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pegjs/lib/compiler/passes/report-missing-rules.js

47 lines
1.2 KiB
JavaScript

var utils = require("../../utils"),
GrammarError = require("../../grammar-error");
/* Checks that all referenced rules exist. */
module.exports = function(ast) {
function nop() {}
function checkExpression(node) { check(node.expression); }
function checkSubnodes(propertyName) {
return function(node) { utils.each(node[propertyName], check); };
}
var check = utils.buildNodeVisitor({
grammar: checkSubnodes("rules"),
rule: checkExpression,
named: checkExpression,
choice: checkSubnodes("alternatives"),
action: checkExpression,
sequence: checkSubnodes("elements"),
labeled: checkExpression,
text: checkExpression,
simple_and: checkExpression,
simple_not: checkExpression,
semantic_and: nop,
semantic_not: nop,
optional: checkExpression,
zero_or_more: checkExpression,
one_or_more: checkExpression,
rule_ref:
function(node) {
if (!utils.findRuleByName(ast, node.name)) {
throw new GrammarError(
"Referenced rule \"" + node.name + "\" does not exist."
);
}
},
literal: nop,
"class": nop,
any: nop
});
check(ast);
};