An Emoji-based stack language

Synopsis

Instead of standard Forth…

: factorial 0 swap begin dup 1 - dup  1 = until begin * over 0 = until swap drop ;

5 factorial .

>> 120 

In HeartForth…

0110

5

>> 120

Source

Github link

Discussion

HeartForth is a dialect of Forth, a stack-based language. Where other programming languages use many data structures, Forth has a wealth of operators to manipulate the stack. Emoji also has a large number of symbols which incorporate hearts, so these are matched together. So far I have implemented the basics:

HeartForth	Standard Forth	meaning
	dup	( a -> a a )
	drop	( a -> )
	over	( a b -> a b a )
	rot	( a b c -> b c a )
	swap	( a b -> b a )
	.	show last item on stack
	dump	show entire stack

Advantages

• Extremely compact. Many complex programs fit in a tweet.
• Clean visual separation between program and data. No need to syntax-highlight.
• Whitespace agnostic.
• Fully internationalized. Most programming languages are biased towards English speakers. Not HeartForth!

Disadvantages

• None.

Why would you do this?

My friend Ian Baker wondered whether anyone had yet made an all-Emoji programming language. My first thought was to do a Lisp, but I was disappointed in how much the parentheses dominated the visual look. What we needed was a language which was more stream-of-consciousness, like the way people use Emoji already.

A long time ago I had used another stack-based language, PostScript. They have this curious property of being streams of keywords with some data mixed in. Just like a block of Emoji. Once I realized I could match hearts to stack operators I knew I was onto something. I originally tried implementing a new stack language in pure JavaScript, which was surprisingly easy to get started but surprisingly hard to do things like recursion well. So I decided to simply source-translate to an existing Forth implementation instead.

Complete glossary

HeartForth	Standard Forth	meaning
	dup	( a -> a a )
	drop	( a -> )
	over	( a b -> a b a )
	rot	( a b c -> b c a )
	swap	( a b -> b a )
	.	show last item on stack
	dump	show entire stack
	+	add
	-	subtract
	*	multiply
	/	divide
	=	equals
	>	greater than
	<	less than
	:	begin function definition
	;	end function definition
	?do	do block if > 0
	loop	loop
	begin	start block
	until	end loop condition
	if	if
	then	then

Thanks to

Aadit M. Shah posted this answer on Stack Exchange, which helped me get started.

The repl.it project and ForthFreak for bringing Forth to JavaScript.

Dedication

For my lovely girlfriend Melanie. I heart you 100 factorial .