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pegjs/test/spec/api/plugin-api.spec.js

186 lines
4.6 KiB
JavaScript

"use strict";
const chai = require( "chai" );
const peg = require( "../../../lib/peg" );
const expect = chai.expect;
describe( "plugin API", function () {
describe( "use", function () {
const grammar = "start = 'a'";
it( "is called for each plugin", function () {
const pluginsUsed = [ false, false, false ];
const plugins = [
{ use() {
pluginsUsed[ 0 ] = true;
} },
{ use() {
pluginsUsed[ 1 ] = true;
} },
{ use() {
pluginsUsed[ 2 ] = true;
} }
];
peg.generate( grammar, { plugins: plugins } );
expect( pluginsUsed ).to.deep.equal( [ true, true, true ] );
} );
it( "receives configuration", function () {
const plugin = {
use( config ) {
expect( config ).to.be.an( "object" );
expect( config.parser ).to.be.an( "object" );
expect( config.parser.parse( "start = 'a'" ) ).to.be.an( "object" );
expect( config.passes ).to.be.an( "object" );
expect( config.passes.check ).to.be.an( "array" );
config.passes.check.forEach( pass => {
expect( pass ).to.be.a( "function" );
} );
expect( config.passes.transform ).to.be.an( "array" );
config.passes.transform.forEach( pass => {
expect( pass ).to.be.a( "function" );
} );
expect( config.passes.generate ).to.be.an( "array" );
config.passes.generate.forEach( pass => {
expect( pass ).to.be.a( "function" );
} );
}
};
peg.generate( grammar, { plugins: [ plugin ] } );
} );
it( "receives options", function () {
const generateOptions = {
plugins: [ {
use( config, options ) {
expect( options ).to.equal( generateOptions );
}
} ],
foo: 42
};
peg.generate( grammar, generateOptions );
} );
it( "can replace parser", function () {
const plugin = {
use( config ) {
config.parser = peg.generate( `
start = .* {
return {
type: 'grammar',
rules: [{
type: 'rule',
name: 'start',
expression: {
type: 'literal',
value: text(),
ignoreCase: false
}
}]
};
}
` );
}
};
const parser = peg.generate( "a", { plugins: [ plugin ] } );
expect( parser.parse( "a" ) ).to.equal( "a" );
} );
it( "can change compiler passes", function () {
const plugin = {
use( config ) {
function pass( ast ) {
ast.code = "({ parse: function() { return 42; } })";
}
config.passes.generate = [ pass ];
}
};
const parser = peg.generate( grammar, { plugins: [ plugin ] } );
expect( parser.parse( "a" ) ).to.equal( 42 );
} );
it( "can change options", function () {
const grammar = `
a = 'x'
b = 'x'
c = 'x'
`;
const plugin = {
use( config, options ) {
options.allowedStartRules = [ "b", "c" ];
}
};
const parser = peg.generate( grammar, {
allowedStartRules: [ "a" ],
plugins: [ plugin ]
} );
expect( () => {
parser.parse( "x", { startRule: "a" } );
} ).to.throw();
expect( parser.parse( "x", { startRule: "b" } ) ).to.equal( "x" );
expect( parser.parse( "x", { startRule: "c" } ) ).to.equal( "x" );
} );
} );
} );