NAME¶
ExtUtils::XSSymSet - keep sets of symbol names palatable to the VMS linker
SYNOPSIS¶
use ExtUtils::XSSymSet;
$set = new ExtUtils::XSSymSet;
while ($sym = make_symbol()) { $set->addsym($sym); }
foreach $safesym ($set->all_trimmed) {
print "Processing $safesym (derived from ",
$self->get_orig($safesym), ")\n";
do_stuff($safesym);
}
$safesym = ExtUtils::XSSymSet->trimsym($onesym);
DESCRIPTION¶
Since the VMS linker distinguishes symbols based only on the first 31 characters
of their names, it is occasionally necessary to shorten symbol names in order
to avoid collisions. (This is especially true of names generated by xsubpp,
since prefixes generated by nested package names can become quite long.)
"ExtUtils::XSSymSet" provides functions to shorten names in a
consistent fashion, and to track a set of names to insure that each is unique.
While designed with
xsubpp in mind, it may be used with any set of
strings.
This package supplies the following functions, all of which should be called as
methods.
- new([$maxlen[,$silent]])
- Creates an empty "ExtUtils::XSSymset" set of symbols. This
function may be called as a static method or via an existing object. If
$maxlen or $silent are specified, they are used as the defaults for
maximum name length and warning behavior in future calls to
addsym() or trimsym() via this object. If the compiler has
been instructed to do its own symbol shortening via
$Config{'useshortenedsymbols'}, a value of 2048 is assumed for $maxlen as
a way of bypassing the shortening done by this module.
- addsym($name[,$maxlen[,$silent]])
- Creates a symbol name from $name, using the methods described under
trimsym(), which is unique in this set of symbols, and returns the
new name. $name and its resultant are added to the set, and any future
calls to addsym() specifying the same $name will return the same
result, regardless of the value of $maxlen specified. Unless $silent is
true, warnings are output if $name had to be trimmed or changed in order
to avoid collision with an existing symbol name. $maxlen and $silent
default to the values specified when this set of symbols was created. This
method must be called via an existing object.
- trimsym($name[,$maxlen[,$silent]])
- Creates a symbol name $maxlen or fewer characters long from $name and
returns it. If $name is too long, it first tries to shorten it by removing
duplicate characters, then by periodically removing non-underscore
characters, and finally, if necessary, by periodically removing characters
of any type. $maxlen defaults to 31. Unless $silent is true, a warning is
output if $name is altered in any way. This function may be called either
as a static method or via an existing object, but in the latter case no
check is made to insure that the resulting name is unique in the set of
symbols. If the compiler has been instructed to do its own symbol
shortening via $Config{'useshortenedsymbols'}, a value of 2048 is assumed
for $maxlen as a way of bypassing the shortening done by this module.
- delsym($name)
- Removes $name from the set of symbols, where $name is the original symbol
name passed previously to addsym(). If $name existed in the set of
symbols, returns its "trimmed" equivalent, otherwise returns
"undef". This method must be called via an existing object.
- get_orig($trimmed)
- Returns the original name which was trimmed to $trimmed by a previous call
to addsym(), or "undef" if $trimmed does not correspond
to a member of this set of symbols. This method must be called via an
existing object.
- get_trimmed($name)
- Returns the trimmed name which was generated from $name by a previous call
to addsym(), or "undef" if $name is not a member of this
set of symbols. This method must be called via an existing object.
- all_orig()
- Returns a list containing all of the original symbol names from this
set.
- all_trimmed()
- Returns a list containing all of the trimmed symbol names from this
set.
AUTHOR¶
Charles Bailey <
bailey@newman.upenn.edu>
REVISION¶
Last revised 8-Oct-2010, for Perl 5.13.6.