Function _Validate_list_comprehension

src/ast/ast_validations.c:340–395

validate a list comprehension

// validate a list comprehension
static VISITOR_STRATEGY _Validate_list_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_list_comprehension_get_identifier(n);
	const char *identifier = cypher_ast_identifier_get_name(id);
	bool is_new = (raxFind(vctx->defined_identifiers, (unsigned char *)identifier, strlen(identifier)) == raxNotFound);

	// 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 expression
	const cypher_astnode_t *exp = cypher_ast_list_comprehension_get_expression(n);
	if(exp) {
		AST_Visitor_visit(exp, visitor);
		if(ErrorCtx_EncounteredError()) {
			return VISITOR_BREAK;
		}
	}

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

	// list 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);
	}

	// do not traverse children
	return VISITOR_CONTINUE;
}

// validate a pattern comprehension