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Universal Lambda Machine: Difference between revisions
Add universal lambda machine in JavaScript
imported>Tromp (Add universal lambda machine in Python) |
imported>Tromp (Add universal lambda machine in JavaScript) |
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</syntaxhighlight>
=={{header|JavaScript}}==
</syntaxhighlight lang="javascript">#!/usr/local/bin/node --stack-size=8192
let bytemode = process.argv.length <= 2;
var data;
var nchar = 0;
var nbit = 0;
var progchar;
function bit2lam(bit) {
return function(x0) { return function(x1) { return bit ? x1 : x0 } }
}
function byte2lam(bits,n) {
return n==0 ? (function(_) { return function(y) { return y } }) // nil
: (function(z) { return z (bit2lam((bits>>(n-1))&1))
(byte2lam(bits,n-1)) }) // cons bitn bits>n
}
function input(n) { // input from n'th character onward
if (n >= data.length)
return function(z) { { return function(y) { return y } } } // nil
let c = data[n];
return function(z) { return z (bytemode ? byte2lam(c,8) : bit2lam(c&1)) (input(n+1)) } // cons charn chars>n
}
function lam2bit(lambit) {
return lambit(function(_){return 0})(function(_){return 1})() // force suspension
}
function lam2byte(lambits, x) {
return lambits(function(lambit) {
return function(lamtail) {
return function(_) { return lam2byte(lamtail, 2*x + lam2bit(lambit)) }
}
})(Buffer.from([x])) // end of byte
}
function output(prog) {
return prog(function(c) { // more chars
process.stdout.write(bytemode ? lam2byte(c,0) : lam2bit(c) ? '1' : '0');
return function(tail) {
return function(_) { return output(tail) }
}
})(0) // end of output
}
function getbit() {
if (nbit==0) {
progchar = data[nchar++];
nbit = bytemode ? 8 : 1;
}
return (progchar >> --nbit) & 1;
}
function program() {
if (getbit()) { // variable
var i = 0;
while (getbit()==1) { i++ }
return function() { return arguments[i] }
} else if (getbit()) { // application
let p = program();
let q = program();
return function(...args) {
return p(...args)(function(arg) { return q(...args)(arg) }) // suspend argument
}
} else {
let p = program();
return function(...args) {
return function(arg) { return p(arg, ...args) } // extend environment with one more argument
}
}
}
process.stdin.on('readable', () => {
if ((data = process.stdin.read()) != null) {
prog = program()();
output(prog(input(nchar))) // run program with empty env on input
}
});</syntaxhighlight>
=={{header|Python}}==
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