LTR stack on left?

[cben]

https://www.youtube.com/watch?v=EkzoevQ19Pk shows a very nice layout for visualizing stack-based language execution, also similar to http://www.nsl.com/k/xy/xy.htm model (and probably has been re-invented many times):

stack	current-word	continuation
		3 square 4 square +
	3	square
3		dup * · 4 square +
3	dup	* · 4 square +
3 3	*	· 4 square +
9	4	square +
9 4	square	+
9 4		dup * · +
9 16	+
25

• the whole program starts on the right
• taking a step takes first word from continuation and executes it
• that usually does something to right edge of stack, e.g. numbers just shift left :-)
• a definition can be "exploded" back into the continuation
  • its end is marked with a no-op · which supports "jump over" to complete function execution, instead of default single-stepping.

---

However, I want to keep text editable, don't want it to actaully disapper.

But things I can do to approach this:

• move stack to left of editor
• orient stack left-to-right
• dim "consumed" words from start to cursor.

Hmm, the program is not necessarily horizontal 🤔 It can consist of many lines.
(Current vertical stack layout inspired by terminal REPL where each word was typed on separate line and stack was printed vertically between words:

black
    [█]
white
    [█]
    [ ]
fade
    [█▓▒░ ]

[cben]

Fascinating: spatial metaphors for time vary by culture!
See Remembrances of times East, and related research e.g. The future is in front, to the right, or below: Development of spatial representations of time in three dimensions , etc.

We tested children in India because the prevalence of both horizontal and vertical calendars there provided a unique opportunity to investigate how calendar orientation and writing direction might each influence the development of the horizontal/vertical mental timeline.