lang: ast: replace var keyword with global

local variables are now created automatically when they are first assigned to. the global keyword can be used to declare that a name refers to a global variable instead, at which point, assigning to the name results in the assignment referencing the global variable instead of allocating a new global variable.
2025-09-08 15:50:50 +01:00
parent 5ea544692b
commit 84e52b1649
5 changed files with 39 additions and 41 deletions
--- a/lang/ast/global.c
+++ b/lang/ast/global.c
@@ -0,0 +1,134 @@
+#include "ctx.h"
+#include "expr/expr.h"
+#include "iterate.h"
+#include "node.h"
+
+#include <ivy/lang/ast.h>
+
+struct global_parser_state {
+	struct parser_state s_base;
+	unsigned int s_prev_token;
+};
+
+static void init_state(struct ivy_parser *ctx, struct parser_state *sp, uintptr_t arg)
+{
+	struct global_parser_state *state = (struct global_parser_state *)sp;
+	state->s_prev_token = IVY_KW_GLOBAL;
+}
+
+struct token_parse_result parse_ident(struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct global_parser_state *state
+		= parser_get_state(ctx, struct global_parser_state);
+	if (state->s_prev_token != IVY_KW_GLOBAL) {
+		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
+	}
+
+	struct expr_parser_state *ident_parse
+		= (struct expr_parser_state *)parser_push_state(
+			ctx, IVY_AST_EXPR, 0);
+	expr_add_terminator(ident_parse, IVY_SYM_EQUAL);
+	expr_add_terminator(ident_parse, IVY_SYM_DOT);
+	return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
+}
+
+struct token_parse_result parse_left_paren(
+	struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct global_parser_state *state
+		= parser_get_state(ctx, struct global_parser_state);
+
+	if (state->s_prev_token != IVY_KW_GLOBAL) {
+		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
+	}
+
+	struct expr_parser_state *tuple_ident_parse
+		= (struct expr_parser_state *)parser_push_state(
+			ctx, IVY_AST_EXPR, 0);
+	expr_add_terminator(tuple_ident_parse, IVY_SYM_EQUAL);
+	return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
+}
+
+struct token_parse_result parse_equal(struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct global_parser_state *state
+		= parser_get_state(ctx, struct global_parser_state);
+	struct ivy_ast_global_node *global
+		= (struct ivy_ast_global_node *)state->s_base.s_node;
+	if (!global->n_left) {
+		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
+	}
+
+	state->s_prev_token = IVY_SYM_EQUAL;
+
+	struct expr_parser_state *val_parse
+		= (struct expr_parser_state *)parser_push_state(
+			ctx, IVY_AST_EXPR, 0);
+	expr_add_terminator(val_parse, IVY_SYM_DOT);
+	return PARSE_RESULT(IVY_OK, 0);
+}
+
+struct token_parse_result parse_dot(struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
+	return PARSE_RESULT(IVY_OK, 0);
+}
+
+static enum ivy_status add_child(
+	struct parser_state *parent, struct ivy_ast_node *child)
+{
+	struct global_parser_state *state = (struct global_parser_state *)parent;
+	struct ivy_ast_global_node *global
+		= (struct ivy_ast_global_node *)parent->s_node;
+
+	switch (state->s_prev_token) {
+	case IVY_KW_GLOBAL:
+		if (global->n_left) {
+			return IVY_ERR_BAD_SYNTAX;
+		}
+
+		global->n_left = child;
+		break;
+	case IVY_SYM_EQUAL:
+		if (global->n_val) {
+			return IVY_ERR_BAD_SYNTAX;
+		}
+
+		global->n_val = child;
+		break;
+	default:
+		return IVY_ERR_BAD_SYNTAX;
+	}
+
+	return IVY_OK;
+}
+
+static void collect_children(
+	struct ivy_ast_node *node, struct ivy_ast_node_iterator *iterator)
+{
+	struct ivy_ast_global_node *global = (struct ivy_ast_global_node *)node;
+
+	if (global->n_left) {
+		ast_node_iterator_enqueue_node(iterator, node, global->n_left);
+	}
+
+	if (global->n_val) {
+		ast_node_iterator_enqueue_node(iterator, node, global->n_val);
+	}
+}
+
+struct ast_node_type global_node_ops = {
+	.n_add_child = add_child,
+	.n_collect_children = collect_children,
+	.n_state_size = sizeof(struct global_parser_state),
+	.n_node_size = sizeof(struct ivy_ast_global_node),
+	.n_init_state = init_state,
+	.n_token_parsers = {
+		TOK_PARSER(IDENT, parse_ident),
+	},
+	.n_symbol_parsers = {
+		SYM_PARSER(LEFT_PAREN, parse_left_paren),
+		SYM_PARSER(EQUAL, parse_equal),
+		SYM_PARSER(DOT, parse_dot),
+	},
+};