procedure slashbal: bal() with escapes procedure slashupto: upto() with escapes procedure slshupto: upto() with escapes procedure snapshot: snapshot of string scanning procedure balq: bal() with quote escaping. procedure balqc: balq() with comment escaping procedure limatch: matching items in list
link scan
May 2, 2001; Richard L. Goerwitz, David A. Gamey, and Ralph E. Griswold
Contributors: Randal L. Schwartz and Cheyenne Wills
This file is in the public domain.
This module contains procedures related to string scanning:
balq(c1, c2, c3, c4, c5, s, i1, i2)
like bal() with quoting from characters in c5.
balqc(c1, c2, c3, c4, c5, s1, s2, s3, i1, i2)
like balq() with the addition that balanced characters within
"comments", as delimited by the strings s1 and s2, are also
excluded from balancing. In addition, if s1 is given and s2
limatch(L, c)
matches items in list L delimited by characters in c
slashbal(c1, c2, c3, s, i, j)
like bal() with escape processing
slashupto(c, s, i, j)
like upto() with escape processing
slshupto()
synonym for slashupto()
snapshot(title, len)
snapshot of string scanning with optional title and
maximum length.
More extensive documentation proceeds each procedure.
____________________________________________________________
Richard L. Goerwitz:
I am often frustrated at bal()'s inability to deal elegantly with
the common \backslash escaping convention (a way of telling Unix
Bourne and C shells, for instance, not to interpret a given
character as a "metacharacter"). I recognize that bal()'s generic
behavior is a must, and so I wrote slashbal() to fill the gap.
Slashbal behaves like bal, except that it ignores, for purposes of
balancing, any c2/c3 char which is preceded by a backslash. Note
that we are talking about internally represented backslashes, and
not necessarily the backslashes used in Icon string literals. If
you have "\(" in your source code, the string produced will have no
backslash. To get this effect, you would need to write "\\(."
BUGS: Note that, like bal() (v8), slashbal() cannot correctly
handle cases where c2 and c3 intersect. Note also that older ver-
sions of this routine counted from the beginning of the string,
instead of from i. This feature came to be regarded as a bug when
put into actual use (especially when I realized that bal() doesn't
work this way).