Re: Sequence functions

[Scott.Fahlman at CMU-10A]

Guy,

I agree that the index-range and the comparison-choice parameters are
orthogonal.  I like your proposal to use SUBSEQ for the ranges -- it
would appear to be no harder to optimize this in the compiler than to
do the equivalent keyword or optional argument thing, and the added
consing in interpreted code (only!)  should not make much difference.
And the semantics of what is going on with all the start and end
options now becomes crystal clear.  We would need a style suggestion in
the manual urging the programmer to use SUBSEQ for this and not some
random thing he cooks up, since the compiler will only recognize fairly
obvious cases.  Good idea!

I do not like the part of your proposal that relates to reordering the
arguments, on the grounds of gross incompatibility.  Unless we want to
come up with totally new names for all these functions, the change will
make it a real pain to move code and programmers over from Maclisp or
Franz.  Too high a price to pay for epsilon increase in elegance.  I
guess that of the suggestions I've seen so far, I would go with your
subseq idea for ranges and my keywords for specifying the comparison,
throwing out the IF family.

-- Scott