scratch-html5/js/primitives/Primitives.js
2013-10-28 20:00:20 +00:00

106 lines
4.4 KiB
JavaScript

// Copyright (C) 2013 Massachusetts Institute of Technology
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License version 2,
// as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
// Scratch HTML5 Player
// Primitives.js
// Tim Mickel, July 2011
// Provides the basic primitives for the interpreter and loads in the more
// complicated primitives, e.g. MotionAndPenPrims.
'use strict';
var Primitives = function() {}
Primitives.prototype.addPrimsTo = function(primTable) {
// Math primitives
primTable["+"] = function(b) { return interp.arg(b, 0) + interp.arg(b, 1) };
primTable["-"] = function(b) { return interp.arg(b, 0) - interp.arg(b, 1) };
primTable["*"] = function(b) { return interp.arg(b, 0) * interp.arg(b, 1) };
primTable["/"] = function(b) { return interp.arg(b, 0) / interp.arg(b, 1) };
primTable["%"] = function(b) { return interp.arg(b, 0) % interp.arg(b, 1) };
primTable["randomFrom:to:"] = this.primRandom;
primTable["<"] = function(b) { return (interp.arg(b, 0) < interp.arg(b, 1)) };
primTable["="] = function(b) { return (interp.arg(b, 0) == interp.arg(b, 1)) };
primTable[">"] = function(b) { return (interp.arg(b, 0) > interp.arg(b, 1)) };
primTable["&"] = function(b) { return interp.arg(b, 0) && interp.arg(b, 1) };
primTable["|"] = function(b) { return interp.arg(b, 0) || interp.arg(b, 1) };
primTable["not"] = function(b) { return !interp.arg(b, 0) };
primTable["abs"] = function(b) { return Math.abs(interp.arg(b, 0)) };
primTable["sqrt"] = function(b) { return Math.sqrt(interp.arg(b, 0)) };
primTable["\\\\"] = this.primModulo;
primTable["rounded"] = function(b) { return Math.round(interp.arg(b, 0)) };
primTable["computeFunction:of:"] = this.primMathFunction;
// String primitives
primTable["concatenate:with:"] = function(b) { return "" + interp.arg(b, 0) + interp.arg(b, 1) };
primTable["letter:of:"] = this.primLetterOf;
primTable["stringLength:"] = function(b) { return interp.arg(b, 0).length };
new VarListPrims().addPrimsTo(primTable);
new MotionAndPenPrims().addPrimsTo(primTable);
new LooksPrims().addPrimsTo(primTable);
new SensingPrims().addPrimsTo(primTable);
new SoundPrims().addPrimsTo(primTable);
}
Primitives.prototype.primRandom = function(b) {
var n1 = interp.arg(b, 0);
var n2 = interp.arg(b, 1);
var low = (n1 <= n2) ? n1 : n2;
var hi = (n1 <= n2) ? n2 : n1;
if(low == hi) return low;
// if both low and hi are ints, truncate the result to an int
if ((Math.floor(low) == low) && (Math.floor(hi) == hi)) {
return low + Math.floor(Math.random() * ((hi + 1) - low));
}
return (Math.random() * (hi - low)) + low;
}
Primitives.prototype.primLetterOf = function(b) {
var s = interp.arg(b, 1);
var i = interp.arg(b, 0) - 1;
if ((i < 0) || (i >= s.length)) return "";
return s.charAt(i);
}
Primitives.prototype.primModulo = function(b) {
var modulus = interp.arg(b, 1);
var n = interp.arg(b, 0) % modulus;
if (n < 0) n += modulus;
return n;
}
Primitives.prototype.primMathFunction = function(b) {
var op = interp.arg(b, 0);
var n = interp.arg(b, 1);
switch(op) {
case "abs": return Math.abs(n);
case "sqrt": return Math.sqrt(n);
case "sin": return Math.sin((Math.PI * n) / 180);
case "cos": return Math.cos((Math.PI * n) / 180);
case "tan": return Math.tan((Math.PI * n) / 180);
case "asin": return (Math.asin(n) * 180) / Math.PI;
case "acos": return (Math.acos(n) * 180) / Math.PI;
case "atan": return (Math.atan(n) * 180) / Math.PI;
case "ln": return Math.log(n);
case "log": return Math.log(n) / Math.LN10;
case "e ^": return Math.exp(n);
case "10 ^": return Math.exp(n * Math.LN10);
}
return 0;
}