moin

moin is a Monty interpreter implemented in pure Javascript using the parser generator PEG.js. Besides the moco Monty compiler, it is the second attempt to implement the language.

Status

moin is still in development and does not cover the whole language.

Demo

A live demo can be found here

Usage

Since the execution of a Monty program may take some time, the browser window will freeze while the program is interpreted. To avoid that, web workers can be used. Web workers are threads for Javascript. moin is able to automatically detect whether web workers are available. If yes, a web worker thread will be started for the interpretation of the Monty program. If not, the browser window will freeze during execution. The user of the library does not have to care about web workers.

For moin to work properly, the four files moin.js, parser.js, interpreter.js and worker.js must be copied into your project folder. However, only the moin.js file must be included in the HTML file, the other files are loaded dynamically.

<script type="application/javascript" src="moin.js"></script>
<script type="application/javascript">
moin("println(55)");
</script>

First, the script moin.js is included. Then, the function moin is used in order to start the interpreter in a worker thread. The first parameter of the function is a string that contains the input Monty program. The second parameter is an optional options object. The following example shows all possible options:

moin("println(55)", {
    done : function(){},
    print : function(msg){},
    read : function(){return "";},
    err : function(msg){},
    scriptpath : ""
});

Options:

• done A function that is called when the execution of the code is done. It should not take any parameters and have no return value
• print This function will be called when the Monty print or println function is called. You can use it in order to pop up a dialog or write it into an HTML element.
• read This function will be called when the Monty read or readln function is called. It should return a string value.
• err This function will be called when an error occurs.
• scriptpath this parameter specifies where the moin javascript files are located. If omitted, it is assumed that they reside in the same directoy as the HTML document.

License

The MIT license is a very permissive open source license. See the LICENSE file for more information.