[Networkagent-developers] expand, front, ifdef

[Theodore H. <tw...@do...>]

A few more items on the wish list:

1. expand() would be more useful if it returned empty strings between
token delimiters; that is, expand("twh1:*::::/homes/twh1:/bin/tcsh", ":")
would be ["twh1", "*", "", "", "", "/homes/twh1", "/bin/tcsh"] and
expand("/var/tmp", "/") would be ["", "var", "tmp"].

This has a number of advantages:
- you could use it to parse delimited records like those in /etc/passwd
  (currently you can't detect blank fields), or to distinguish relative
  and absolute paths
- you can use expand(s,"") to iterate over characters, instead of doing
  a bunch of ascii's and charof's (which I end up doing a lot)
- we would have the identity: collapse(expand(s,c),c) == s
  (if c contains one character)
- if you need the old behavior, you can always simulate it with:
      expand(s,d) reject ""


2. It would be convenient if front(L,N) returned [] when N < 0, analogously
to tail(L,N) when N > listlen(L).  For example, front(L,listlen(L)-1) could
be used to unconditionally drop the last element from a list if it exists.
Similarly, tail(L,N) could return L when N < 0.

This would give rise to the identity:
tail(L,N) == reverse(front((reverse(L), listlen(L)-N)) and
front(L,N) == reverse(tail((reverse(L), listlen(L)-N)).


3. It would be really helpful to have some means of commenting out a large
block of code, like #ifdef DEBUG ... #endif.

theo