[Openmcl-devel] multiple read-time conditionals, puzzlement

[Robert Munyer]

On 13 March 2023, Arthur Cater wrote:

> '(#+a #-b #+c a b c)

Yikes!

Sometimes, when I have a line of code whose internal structure isn't obvious,
I break it into multiple lines so indentation can elucidate the structure.

If I were to try to do that with this small but monstrous[*] line of code,
I would have to indent it four different ways simultaneously!

If features B and C are present, the internal structure is:

    '(#+a #-b #+c a
          b
      c)

If B and C are absent:

    '(#+a #-b #+c a
              b
      c)

If B is present but C is absent:

    '(#+a #-b #+c a
              b
          c)

If B is absent but C is present:

    '(#+a #-b #+c a
      b
      c)

[*] I suppose that Forth experts probably would not consider
this kind of construct to be monstrous.  I am not a Forth expert.