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α-wwwiki :: history/psil/20130619-170005.txt

editor : alpha [82.253.220.49] 2013/06/19 17:00:05
_h1 psil
_p I just discover a smart code found on Github : [[psil|https://gist.github.com/pabloPXL/1679611]]. Written by [[Pablo Vidal|https://github.com/pabloPXL]].

{pre {@ id="output"}}
{input {@ type="submit" value="Click on me !" onclick="°°

// start parser
function extcx(ar,cx){
  return ar.reduce(function(o, kv){ o[kv[0]] = kv[1]; return o; },cx || {})
}
function zip(ar1, ar2){
  return ar1.reduce(function(ar, v1, i1){ if (ar2[i1]) ar.push([v1,ar2[i1]]); return ar; },[])
}
function atomp(a){ 
  return !(typeof a in {object:0,array:0}) 
}
function lazyp(a){ 
  return (a in {cond:0,quote:0,lambda:0}) 
}

// start dictionary / global environment
function env(){
  var inst  = this;
  inst.atom = function(a){ return atomp(a) };
  inst.set  = function(as){ return inst[as[0]] = as[1] };
  inst.quote = function(as){ return as[0] };
  inst.fst  = function(as){ return as[0][0] };
  inst.rst  = function(as){ return as[0].slice(1) };
  inst.cons = function(as){ return [as[0]].concat(as[1]) };
  inst.eq   = function(as){ return as[0] === as[1] };
  inst.cond = function(as,cx){ 
    return leval(as[0],cx) ? leval(as[1],cx) : leval(as[2],cx) 
  };

inst['++'] = function(as){ as[0] = as[0] + 1; return as[0] };
  inst['--'] = function(as){ as[0] = as[0] - 1; return as[0] };
  inst['*'] = function(as){ 
    for (var i=0, p=1; i< as.length; i++) p *= as[i];
    return p;
  };

var mathfns = 
  ['abs', 'acos', 'asin', 'atan', 'atan2', 'ceil', 'cos', 'exp', 
  'floor', 'log', 'max', 'min', 'random', 'round', 'sin', 'sqrt', 'tan'];
  for (var i=0; i< mathfns.length; i++)
    inst[mathfns[i]] = function( tag ) { 
      return function (as) { return Math[tag](as[0]); } }(mathfns[i]);

return inst;
}
// end dictionary / global environment

// end parser

// start test
function psil () {
  var cx = new env;
  var str = ''
+ '\n[set,a,42] -> ' + leval(['set','a',42],cx)
+ '\na -> ' + leval('a',cx)
+ '\n[eq,42,a] -> ' + leval(['eq',42,'a'],cx)
+ '\n[quote,[1,2]] -> ' + leval(['quote',[1,2]],cx)
+ '\n[fst,[quote,[1,2]]] -> ' + leval(['fst',['quote',[1,2]]],cx)
+ '\n[rst,[quote,[1,2]]] -> ' + leval(['rst',['quote',[1,2]]],cx)
+ '\n[cons,1,[quote,[2,3]]] -> ' + leval(['cons',1,['quote',[2,3]]],cx)
+ '\n[cond,[eq,1,2],42,43] -> ' + leval(['cond',['eq',1,2],42,43],cx)
+ '\n[atom,[quote,[1,2]]] -> ' + leval(['atom',['quote',[1,2]]],cx)
+ '\n[set,second,[quote,[lambda,[x],[fst,[rst,x]]]]] -> ' 
+ leval(['set','second',['quote',['lambda',['x'],['fst',['rst','x']]]]],cx)
+ '\n[second,[quote,[1,2,3]]] -> ' + leval(['second',['quote',[1,2,3]]],cx)
+ '\n'
+ '\n[set,y,10] -> ' + leval(['set','y',10],cx)
+ '\n[set,z,11] -> ' + leval(['set','z',11],cx)
+ '\n[cond,[eq,y,z],true,false] -> ' + leval(['cond',['eq','y','z'],true,false],cx)
+ '\n[++,10] -> ' + leval(['++',10],cx)
+ '\n[--,10] -> ' + leval(['--',10],cx)
+ '\n[*,1,2,3,4,5,6] -> ' + leval(['*',1,2,3,4,5,6],cx)
+ '\n[set,cubic,[quote,[lambda,[x],[*,x,x,x]]]] -> ' 
+ leval( ['set','cubic',['quote',['lambda',['x'],['*','x','x','x']]]],cx)
+ '\n[cubic,4] -> ' + leval(['cubic',4],cx)
+ '\n[sqrt,2] -> ' + leval(['sqrt',2],cx)
+ '\n[exp,1] -> ' + leval(['exp',1],cx)

+ '\n'
+ '\nbut factorial : '
+ '\n[set,fac,[quote,[lambda,[x],[cond,[eq,x,0],1,[*,[x],[fac,[--,x]]]]]]]'

+ '\n' + leval( 
  ['set','fac',
    ['quote',
      ['lambda',['x'], 
        ['cond', 
          ['eq','x',0],
            1, 
            ['*', 
            ['x'], 
            ['fac', ['--','x'] ]       
          ]    
        ]       
      ]
    ]
  ]
  ,cx) 
  
+ '\n[fac,6] -> TypeError: ar1 is undefined ?'  // + leval(['fac',6],cx)

return str;
}

getId('output').innerHTML = psil();
°°"}}
_p A lot to learn. More to come ...