ebnf-parser/tests/ebnf_parse.js

A parser for BNF and EBNF grammars used by jison

var assert = require("assert"),
    bnf = require("../ebnf-parser"),
    ebnf = require("../ebnf-transform");

function testParse(top, strings) {
    return function() {
        var expected = {
            "bnf": ebnf.transform({"top": [top]})
        };
        var grammar = "%ebnf\n%%\ntop : "+top+";";
        assert.deepEqual(bnf.parse(grammar), expected);
    };
}

var tests = {
    "test idempotent transform": function() {
        var first = {
            "nodelist": [["", "$$ = [];"], ["nodelist node", "$1.push($2);"]]
        };
        var second = ebnf.transform(JSON.parse(JSON.stringify(first)));
        assert.deepEqual(second, first);
    },
    "test repeat (*) on empty string": testParse("word* EOF", ""),
    "test repeat (*) on single word": testParse("word* EOF", "oneword"),
    "test repeat (*) on multiple words": testParse("word* EOF", "multiple words"),
    "test repeat (+) on single word": testParse("word+ EOF", "oneword"),
    "test repeat (+) on multiple words": testParse("word+ EOF", "multiple words"),
    "test option (?) on empty string": testParse("word? EOF", ""),
    "test option (?) on single word": testParse("word? EOF", "oneword"),
    "test group () on simple phrase": testParse("(word word) EOF", "two words"),
    "test group () with multiple options on first option": testParse("((word word) | word) EOF", "hi there"),
    "test group () with multiple options on second option": testParse("((word word) | word) EOF", "hi"),
    "test complex expression ( *, ?, () )": testParse("(word (',' word)*)? EOF", ["", "hi", "hi, there"])
};

for (var test in tests) {
    exports[test] = tests[test];
}