Bison has been using for years a trick with argmatch: exploit
the support for partial matches to have a simple documentation
system:
$ bison --trace=help
bison: invalid argument ‘help’ for ‘--trace’
Valid arguments are:
- ‘none - no traces’
- ‘scan - grammar scanner traces’
- ‘parse - grammar parser traces’
- ‘parse-stats - grammar parser stats’
- ‘automaton - construction of the automaton’
- ‘bitsets - use of bitsets’
- ‘closure - input/output of closure’
- ‘grammar - reading, reducing the grammar’
- ‘resource - memory consumption (where available)’
- ‘sets - grammar sets: firsts, nullable etc.’
- ‘muscles - m4 definitions passed to the skeleton’
- ‘tools - m4 invocation’
- ‘m4 - m4 traces’
- ‘skeleton - skeleton postprocessing’
- ‘time - time consumption’
- ‘ielr - IELR conversion’
- ‘all - all of the above’
This is a low profile feature, meant for Bison developers and
contributors, not end users, so i18n is not an issue here.
However, I just introduced the parse-stats category, and as a
consequence "--trace=parse" no longer matches the corresponding
item, since "parse" is a prefix for both
"parse - grammar parser traces" and
"parse-stats - grammar parser stats".
I don't think people are using arguments with spaces, so I propose
to acknowledge this use of argmatch by accepting as a perfect match
the first option, since "parse" is a prefix followed by a space.
WDYT?
commit 7fc1d6af473b6572bc643e0481ac0e04f9150cd1
Author: Akim Demaille <akim.demai...@gmail.com>
Date: Thu Apr 18 22:48:29 2019 +0200
argmatch: accept perfect matches in documented arglists
* lib/argmatch.c (argmatch): Consider effective arguments that are
prefix of one of the arglist followed by a space to be perfect
matches.
diff --git a/ChangeLog b/ChangeLog
index 7d6cb0b0a..0ce1de17d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2019-04-18 Akim Demaille <a...@lrde.epita.fr>
+
+ argmatch: accept perfect matches in documented arglists.
+ * lib/argmatch.c (argmatch): Consider effective arguments that are
+ prefix of one of the arglist followed by a space to be perfect
+ matches.
+
2019-04-18 Akim Demaille <a...@lrde.epita.fr>
argmatch: use void* for raw memory pointers
diff --git a/lib/argmatch.c b/lib/argmatch.c
index 7666ef414..79512125c 100644
--- a/lib/argmatch.c
+++ b/lib/argmatch.c
@@ -78,7 +78,17 @@ argmatch_exit_fn argmatch_die = __argmatch_die;
synonyms, i.e., for
"yes", "yop" -> 0
"no", "nope" -> 1
- "y" is a valid argument, for 0, and "n" for 1. */
+ "y" is a valid argument, for 0, and "n" for 1.
+
+ Accept arguments with a documentation string, such as:
+ "foo - a first feature" -> 0
+ "bar - a second feature" -> 1
+ "barest - a better second feature" -> 2
+ In this case, "ba" is ambiguous, but accept "bar" as a perfect
+ match of 1, even though technically it is also a prefix for 2.
+ This is because "bar" is followed by a space in the argument list
+ ("bar - a second feature").
+ */
ptrdiff_t
argmatch (const char *arg, const char *const *arglist,
@@ -96,7 +106,8 @@ argmatch (const char *arg, const char *const *arglist,
{
if (!strncmp (arglist[i], arg, arglen))
{
- if (strlen (arglist[i]) == arglen)
+ if (strlen (arglist[i]) == arglen
+ || (arglen < strlen (arglist[i]) && arglist[i][arglen] == ' '))
/* Exact match found. */
return i;
else if (matchind == -1)
