return false;
 }
 
-	module->imports = NULL;
-	module->import_count = 0;
-
-	while (1) {
-		t = tokenstream_next(ts);
-		if (t.token != TOKEN_IMPORT) {
-			break;
+/**
+ * @copilot todo add docs
+ */
+static bool parser_require(Parser* p, TokenType token, const char* msg) {
+    if (parser_peek(p, token)) {
+        return true;
+    }
+    log_on_line(&p->token.location, msg);
+    return false;
 }
 
-        new_imports = realloc(module->imports, (module->import_count + 1) * sizeof(ImportDeclaration));
-        if (!new_imports) {
-            fprintf(stderr, "Out of memory\n");
-            exit(1);
-        }
-        module->imports = new_imports;
-
-		t = tokenstream_next(ts);
-        is_public = 0;
-        if (t.token == TOKEN_IDENTIFIER && strncmp(t.text.data, "public", t.text.length) == 0) {
-            is_public = 1;
-            t = tokenstream_next(ts);
+/**
+ * Converts the current token to a string.
+ * @copilot add proper docs
+ */
+static char* parser_to_text(Parser* p) {
+    char* str = string_copy(p->token.text);
+    parser_next_token(p);
+    return str;
 }
 
-		if (t.token != TOKEN_IDENTIFIER) {
-			log_on_line(&t.location, t.location.column_end, "expected module name to import");
-			parser_free(module);
-			return NULL;
+/**
+ * Parses the "module" keyword
+ */
+static bool parse_declaration_module(Parser* p, Module* module) {
+    if (!parser_expect(p, TOKEN_MODULE, "expected keyword 'module'")) {
+        return false;
     }
 
-		module->imports[module->import_count].module_name = (char*)malloc(t.text.length + 1);
-		if (!module->imports[module->import_count].module_name) {
-			fprintf(stderr, "Out of memory\n");
-			exit(1);
+    if (!parser_require(p, TOKEN_IDENTIFIER, "expected module identifier")) {
+        return false;
     }
-		memcpy(module->imports[module->import_count].module_name, t.text.data, t.text.length);
-		module->imports[module->import_count].module_name[t.text.length] = '\0';
-		module->imports[module->import_count].is_public = is_public;
+    module->name = parser_to_text(p);
+
+    return parser_expect(p, TOKEN_SEMICOLON, "expected ';' after module name");
+}
+
+static bool parse_import(Parser* p, Module* module, bool is_public) {
     module->import_count++;
+    module->imports = realloc(module->imports, sizeof(ImportDeclaration) * module->import_count);
+    ImportDeclaration* import = &module->imports[module->import_count - 1];
 
-		t = tokenstream_next(ts);
-		if (t.token != TOKEN_SEMICOLON) {
-			log_on_line(&t.location, t.location.column_end, "expected ';' after import");
-			parser_free(module);
-			return NULL;
+    if (!parser_expect(p, TOKEN_IDENTIFIER, "expected module identifier")) {
+        return false;
     }
+
+    import->module_name = parser_to_text(p);
+    import->is_public = is_public;
+    return true;
+}
+
+static bool parse_alias(Parser* p, Module* module, bool is_public) {
+    // @copilot implement
+    return true;
+}
+
+Module* parser_parse(TokenStream* ts) {
+    Parser* p = malloc(sizeof(Parser));
+    p->ts = ts;
+    parser_next_token(p);
+
+    Module* module = malloc(sizeof(Module));
+    if (!parse_declaration_module(p, module)) {
+        goto fail;
+    }
+
+    while (!parser_peek(p, TOKEN_EOF)) {
+        bool is_public = false;
+        bool terminal = false;
+        do {
+            if (parser_accept(p, TOKEN_IMPORT)) {
+                if (!parse_import(p, module, is_public)) {
+                    goto fail;
+                }
+                terminal = true;
+            } else if (parser_accept(p, TOKEN_ALIAS)) {
+                if (!parse_alias(p, module, is_public)) {
+                    goto fail;
+                }
+                terminal = true;
+            } else if (parser_accept(p, TOKEN_PUBLIC)) {
+                is_public = true;
+            } else {
+                log_on_line(&p->token.location, "unexpected token");
+                goto fail;
+            }
+        } while (!terminal);
     }
 
     return module;
+fail:
+    free(module);
+    return NULL;
+}
+
+void free_type_expression(TypeExpression* expr) {
+    if (expr->tag == TYPE_EXPRESSION_ARRAY) {
+        free_type_expression(expr->array.array);
+        free(expr->array.array);
+    }
 }
 
 void parser_free(Module* module) {
 	if (module == NULL) return;
     if (module->imports != NULL) {
-        /* C89: declare index variable before the loop */
-        size_t i;
-        for (i = 0; i < module->import_count; i++) {
-            free(module->imports[i].module_name);
+        for(size_t i = 0; i < module->import_count; i++) {
+            free((void*)module->imports[i].module_name);
         }
         free(module->imports);
     }
-	free(module->name);
+    if (module->aliases != NULL) {
+        for(size_t i = 0; i < module->alias_count; i++) {
+            free((void*)module->aliases[i].name);
+            free_type_expression(&module->aliases[i].value);
+        }
+        free(module->aliases);
+    }
+    free((void*)module->name);
 	free(module);
 }

v0/str.c

@@ -0,0 +1,11 @@
+#include "str.h"
+
+#include <string.h>
+#include <stdlib.h>
+
+char* string_copy(String string) {
+	char* str = malloc(string.length + 1);
+	memcpy(str, string.data, string.length);
+	str[string.length] = '\0';
+	return str;
+}

v0/str.h

@@ -14,4 +14,14 @@ typedef struct {
     size_t length;
 } String;
 
+/**
+ * Creates a copy of a string.
+ * 
+ * Note that this copy has to be freed afterwards.
+ * 
+ * @param string The string to copy.
+ * @returns A null-terminated copy of the string.
+ */
+char* string_copy(String string);
+
 #endif

v0/test.c

@@ -1,9 +1,12 @@
 #include "test.h"
+
+#include "util.h"
+#include "parser.h"
+
 #include <setjmp.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-#include "util.h"
 
 static jmp_buf s_testJmp;
 static const char* s_failMsg;
@@ -11,27 +14,14 @@ static char* s_logOutput = NULL;
 static const char* s_currentTestName = NULL;
 static char* s_testSource = NULL;
 
+static Module* s_currentModule = NULL;
+static TokenStream* s_currentTokenStream = NULL;
+
 void fail(const char* msg) {
     s_failMsg = msg;
     longjmp(s_testJmp, 1);
 }
 
-void assert_not_null(void* ptr, const char* msg) {
-    if (ptr == NULL) {
-        fail(msg);
-    }
-}
-
-void assert_str(const char* expected, const char* actual, const char* msg) {
-    if (expected == NULL || actual == NULL || strcmp(expected, actual) != 0) {
-        fail(msg);
-    }
-}
-
-void assert_log(const char* expected, const char* msg) {
-    assert_str(expected, s_logOutput, msg);
-}
-
 char* read_file_content(const char* filepath) {
     FILE* f;
     long size;
@@ -53,6 +43,59 @@ char* read_file_content(const char* filepath) {
     return content;
 }
 
+void assert_not_null(void* ptr, const char* msg) {
+    if (ptr == NULL) {
+        fail(msg);
+    }
+}
+
+void assert_string(const char* expected, String actual, const char* msg) {
+    if (expected == NULL || actual.data == NULL || strlen(expected) != actual.length || strncmp(expected, actual.data, actual.length) != 0) {
+        fail(msg);
+    }
+}
+
+void assert_str(const char* expected, const char* actual, const char* msg) {
+    if (expected == NULL || actual == NULL || strcmp(expected, actual) != 0) {
+        fail(msg);
+    }
+}
+
+TokenStream* test_get_tokenstream(void) {
+    if (s_currentTokenStream == NULL) {
+        char* filepath = NULL;
+
+        filepath = format_string("v0/tests/%s.c2", s_currentTestName);
+        if (!filepath) {
+            fail("out of memory");
+            return NULL;
+        }
+        
+        if (s_testSource) free(s_testSource);
+        s_testSource = read_file_content(filepath);
+        if (!s_testSource) {
+            puts(filepath);
+            fail("could not read test source file");
+            free(filepath);
+            return NULL;
+        }
+        s_currentTokenStream = tokenstream_open(filepath, s_testSource);
+        free(filepath);
+    }
+    return s_currentTokenStream;
+}
+
+Module* test_get_ast(void) {
+    if (s_currentModule == NULL) {
+        s_currentModule = parser_parse(test_get_tokenstream());
+    }
+    return s_currentModule;
+}
+
+void assert_log(const char* expected, const char* msg) {
+    assert_str(expected, s_logOutput, msg);
+}
+
 void assert_log_file(const char* msg) {
     char* filepath = format_string("v0/tests/%s.log", s_currentTestName);
     const char* generate;
@@ -109,28 +152,6 @@ void assert_false(bool condition, const char* msg) {
     }
 }
 
-TokenStream* tokenstream_get_test(void) {
-    char* filepath = NULL;
-    TokenStream* ts = NULL;
-
-    filepath = format_string("v0/tests/%s.c2", s_currentTestName);
-    if (!filepath) {
-        fail("out of memory");
-        return NULL;
-    }
-    
-    if (s_testSource) free(s_testSource);
-    s_testSource = read_file_content(filepath);
-    if (!s_testSource) {
-        fail("could not read test source file");
-        free(filepath);
-        return NULL;
-    }
-    ts = tokenstream_open(filepath, s_testSource);
-    free(filepath);
-    return ts;
-}
-
 static void log_append(const char* msg) {
     size_t oldLen = s_logOutput ? strlen(s_logOutput) : 0;
     size_t newLen = oldLen + strlen(msg) + 1;
@@ -164,35 +185,37 @@ typedef struct {
 static int s_totalTests;
 static int s_greenTests;
 
+#define TEST(name) {#name, name},
+
 static TestCase s_tests[] = {
-    {"tokenstream_open_fail", test_tokenstream_open_fail},
-    {"tokenstream_simple_keyword", test_tokenstream_simple_keyword},
-    {"tokenstream_keywords_and_symbols", test_tokenstream_keywords_and_symbols},
-    {"tokenstream_parentheses_and_brackets", test_tokenstream_parentheses_and_brackets},
-    {"tokenstream_comma", test_tokenstream_comma},
-    {"tokenstream_whitespace_ignored", test_tokenstream_whitespace_ignored},
-    {"tokenstream_void_function_signature", test_tokenstream_void_function_signature},
-    {"tokenstream_unknown_token", test_tokenstream_unknown_token},
-    {"tokenstream_info", test_tokenstream_info},
-    {"parser_module_name", test_parser_module_name},
-    {"parser_bad_module_name", test_parser_bad_module_name},
-    {"parser_missing_semicolon_module", test_parser_missing_semicolon_module},
-    {"parser_missing_semicolon_import", test_parser_missing_semicolon_import},
-    {"parser_bad_import_name", test_parser_bad_import_name},
-    {"parser_imports", test_parser_imports},
-    {"parser_public_imports", test_parser_public_imports},
-    {"log_error", test_log_error},
-    {"log_on_line", test_log_on_line},
-    {"log_on_line_variadic", test_log_on_line_variadic},
+    TEST(test_log_error)
+    TEST(test_log_on_line_variadic)
+    TEST(test_log_on_line)
+    TEST(test_parser_alias_and_import_mix)
+    TEST(test_parser_alias_array)
+    TEST(test_parser_alias_simple)
+    TEST(test_parser_bad_import_name)
+    TEST(test_parser_bad_module_name)
+    TEST(test_parser_imports)
+    TEST(test_parser_missing_semicolon_import)
+    TEST(test_parser_missing_semicolon_module)
+    TEST(test_parser_module_name)
+    TEST(test_parser_public_imports)
+    TEST(test_tokenstream_comma)
+    TEST(test_tokenstream_info)
+    TEST(test_tokenstream_keywords_and_symbols)
+    TEST(test_tokenstream_open_fail)
+    TEST(test_tokenstream_parentheses_and_brackets)
+    TEST(test_tokenstream_simple_keyword)
+    TEST(test_tokenstream_unknown_token)
+    TEST(test_tokenstream_void_function_signature)
+    TEST(test_tokenstream_whitespace_ignored)
 };
 
 
 int main(int argc, char** argv) {
-    /* Declarations first for C89 */
     const char** failedTests;
     int failedCount;
-    int i;
-    int j;
 
     (void)argc;
     (void)argv;
@@ -200,14 +223,16 @@ int main(int argc, char** argv) {
     s_totalTests = sizeof(s_tests) / sizeof(s_tests[0]);
     s_greenTests = 0;
 
-    /* Allocate failed tests array dynamically to avoid VLAs */
+    // Allocate failed tests array dynamically to avoid VLAs
     failedTests = (const char**)malloc((s_totalTests + 1) * sizeof(const char*));
     failedCount = 0;
 
-    for (i = 0; i < s_totalTests; i++) {
-        s_currentTestName = s_tests[i].name;
+    for (int i = 0; i < s_totalTests; i++) {
+        // Add 5 to strip the 'test_' prefix.
+        s_currentTestName = s_tests[i].name + 5;
         log_set_output(log_append);
         printf("%s...", s_tests[i].name);
+        fflush(stdout);
         s_failMsg = NULL;
 
         if (setjmp(s_testJmp) == 0) {
@@ -223,6 +248,16 @@ int main(int argc, char** argv) {
             printf(" [FAIL]: %s\n", s_failMsg ? s_failMsg : "");
             failedTests[failedCount++] = s_tests[i].name;
         }
+
+        if (s_currentModule) {
+            parser_free(s_currentModule);
+            s_currentModule = NULL;
+        }
+        if (s_currentTokenStream) {
+            tokenstream_close(s_currentTokenStream);
+            s_currentTokenStream = NULL;
+        }
+        fflush(stdout);
     }
 
     if (s_testSource) free(s_testSource);
@@ -230,7 +265,7 @@ int main(int argc, char** argv) {
 
     if (failedCount > 0) {
         printf("\nFailed tests:\n");
-        for (j = 0; j < failedCount; j++) {
+        for (int j = 0; j < failedCount; j++) {
             printf("  - %s\n", failedTests[j]);
         }
     }

v0/test.h

@@ -5,6 +5,7 @@
 #define TEST_H
 
 #include "token.h"
+#include "ast.h"
 
 typedef void (*Test)(void);
 
@@ -35,6 +36,17 @@ void assert_not_null(void* ptr, const char* msg);
  */
 void assert_str(const char* expected, const char* actual, const char* msg);
 
+/**
+ * Asserts that a string has the expected value.
+ * 
+ * Calls `fail` if the assertion does not hold.
+ * 
+ * @param expected The expected value. This is typically a string literal.
+ * @param actual The actual value. This is typically an expression.
+ * @param msg The message to print if these do not match.
+ */
+void assert_string(const char* expected, String actual, const char* msg);
+
 /**
  * Asserts that the logged output matches the expected value.
  */
@@ -66,7 +78,17 @@ void assert_false(bool condition, const char* msg);
 /**
  * Get the token stream used for this test.
  * It reads from the `v0/tests/xyz.c2` file, where xyz is the test name.
+ * 
+ * At the end of the test, the tokenstream will be freed automatically by the test harness.
  */
-TokenStream* tokenstream_get_test(void);
+TokenStream* test_get_tokenstream(void);
+
+/**
+ * Gets a parsed module for the this test.
+ * It reads from the `v0/tests/xyz.c2` file, where xyz is the test name.
+ * 
+ * At the end of the test, the AST will be freed automatically by the test harness.
+ */
+Module* test_get_ast(void);
 
 #endif

v0/test_log.c

@@ -34,7 +34,7 @@ static void test_log_on_line(void) {
     loc.column_start = 12;
     loc.column_end = 13;
 
-    log_on_line(&loc, 13, "unexpected token");
+    log_on_line(&loc, "unexpected token");
     assert_log_file("expected formatted error message");
 }
 
@@ -47,6 +47,6 @@ static void test_log_on_line_variadic(void) {
     loc.column_start = 12;
     loc.column_end = 13;
 
-    log_on_line(&loc, 13, "unexpected token '%c'", 'x');
+    log_on_line(&loc, "unexpected token '%c'", 'x');
     assert_log_file("expected formatted error message with variadic args");
 }

v0/test_parser.c

@@ -1,86 +1,95 @@
 #include "test.h"
 #include "parser.h"
 #include <string.h>
+#include <stdlib.h>
 
 static void test_parser_module_name(void) {
-	TokenStream* ts = tokenstream_open("test.c", "module my_module;");
-	Module* m = parser_parse(ts);
+	Module* m = test_get_ast();
 
 	assert_not_null(m, "expected module to be parsed");
 	assert_str("my_module", m->name, "expected name 'my_module'");
-
-	parser_free(m);
-	tokenstream_close(ts);
 }
 
 static void test_parser_bad_module_name(void) {
-	TokenStream* ts = tokenstream_get_test();
-	Module* m = parser_parse(ts);
-
+	test_get_ast();
 	assert_log_file("expected error to be logged for bad module name");
-
-	parser_free(m);
-	tokenstream_close(ts);
 }
 
 static void test_parser_missing_semicolon_module(void) {
-	TokenStream* ts = tokenstream_get_test();
-	Module* m = parser_parse(ts);
-
+	test_get_ast();
 	assert_log_file("expected error for missing semicolon");
-
-	parser_free(m);
-	tokenstream_close(ts);
 }
 
 static void test_parser_missing_semicolon_import(void) {
-	TokenStream* ts = tokenstream_get_test();
-	Module* m = parser_parse(ts);
-
+	test_get_ast();
 	assert_log_file("expected error for missing semicolon");
-
-	parser_free(m);
-	tokenstream_close(ts);
 }
 
 static void test_parser_bad_import_name(void) {
-	TokenStream* ts = tokenstream_get_test();
-	Module* m = parser_parse(ts);
-
+	test_get_ast();
 	assert_log_file("expected error for bad import name");
-
-	parser_free(m);
-	tokenstream_close(ts);
 }
 
 static void test_parser_imports(void) {
-	TokenStream* ts = tokenstream_open("test.c", "module my_module; import other_module;");
-	Module* m = parser_parse(ts);
+	Module* m = test_get_ast();
 	
 	assert_not_null(m, "expected module to be parsed");
     assert_str("my_module", m->name, "expected name 'my_module'");
 	
 	assert_not_null(m->imports, "expected imports to be parsed");
-	assert_int(1, m->import_count, "expected one import");
+	assert_int(1, (int)m->import_count, "expected one import");
     assert_str("other_module", m->imports[0].module_name, "expected import name 'other_module'");
 	assert_false(m->imports[0].is_public, "expected import to not be public");
-
-	parser_free(m);
-	tokenstream_close(ts);
 }
 
 static void test_parser_public_imports(void) {
-	TokenStream* ts = tokenstream_open("test.c", "module my_module; import public other_module;");
-	Module* m = parser_parse(ts);
+	Module* m = test_get_ast();
 	
 	assert_not_null(m, "expected module to be parsed");
     assert_str("my_module", m->name, "expected name 'my_module'");
 	
 	assert_not_null(m->imports, "expected imports to be parsed");
-	assert_int(1, m->import_count, "expected one import");
+	assert_int(1, (int)m->import_count, "expected one import");
     assert_str("other_module", m->imports[0].module_name, "expected import name 'other_module'");
 	assert_true(m->imports[0].is_public, "expected import to be public");
-
-	parser_free(m);
-	tokenstream_close(ts);
+}
+
+static void test_parser_alias_simple(void) {
+	Module* m = test_get_ast();
+
+	assert_not_null(m, "expected module to be parsed");
+	assert_int(1, (int)m->alias_count, "expected correct number of aliases");
+	AliasDeclaration alias = m->aliases[0];
+	assert_str("myalias", alias.name, "expected correct alias name");
+	assert_int(TYPE_EXPRESSION_BUILTIN, alias.value.tag, "expected correct alias tag");
+	assert_int(32, alias.value.builtin.bitSize, "expected bitSize 32");
+	assert_true(alias.value.builtin.isSigned, "expected signed");
+}
+
+static void test_parser_alias_array(void) {
+	Module* m = test_get_ast();
+
+	assert_not_null(m, "expected module to be parsed");
+	assert_int(1, (int)m->alias_count, "expected correct number of aliases");
+	AliasDeclaration alias = m->aliases[0];
+	assert_str("myalias", alias.name, "expected correct alias name");
+	assert_int(TYPE_EXPRESSION_ARRAY, alias.value.tag, "expected correct alias tag");
+	TypeExpression* valueType = alias.value.array.array;
+	assert_not_null(valueType, "expected pointer to array type");
+	assert_int(TYPE_EXPRESSION_BUILTIN, valueType->tag, "expected correct type tag");
+	assert_int(32, valueType->builtin.bitSize, "expected bitSize 32");
+	assert_true(valueType->builtin.isSigned, "expected signed");
+}
+
+static void test_parser_alias_and_import_mix(void) {
+	Module* m = test_get_ast();
+    
+	assert_not_null(m, "expected module to be parsed");
+    assert_int(2, (int)m->import_count, "expected 2 imports");
+    assert_int(2, (int)m->alias_count, "expected 2 aliases");
+    
+    assert_str("foo", m->imports[0].module_name, "expected import 1 name 'foo'");
+    assert_str("bar", m->imports[1].module_name, "expected import 2 name 'bar'");
+    assert_str("myalias", m->aliases[0].name, "expected alias 1 name 'myalias'");
+    assert_str("otheralias", m->aliases[1].name, "expected alias 2 name 'otheralias'");
 }

v0/test_token.c

@@ -9,23 +9,19 @@ static void test_tokenstream_open_fail(void) {
 }
 
 static void test_tokenstream_simple_keyword(void) {
-    TokenStream* ts;
+    TokenStream* ts = test_get_tokenstream();
     Token t;
     Token eof;
 
-    ts = tokenstream_open("test.c", "module");
-
     t = tokenstream_next(ts);
     if (t.token != TOKEN_MODULE) fail("expected TOKEN_MODULE");
 
     eof = tokenstream_next(ts);
     if (eof.token != TOKEN_EOF) fail("expected EOF");
-
-    tokenstream_close(ts);
 }
 
 static void test_tokenstream_keywords_and_symbols(void) {
-	TokenStream* ts = tokenstream_open("test.c", "module main; import stdio;");
+	TokenStream* ts = test_get_tokenstream();
 
 	if (tokenstream_next(ts).token != TOKEN_MODULE) fail("expected TOKEN_MODULE");
 	if (tokenstream_next(ts).token != TOKEN_IDENTIFIER) fail("expected TOKEN_IDENTIFIER (main)");
@@ -34,24 +30,20 @@ static void test_tokenstream_keywords_and_symbols(void) {
 	if (tokenstream_next(ts).token != TOKEN_IDENTIFIER) fail("expected TOKEN_IDENTIFIER (stdio)");
 	if (tokenstream_next(ts).token != TOKEN_SEMICOLON) fail("expected TOKEN_SEMICOLON");
 	if (tokenstream_next(ts).token != TOKEN_EOF) fail("expected EOF");
-
-	tokenstream_close(ts);
 }
 
 static void test_tokenstream_parentheses_and_brackets(void) {
-	TokenStream* ts = tokenstream_open("test.c", "()[]");
+	TokenStream* ts = test_get_tokenstream();
 
 	if (tokenstream_next(ts).token != TOKEN_PARENT_OPEN) fail("expected TOKEN_PARENT_OPEN");
 	if (tokenstream_next(ts).token != TOKEN_PARENT_CLOSE) fail("expected TOKEN_PARENT_CLOSE");
 	if (tokenstream_next(ts).token != TOKEN_BRACKET_OPEN) fail("expected TOKEN_BRACKET_OPEN");
 	if (tokenstream_next(ts).token != TOKEN_BRACKET_CLOSE) fail("expected TOKEN_BRACKET_CLOSE");
 	if (tokenstream_next(ts).token != TOKEN_EOF) fail("expected EOF");
-
-	tokenstream_close(ts);
 }
 
 static void test_tokenstream_comma(void) {
-	TokenStream* ts = tokenstream_open("test.c", "a,b,c");
+	TokenStream* ts = test_get_tokenstream();
 
 	if (tokenstream_next(ts).token != TOKEN_IDENTIFIER) fail("expected a");
 	if (tokenstream_next(ts).token != TOKEN_COMMA) fail("expected comma");
@@ -59,75 +51,49 @@ static void test_tokenstream_comma(void) {
 	if (tokenstream_next(ts).token != TOKEN_COMMA) fail("expected comma");
 	if (tokenstream_next(ts).token != TOKEN_IDENTIFIER) fail("expected c");
 	if (tokenstream_next(ts).token != TOKEN_EOF) fail("expected EOF");
-
-	tokenstream_close(ts);
 }
 
 static void test_tokenstream_whitespace_ignored(void) {
-	TokenStream* ts = tokenstream_open("test.c", "  module  \n\t import  ;  ");
+	TokenStream* ts = test_get_tokenstream();
 
 	if (tokenstream_next(ts).token != TOKEN_MODULE) fail("expected TOKEN_MODULE");
 	if (tokenstream_next(ts).token != TOKEN_IMPORT) fail("expected TOKEN_IMPORT");
 	if (tokenstream_next(ts).token != TOKEN_SEMICOLON) fail("expected TOKEN_SEMICOLON");
 	if (tokenstream_next(ts).token != TOKEN_EOF) fail("expected EOF");
-
-	tokenstream_close(ts);
 }
 
 static void test_tokenstream_void_function_signature(void) {
-	TokenStream* ts = tokenstream_open("test.c", "void main()");
+	TokenStream* ts = test_get_tokenstream();
 
 	if (tokenstream_next(ts).token != TOKEN_VOID) fail("expected TOKEN_VOID");
 	if (tokenstream_next(ts).token != TOKEN_IDENTIFIER) fail("expected TOKEN_IDENTIFIER");
 	if (tokenstream_next(ts).token != TOKEN_PARENT_OPEN) fail("expected TOKEN_PARENT_OPEN");
 	if (tokenstream_next(ts).token != TOKEN_PARENT_CLOSE) fail("expected TOKEN_PARENT_CLOSE");
 	if (tokenstream_next(ts).token != TOKEN_EOF) fail("expected EOF");
-
-	tokenstream_close(ts);
 }
 
 static void test_tokenstream_unknown_token(void) {
-	TokenStream* ts = tokenstream_get_test();
+	TokenStream* ts = test_get_tokenstream();
 
 	if (tokenstream_next(ts).token != TOKEN_UNKNOWN) fail("expected TOKEN_UNKNOWN");
 
 	assert_log_file("expected error message for unknown token");
-
-	tokenstream_close(ts);
 }
 
 static void test_tokenstream_info(void) {
-    TokenStream* ts;
+    TokenStream* ts = test_get_tokenstream();
     Token t1;
     Token t2;
-    char* buf1;
-    char* buf2;
-
-    ts = tokenstream_open("test.c", "module main;");
 
     t1 = tokenstream_next(ts);
     if (t1.token != TOKEN_MODULE) fail("expected TOKEN_MODULE");
-    
-    buf1 = malloc((size_t)t1.text.length + 1);
-    if (!buf1) fail("out of memory");
-    memcpy(buf1, t1.text.data, t1.text.length);
-    buf1[t1.text.length] = '\0';
-    assert_str("module", buf1, "info: expected 'module'");
+    assert_string("module", t1.text, "info: expected 'module'");
     if (t1.location.line != 1) fail("expected line 1");
     if (t1.location.column_start != 1) fail("expected column 1");
 
     t2 = tokenstream_next(ts);
     if (t2.token != TOKEN_IDENTIFIER) fail("expected TOKEN_IDENTIFIER");
-    
-    buf2 = malloc((size_t)t2.text.length + 1);
-    if (!buf2) { free(buf1); fail("out of memory"); }
-    memcpy(buf2, t2.text.data, t2.text.length);
-    buf2[t2.text.length] = '\0';
-    assert_str("main", buf2, "info: expected 'main'");
+    assert_string("main", t2.text, "info: expected 'main'");
     if (t2.location.line != 1) fail("expected line 1");
     if (t2.location.column_start != 8) fail("expected column 8");
-
-    free(buf1);
-    free(buf2);
-    tokenstream_close(ts);
 }

v0/tests/parser_alias_and_import_mix.c2

@@ -0,0 +1,9 @@
+module mymodule;
+
+import foo;
+
+alias myalias = int32[];
+
+import bar;
+
+alias otheralias = int32;

v0/tests/parser_alias_array.c2

@@ -0,0 +1,3 @@
+module mymodule;
+
+alias myalias = int32[];

v0/tests/parser_alias_simple.c2

@@ -0,0 +1,3 @@
+module mymodule;
+
+alias myalias = int32;

v0/tests/parser_imports.c2

@@ -0,0 +1,2 @@
+module my_module;
+import other_module;

v0/tests/parser_module_name.c2

@@ -0,0 +1 @@
+module my_module;

v0/tests/parser_public_imports.c2

@@ -0,0 +1,3 @@
+module my_module;
+
+public import other_module;

v0/tests/tokenstream_comma.c2

@@ -0,0 +1 @@
+a,b,c

v0/tests/tokenstream_info.c2

@@ -0,0 +1 @@
+module main;

v0/tests/tokenstream_keywords_and_symbols.c2

@@ -0,0 +1 @@
+module main; import stdio;

v0/tests/tokenstream_parentheses_and_brackets.c2

@@ -0,0 +1 @@
+()[]

v0/tests/tokenstream_simple_keyword.c2

@@ -0,0 +1 @@
+module

v0/tests/tokenstream_void_function_signature.c2

@@ -0,0 +1 @@
+void main()

v0/tests/tokenstream_whitespace_ignored.c2

@@ -0,0 +1,2 @@
+  module  
+	 import  ;  

v0/token.c

@@ -26,10 +26,11 @@ typedef struct {
 	const char* keyword;
 	TokenType token;
 } KeywordMap;
-
 static const KeywordMap keywords[] = {
 	{"module", TOKEN_MODULE},
 	{"import", TOKEN_IMPORT},
+    {"alias", TOKEN_ALIAS},
+    {"public", TOKEN_PUBLIC},
 	{"void", TOKEN_VOID},
 };
 
@@ -220,6 +221,7 @@ Token tokenstream_next(TokenStream* ts) {
 	case ']': return create_token(ts, TOKEN_BRACKET_CLOSE, start_text, 1, start_line, start_column, line_start);
 	case ',': return create_token(ts, TOKEN_COMMA, start_text, 1, start_line, start_column, line_start);
 	case ';': return create_token(ts, TOKEN_SEMICOLON, start_text, 1, start_line, start_column, line_start);
+    case '=': return create_token(ts, TOKEN_ASSIGN, start_text, 1, start_line, start_column, line_start);
 	}
 
 	/* Keywords and identifiers */
@@ -239,6 +241,6 @@ Token tokenstream_next(TokenStream* ts) {
 
 	/* Unknown character */
     t = create_token(ts, TOKEN_UNKNOWN, start_text, 1, start_line, start_column, line_start);
-	log_on_line(&t.location, t.location.column_end, "unexpected token '%c'", c);
+	log_on_line(&t.location, "unexpected token '%c'", c);
 	return t;
 }

v0/token.h

@@ -14,6 +14,8 @@ typedef enum {
     TOKEN_MODULE,
 	TOKEN_IMPORT,
 	TOKEN_SEMICOLON,
+    TOKEN_ALIAS,
+    TOKEN_PUBLIC,
 
     /* Symbols */
     TOKEN_PARENT_OPEN,
@@ -21,9 +23,11 @@ typedef enum {
 	TOKEN_BRACKET_OPEN,
 	TOKEN_BRACKET_CLOSE,
 	TOKEN_COMMA,
+    TOKEN_ASSIGN,
 
     /* Primitives */
     TOKEN_VOID,
+    TOKEN_BUILTIN_TYPE,
 
     /* Variable */
     TOKEN_IDENTIFIER,

v0/types.h

@@ -0,0 +1,9 @@
+/**
+ * Contains runtime information about types.
+ */
+#ifndef TYPES_H
+#define TYPES_H
+
+
+
+#endif