Function _AST_GetWithAliases

src/ast/ast_validations.c:107–153

introduce aliases of a WITH clause to the bound vars return true if no errors where encountered, false otherwise

// introduce aliases of a WITH clause to the bound vars
// return true if no errors where encountered, false otherwise
static bool _AST_GetWithAliases
(
	const cypher_astnode_t *node,  // ast-node from which to retrieve the aliases
	rax *aliases                   // rax to which to insert the aliases
) {
	if(!node || (cypher_astnode_type(node) != CYPHER_AST_WITH)) {
		return false;
	}

	// local env to check for duplicate column names
	rax *local_env = raxNew();

	// traverse the projections
	uint num_with_projections = cypher_ast_with_nprojections(node);
	for(uint i = 0; i < num_with_projections; i ++) {
		const cypher_astnode_t *child = cypher_ast_with_get_projection(node, i);
		const cypher_astnode_t *alias_node = cypher_ast_projection_get_alias(child);
		const char *alias;
		if(alias_node) {
			// Retrieve "a" from "WITH [1, 2, 3] as a"
			alias = cypher_ast_identifier_get_name(alias_node);
		} else {
			// Retrieve "a" from "WITH a"
			const cypher_astnode_t *expr = cypher_ast_projection_get_expression(child);
			if(cypher_astnode_type(expr) != CYPHER_AST_IDENTIFIER) {
				ErrorCtx_SetError("WITH clause projections must be aliased");
				raxFree(local_env);
				return false;	
			}
			alias = cypher_ast_identifier_get_name(expr);
		}
		raxInsert(aliases, (unsigned char *)alias, strlen(alias), NULL, NULL);

		// check for duplicate column names (other than internal representation
		// of outer-context variables)
		if(raxTryInsert(local_env, (unsigned char *)alias, strlen(alias), NULL,
			NULL) == 0 &&
			alias[0] != '@') {
				ErrorCtx_SetError("Error: Multiple result columns with the same name are not supported.");
				raxFree(local_env);
				return false;
		}
	}

	raxFree(local_env);
	return true;
}

// Extract identifiers / aliases from a procedure call.
static void _AST_GetProcCallAliases