elisp.js/el/primitives.js

133 lines
3.6 KiB
JavaScript

////
// Emacs Lisp implementation in JavaScript.
//
// Copyright (c) 2009 Sami Samhuri - sami.samhuri@gmail.com
//
// Released under the terms of the MIT license. See the included file
// LICENSE.
/****************************************************************
**** Primitives ************************************************
****************************************************************/
EL.PrimitiveVariables = [
['t', {
type: 'variable',
value: ['symbol', 't'],
docstring: "true"
}],
['nil', {
type: 'variable',
value: ['symbol', 'nil'],
docstring: "nil"
}]
];
// 'this' is bound to the EL.Evaluator object
EL.PrimitiveFunctions = [
['symbol-name', {
type: 'primitive',
name: 'symbol-name',
params: ['symbol'],
body: function(symbol) { return EL.string(EL.val(symbol)); },
docstring: "Return a symbol's name, a string."
}],
['string-match', {
type: 'primitive',
name: 'string-match',
params: ['regex', 'string', '&optional', 'start'],
body: function(regex, string, start) {
var index = start ? EL.val(start) : 0,
s = EL.val(string).substring(index),
match = s.match(new RegExp(EL.val(regex))),
found = match ? EL.number(s.indexOf(match[0])) : EL.nil;
return found;
},
docstring: "Return the index of the char matching regex in string, beginning from start if available."
}],
['+', {
type: 'primitive',
name: '+',
params: [/* ... */],
body: function() {
var args = EL.Util.shallowCopy(arguments),
initial = EL.inferType(args),
type = initial[0];
return EL.Util.reduce(function(sum, n) {
return [type, EL.val(sum) + EL.val(n)];
}, initial, args);
},
docstring: "add two numbers"
}],
['-', {
type: 'primitive',
name: '-',
params: [/* ... */],
body: function() {
return EL.Util.foldr(function(diff, n) {
return EL.number(EL.val(diff) - EL.val(n));
}, EL.number(0), EL.Util.shallowCopy(arguments));
},
docstring: "subtract two numbers"
}],
['*', {
type: 'primitive',
name: '*',
params: [/* ... */],
body: function() {
return EL.Util.reduce(function(prod, n) {
return EL.number(EL.val(prod) * EL.val(n));
}, EL.number(1), EL.Util.shallowCopy(arguments));
},
docstring: "multiply two numbers"
}],
['/', {
type: 'primitive',
name: '/',
params: [/* ... */],
body: function() {
return EL.Util.foldr(function(quot, n) {
return EL.number(EL.val(quot) / EL.val(n));
}, EL.number(1), EL.Util.shallowCopy(arguments));
},
docstring: "divide two numbers"
}],
['print', {
type: 'primitive',
name: 'print',
params: ['x'],
body: function(x, tostring) {
var buffer = "",
tag = EL.tag(x);
function p(s) {
if (tostring) buffer += s;
else print(s);
}
if (tag == 'number' || tag == 'symbol' || tag == 'string') {
p(EL.val(x));
}
else if (tag == 'lambda') {
var fn = EL.val(x);
p('(lambda ' + fn.name + ' (' + fn.params + ')\n');
p(fn.body); // TODO lisp pretty print
p(')');
}
else if (tag == 'list') {
var recurse = arguments.callee; // far easier to remember than Y
print('(', El.val(x).map(function(e){return (recurse(e, true) + ' ');}), ")");
}
else {
print('unknown type: ' + x);
}
return EL.nil;
},
docstring: "print an expression"
}]
];
/****************************************************************
****************************************************************/