yaml-plus

test.yml

    5x: ~"x".repeat(5)~
    1+2: ~1+2~
    dirname: ~__dirname~
    filename: ~__filename~

app.js

var YP = require('yaml-plus')

console.log( YP.parse("x: ~10**2~") )
// {"x": 100}

console.log( YP.parseFile('./test.yml') )
// { "5x": "xxxxx", "1+2": 3,  "dirname": "." , "filename": "test.yml" }