pegjs: Inconsistent behaviour of generated parser

Issue type

• Bug Report:

Prerequisites

• Can you reproduce the issue?: yes
• Did you search the repository issues?: yes
• Did you check the forums?: no
• Did you perform a web search (google, yahoo, etc)?: yes

Description

At the moment I’m using the JS API to generate the parser on runtime. This works fine.

I then tried to generate the parser using the CLI, to avoid generating it during runtime. When I use it though I get errors (~half of my tests for parsing the string throw errors).

Steps to Reproduce

1. Move the grammar into its own file grammar.pegjs
2. Generate the parser using the CLI

pegjs -o parser.js grammar.pegjs

1. Remove the peg.generate('...') and replace it with the new parser

const parser = require('./parser');
parser.parse('...');

1. Run the tests

Expected behavior: I would expect that the generated parser from the CLI works the same as the generated parser from the JS API.

Actual behavior: Using the JS API, when I pass this string ('foo = "bar"') to the parser I get the following AST:

{
  kind: 'condition',
  target: 'foo',
  operator: '=',
  value: 'bar',
  valueType: 'string',
  attributeType: undefined
}

However, when I use the “generated” parser using the CLI, and pass the same string ('foo = "bar"') I get the following error:

SyntaxError: Expected "(", boolean, date, datetime, number, string, or time but "\"" found.
    at peg$buildStructuredError (/Users/emmenko/xxx/parser.js:446:12)
    at Object.peg$parse [as parse] (/Users/emmenko/xxx/parser.js:2865:11)
    at repl:1:7
    at ContextifyScript.Script.runInThisContext (vm.js:50:33)
    at REPLServer.defaultEval (repl.js:240:29)
    at bound (domain.js:301:14)
    at REPLServer.runBound [as eval] (domain.js:314:12)
    at REPLServer.onLine (repl.js:441:10)
    at emitOne (events.js:121:20)
    at REPLServer.emit (events.js:211:7) 

Software

• PEG.js: 0.10.0
• Node.js: 8.9.1
• NPM or Yarn: yarn@1.3.2
• Browser: Chrome
• OS: OSX
• Editor: VSCode