lang: ast: implement parsing of inline and standalone if-else statements

lang/ast/expr/stmt.c

@@ -0,0 +1,79 @@
+#include "../node.h"
+#include "expr.h"
+#include "../cond.h"
+
+#include <blue/object/string.h>
+#include <ivy/lang/lex.h>
+#include <ivy/lang/operator.h>
+#include <stdio.h>
+
+struct token_parse_result stmt_parse_if(
+	struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct expr_parser_state *state
+		= parser_get_state(ctx, struct expr_parser_state);
+
+	if (state->s_sub_type == EXPR_SUBTYPE_KEYWORD_ARG) {
+		/* keyword messages have a higher precedence than inline conditionals, so
+		 * treat this as a statement terminator. */
+		struct token_parse_result result
+			= expr_finalise_and_return(ctx, state);
+		result.r_flags |= PARSE_REPEAT_TOKEN;
+		return result;
+	}
+
+	struct ivy_ast_node *expr = NULL;
+	struct token_parse_result result
+		= expr_finalise(ctx, state, IVY_PRECEDENCE_IF_ELSE, &expr);
+	if (result.r_status != IVY_OK) {
+		return result;
+	}
+
+	state->s_prev_token = IVY_KW_IF;
+
+	if (b_queue_empty(&state->s_operator_stack) && b_queue_empty(&state->s_output_queue)) {
+		parser_pop_state(ctx, 0);
+	}
+
+	struct cond_group_parser_state *cond
+		= (struct cond_group_parser_state *)parser_push_state(
+			ctx, IVY_AST_COND_GROUP, 0);
+
+	/* if expr is NULL, this is an if-then-else-end statement,
+	 * otherwise, this is an expr-if-else-expr. */
+	cond->s_prev_node = expr;
+	return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
+}
+
+struct token_parse_result stmt_parse_then(
+	struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct expr_parser_state *state
+		= parser_get_state(ctx, struct expr_parser_state);
+	/* treat this as a statement terminator. */
+	struct token_parse_result result = expr_finalise_and_return(ctx, state);
+	result.r_flags |= PARSE_REPEAT_TOKEN;
+	return result;
+}
+
+struct token_parse_result stmt_parse_else(
+	struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct expr_parser_state *state
+		= parser_get_state(ctx, struct expr_parser_state);
+	/* treat this as a statement terminator. */
+	struct token_parse_result result = expr_finalise_and_return(ctx, state);
+	result.r_flags |= PARSE_REPEAT_TOKEN;
+	return result;
+}
+
+struct token_parse_result stmt_parse_end(
+	struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct expr_parser_state *state
+		= parser_get_state(ctx, struct expr_parser_state);
+	/* treat this as a statement terminator. */
+	struct token_parse_result result = expr_finalise_and_return(ctx, state);
+	result.r_flags |= PARSE_REPEAT_TOKEN;
+	return result;
+}