parser: Add support for variables and identifiers in function body

This commit adds support for variables and identifiers in the function
body of the parser, stored as a vector.

However, at this point, identifier resolution is not fully implemented,
and we currently accept identifiers without checking if they can be
resolved. This is a known limitation that will be addressed in a future
commit once hash-tables are added to the parser.

Signed-off-by: Carlos Maniero <carlosmaniero@gmail.com>
Reviewed-by: Johnny Richard <johnny@johnnyrichard.com>

3 files changed, 54 insertions, 5 deletions

diff --git a/test/Makefile b/test/Makefile
index 09adcfb..40f5cf9 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -23,7 +23,7 @@ vector_test: munit.o ../build/vector.o vector_test.o
 lexer_test: munit.o ../build/string_view.o ../build/lexer.o lexer_test.o
 	$(CC) $? $(CFLAGS) -o $@
 
-parser_test: munit.o ../build/string_view.o ../build/lexer.o ../build/ast.o ../build/parser.o parser_test.o
+parser_test: munit.o ../build/string_view.o ../build/vector.o ../build/lexer.o ../build/ast.o ../build/parser.o parser_test.o
 	$(CC) $? $(CFLAGS) -o $@
 
 integration_test: munit.o integration_test.o
diff --git a/test/lexer_test.c b/test/lexer_test.c
index ae713b3..0eebfe5 100644
--- a/test/lexer_test.c
+++ b/test/lexer_test.c
@@ -71,6 +71,7 @@ test_tokenize_op(const  MunitParameter params[],
   assert_token_at("  - \n", 0, TOKEN_OP, "-");
   assert_token_at("  * ;",  0, TOKEN_OP, "*");
   assert_token_at("  / ",   0, TOKEN_OP, "/");
+  assert_token_at("  = ",   0, TOKEN_OP, "=");
 
   assert_token_at("1 * 2", 0, TOKEN_NUMBER, "1");
   assert_token_at("1 * 2", 1, TOKEN_OP, "*");
diff --git a/test/parser_test.c b/test/parser_test.c
index 2e73fa6..daa2fe7 100644
--- a/test/parser_test.c
+++ b/test/parser_test.c
@@ -15,11 +15,12 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 #define MUNIT_ENABLE_ASSERT_ALIASES
-#include "munit.h"
+#include "ast.h"
 #include "lexer.h"
+#include "munit.h"
 #include "parser.h"
-#include "ast.h"
 #include "string.h"
+#include "vector.h"
 
 void assert_string_view_equal(char *expected, string_view_t actual);
 
@@ -49,6 +50,8 @@ assert_parser_error(char* src, char* error_msg) {
   assert_false(parsed);
   assert_int(1, ==, parser.errors_len);
   assert_string_equal(error_msg, parser.errors[0].message);
+
+  ast_node_destroy(ast_function);
 }
 
 static MunitResult
@@ -71,7 +74,7 @@ test_parse_function(const MunitParameter params[],
   assert_string_equal("main", actual);
   assert_int(AST_FUNCTION_DECLARATION, ==, ast_function->kind);
 
-  ast_node_t *ast_return = ast_function->data.function.body;
+  ast_node_t *ast_return = vector_at(ast_function->data.function.body, 0);
 
   assert_int(AST_RETURN_STMT, ==, ast_return->kind);
 
@@ -86,6 +89,46 @@ test_parse_function(const MunitParameter params[],
 }
 
 static MunitResult
+test_parse_variable_definition(const MunitParameter params[],
+                               void *user_data_or_fixture)
+{
+  parser_t parser;
+  lexer_t lexer;
+
+  make_lexer_from_static_src(&lexer, "main(): i32 { \nvariable : i32 = 42; \nreturn variable;\n }");
+  parser_init(&parser, &lexer);
+  ast_node_t *ast_function = ast_node_new();
+
+  bool parsed = parser_parse_function_declaration(&parser, ast_function);
+
+  assert_true(parsed);
+
+  char actual[5];
+
+  string_view_to_str(&ast_function->data.function.name, actual);
+  assert_string_equal("main", actual);
+  assert_int(AST_FUNCTION_DECLARATION, ==, ast_function->kind);
+
+  ast_node_t *ast_variable = vector_at(ast_function->data.function.body, 0);
+
+  assert_int(AST_VARIABLE_DECLARATION, ==, ast_variable->kind);
+  assert_string_view_equal("variable", ast_variable->data.variable.name);
+
+  ast_node_t *ast_return = vector_at(ast_function->data.function.body, 1);
+
+  assert_int(AST_RETURN_STMT, ==, ast_return->kind);
+
+  ast_node_t *ast_literal = ast_return->data.return_stmt.argument;
+
+  assert_int(AST_IDENTIFIER, ==, ast_literal->kind);
+  assert_string_view_equal("variable", ast_literal->data.identifier.name);
+
+  ast_node_destroy(ast_function);
+
+  return MUNIT_OK;
+}
+
+static MunitResult
 test_parse_arithmetic_expression(const MunitParameter params[],
                                  void *user_data_or_fixture)
 {
@@ -167,15 +210,20 @@ test_parse_basic_syntax_errors(const MunitParameter params[],
   assert_parser_error("main(): i32 { return; }"     , "unexpected '; (;)' token");
   assert_parser_error("main(): i32 { return 42;"    , "expected '}' but got end of file");
   assert_parser_error("main(): beff { return 42; }" , "type 'beff' is not defined");
-  assert_parser_error("main(): i32 { oxi 42; }"     , "expected 'return' keyword but got 'oxi'");
+  // FIXME: once function calls are implemented, this error should inform that
+  // neither a variable or function call was found.
+  assert_parser_error("main(): i32 { oxi 42; }"     , "expected ':' but got 'TOKEN_NUMBER'");
 
   return MUNIT_OK;
 }
 
 static MunitTest tests[] = {
   { "/test_parse_function", test_parse_function, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
+  { "/test_parse_function", test_parse_function, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
   { "/test_parse_basic_syntax_errors", test_parse_basic_syntax_errors, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
   { "/test_parse_arithmetic_expression", test_parse_arithmetic_expression, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
+  { "/test_parse_arithmetic_expression", test_parse_arithmetic_expression, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
+  { "/test_parse_variable_definition", test_parse_variable_definition, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
   { NULL, NULL, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL }
 };