JSForth

This is a Forth implementation in Javascript, with a REPL using xterm.js. It started out as a student's college assignment; it only took a few hours to throw together, so it's still very much a "work in progress". That said, it is pretty darn cool! See manual.html for the list of supported words, known bugs, and other fun stuff. You can try it here.

Change log

• Version 0.2: Added variables, constants, a memory map, and over 3 dozen new words
• Version 0.1: Initial release; it had if/then, do/loop, : and ; and about a dozen other words.

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From here on down, it's all just low-level notes about the current project status; unless you're a programmer interested in contributing (and please, by all means do) there probably isn't much here of interest.

Ideas / wish list for 0.3

• ELSE; that will enable a bunch of other words
• BEGIN and AGAIN
• KEY and ?KEY if possible... like I said, maybe ONKEY is better... i.e. ONKEY MYCALLBACK
• Known bug, no obvious solution, fight for another night: in ." and s", for reasons only God and the original dev would understand, if running inside a user-defined word, the last word get treated like a Forth word. For example:

: test ." This is an example." ;
\ If I run my "test" word, it sees 'example."' as a word to be interpreted.  Since it's not in the dictionary, it shows an error.
\ Sense?  We don't need to make no steenkin' sense! :P #BugInTheJavaScript
\ https://www.youtube.com/watch?v=vINkWUe874c

• Multi-line definitions; i.e.

: myWord
	." Oh my word :D"
	cr
	." Oh wait, this wouldn't compile anyway till that bug is fixed"
;

• I"d also kinda like a nice editor for files in localStorage; probably not gonna build one in the terminal; I'm thinking a fancy one with something like CodeMirror :)
• Once I've got that, add INCLUDE (with support for URLs instead of just "files" in localStorage)
• Canvas, audio, gamepad, speech... these will probably be scripts and not built into the language itself, but still... if possible, would be nice.
• Any harder-to-add standard words, maybe some of the ones in "core extensions" (and also strings etc.).
• C@, C! and CMOVE; these would require a major rework of how the program reads and writes memory. For example, here's what it would take to get c! to work:

var bits = memory[1].toString(2);				// The number as a string in binary format
while (bits.length < 32) bits = "0" + bits;		// Make sure it has 32 characters
var test = 255;									// This the 8-bit number to be stored
test = test.toString(2);						// Convert that to a binary string
var whichByte = 0;								// This is where we get into tricky territory.  if I do i.e. "myVar 1 + c!" it wouldn't work - it would go to the first byte of (myvar + 1 CELL)

// With that sorted, the rest is pretty easy... but getting there would be a PITA.
// memoryPointer would have to be dividied by... 4?... before it could do anything.
// Yeah, that can wait for 0.3 :)

console.log(bits);
if (whichByte == 3)
    bits = test + bits.substr(8);
else if (whichByte == 2)
    bits = bits.substr(0, 8) + test + bits.substr(0, 16);
else if (whichByte == 1)
    bits = bits.substr(0, 16) + test + bits.substr(0, 8);
else bits = bits.substr(0, 24) + test;
console.log(bits);
memory[1] = parseInt(bits, 2);