Named Curry

namedCurry.js

var R = require('./ramda');

// Discussion at https://github.com/ramda/ramda/issues/1258

var namedCurry = function(fn, argNames) {
  // TODO: what if fn.length != argNames.length?
  var f = R.curryN(fn.length, function() {
      return fn.apply(this, arguments);
  });
  f['secret-sauce'] = {
    argNames: argNames
  }
  return f;
};
 
var configure = (function() {
  var makeArgs = function(inputArgs, argNames, config) {
    var idx = 0;
    var outputArgs = [];
    R.forEach(function(argName) {
      if (argName in config) {
        outputArgs.push(config[argName]);
      } else {
        outputArgs.push(inputArgs[idx]);
        idx += 1;
        // TODO: proper bounds checking.
      }
    }, argNames);
    return outputArgs;
  };
 
  return function(fn, props) {
    var sauce = fn['secret-sauce'];
    if (!sauce) {
      throw TypeError('Configure called on function without secret sauce');
    }
    var config = R.merge(sauce.config ? sauce.config : {}, props);
    var argNames = sauce.argNames;
    var unassigned = R.difference(argNames, R.keys(config)).length;
    // TODO: what if unassigned is 0? Does this return value or thunk?
    var f = R.curryN(unassigned, function() {
      return fn.apply(this, makeArgs(arguments, argNames, config));
    });
    f['secret-sauce'] = {
      names: argNames,
      config: config
    };
    return f;
  };
}());
 
 
var render = function(controller, view, renderImmediately) {
  return 'v:' + view + ', c: ' + controller + ', ' + (renderImmediately ? 'now' : 'later');
};
 
var namedRender = namedCurry(render, ['ctrl', 'view', 'immediate']);
 
var modalSignup = configure(namedRender, {
  ctrl: 'modal',
  view: 'signup form'
});

var login = configure(namedRender, {
  view: 'login form'
});

var modalLogin = login('modal');
 
 
render('c1', 'v1', true); //=> "v:navigation-icons, c: sidebar, now"
namedRender('c2', 'v2', false); //=> "v:navigation-icons, c: sidebar, later"
modalSignup(true); //=> "v:signup form, c: modal, now"
login('normal', false); //=> "v:login form, c: normal, later"
modalLogin(true); //=> "v:login form, c: modal, now"