[racket] question about naming convention

From: Danny Heap (heap at cs.toronto.edu)
Date: Sat May 19 11:01:57 EDT 2012

(re-sent after joining mailing list)

On Sat, May 19, 2012 at 10:46:11AM -0400, Danny Heap wrote:

I wrote a small module for the convenience of my students in
manipulating image color-lists in 2htdp/image.  I want them
to be able to create a new color one band at a time, and in my draft I
have, for instance:

; new-red : number color -> color
; Produces a new color by replacing
; the red intensity of col by val.
(define (new-red val col) ...)

Is there a convention for naming, rather than new-???, that makes it
obvious that there is no mutation going on?  I'm not fond of the
de-banged set-??? since that raises the (absent) mutation question.
So, I don't think I want set-red, for example.  Some suggestions I'm
considering other than new-red:

(with-red val col)
(update-with-red val col)
(replace-red val col)

Each of these has an unfortunate connation of mutation for me, but if
there's an established convention, I'll use (and teach) that.

I also included an image comprehension, for/image, to suppress the
details of image->color-list, followed by color-list->bitmap, in
transforming an image.  I read some of the discussion on preferring
map over the for- comprehensions, but I want to allow my students to
transform colors at the expression level, without the overhead of
functions, named or anonymous.  Are there grievous pedagogical
implications I should be aware of?

Danny Heap
BA4270			416-978-5899
heap at cs.utoronto.ca	http://www.cs.utoronto.ca/~heap

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