convertParams.js

// Converts parameters serialized with WebPPL prior to PR #837 so that
// they work with more recent versions.

// https://github.com/probmods/webppl/pull/837

// Output is written to standard out and can be redirected to a file
// as required. For example:

// node convertParams.js old.json > new.json

var fs = require('fs');

var argv = process.argv;

if (argv.length < 3) {
  console.log('Usage: node convertParams.js <json-parameter-file>');
  process.exit();
}

var inFilename = argv[2];

try {
  var inData = JSON.parse(fs.readFileSync(inFilename));
  console.warn('Processing ' + inFilename + '...');
} catch (e) {
  console.warn('Error reading ' + inFilename);
  process.exit();
}

var outData = {};
for (var k in inData) {
  var arr = inData[k];
  if (!Array.isArray(arr) || arr.length !== 1) {
    throw new Error('Unexpected input, cannot convert these parameters.');
  }
  outData[k] = arr[0];
}

console.log(JSON.stringify(outData));