Example of how to use PEG.js

问题

I'm playing around with PEG.js.

I created some simple code that accepts inputs in the form [LettersNumbers]:

abc123
hello98765
etc.

This is the code:

start = expression 

expression = text + number

text = 
a: [a-z]+
{return a.join("");}

number = 
b:[0-9]+
{return b.join("");}

Here: Online version the code can be tested and the parser downloaded, additionally I downloaded peg.js itself.

Unfortunately, the documentation is very sparse. I tried:

<script src="peg-0.9.0.min.js"></script>
<script src="parser.js"></script>
<script>
var parser = new PEG;
parser.parse("test123");
</script>

But got these errors:

Uncaught ReferenceError: module is not defined
Uncaught TypeError: PEG is not a function

Could anybody please provide me with a working example? I just need to integrate the generated js-files into a website.

回答1:

This answer assumes that you would like to continue using the PEG.js online version to build your parser.

You only need peg-0.9.0.min.js if you are generating the parser in your web page. Since you are using the PEG.js online version to generate your parser you don't need to do that.

You do need to include the downloaded parser.js. You need to specify a browser-friendly global variable in the PEG.js web version and re-download.

This example uses PARSER:

Following that you can use:

<script src="parser.js"></script>
<script>
PARSER.parse("test123");
</script>

Plunker example

回答2:

If you want to use it on web, you need to download the browser version, or ref it from CDN.

Also, you need to use its javascriptAPI to create a parser.

// One line version of your grammer.
var parser = PEG.buildParser('start = expression;expression = text + number;text = a: [a-z]+{return a.join("");};number = b:[0-9]+{return b.join("");}');

console.log(parser.parse("test123"));

<script src="https://cdnjs.cloudflare.com/ajax/libs/pegjs/0.7.0/peg.min.js"></script>

来源：https://stackoverflow.com/questions/33417367/example-of-how-to-use-peg-js

标签

javascript

peg

pegjs