Function _Validate_pattern_comprehension

src/ast/ast_validations.c:398–460

validate a pattern comprehension

// validate a pattern comprehension
static VISITOR_STRATEGY _Validate_pattern_comprehension
(
	const cypher_astnode_t *n,  // ast-node
	bool start,                 // first traversal
	ast_visitor *visitor        // visitor
) {
	validations_ctx *vctx = AST_Visitor_GetContext(visitor);

	// we enter ONLY when start=true, so no check is needed

	const cypher_astnode_t *id = cypher_ast_pattern_comprehension_get_identifier(n);
	bool is_new;
	const char *identifier;
	if(id) {
		identifier = cypher_ast_identifier_get_name(id);
		is_new = (raxFind(vctx->defined_identifiers, (unsigned char *)identifier, strlen(identifier)) == raxNotFound);
	}
	else {
		is_new = false;
	}

	// Introduce local identifier if it is not yet introduced
	if(is_new) {
		raxInsert(vctx->defined_identifiers, (unsigned char *)identifier, strlen(identifier), NULL, NULL);
	}

	// Visit expression-children
	// Visit pattern
	const cypher_astnode_t *pattern = cypher_ast_pattern_comprehension_get_pattern(n);
	if(pattern) {
		AST_Visitor_visit(pattern, visitor);
		if(ErrorCtx_EncounteredError()) {
			return VISITOR_BREAK;
		}
	}

	// Visit predicate
	const cypher_astnode_t *pred = cypher_ast_pattern_comprehension_get_predicate(n);
	if(pred) {
		AST_Visitor_visit(pred, visitor);
		if(ErrorCtx_EncounteredError()) {
			return VISITOR_BREAK;
		}
	}

	// Visit eval
	const cypher_astnode_t *eval = cypher_ast_pattern_comprehension_get_eval(n);
	if(eval) {
		AST_Visitor_visit(eval, visitor);
		if(ErrorCtx_EncounteredError()) {
			return VISITOR_BREAK;
		}
	}

	// pattern comprehension identifier is no longer bound, remove it from bound vars
	// if it was introduced
	if(is_new) {
		raxRemove(vctx->defined_identifiers, (unsigned char *)identifier, strlen(identifier), NULL);