1ExtUtils::XSSymSet(3pm)Perl Programmers Reference GuideExtUtils::XSSymSet(3pm)
2
6 ExtUtils::XSSymSet - keep sets of symbol names palatable to the VMS
7 linker
8
10 use ExtUtils::XSSymSet;
11 $set = new ExtUtils::XSSymSet;
13 while ($sym = make_symbol()) { $set->addsym($sym); }
14 foreach $safesym ($set->all_trimmed) {
15 print "Processing $safesym (derived from ",$self->get_orig($safesym),")\n";
16 do_stuff($safesym);
17 }
18 $safesym = ExtUtils::XSSymSet->trimsym($onesym);
20
22 Since the VMS linker distinguishes symbols based only on the first 31
23 characters of their names, it is occasionally necessary to shorten
24 symbol names in order to avoid collisions. (This is especially true of
25 names generated by xsubpp, since prefixes generated by nested package
26 names can become quite long.) "ExtUtils::XSSymSet" provides functions
27 to shorten names in a consistent fashion, and to track a set of names
28 to insure that each is unique. While designed with xsubpp in mind, it
29 may be used with any set of strings.
30 This package supplies the following functions, all of which should be
32 called as methods.
33 new([$maxlen[,$silent]])
35 Creates an empty "ExtUtils::XSSymset" set of symbols. This
36 function may be called as a static method or via an existing
37 object. If $maxlen or $silent are specified, they are used as the
38 defaults for maximum name length and warning behavior in future
39 calls to addsym() or trimsym() via this object. If the compiler
40 has been instructed to do its own symbol shortening via
41 $Config{'useshortenedsymbols'}, a value of 2048 is assumed for
42 $maxlen as a way of bypassing the shortening done by this module.
43 addsym($name[,$maxlen[,$silent]])
45 Creates a symbol name from $name, using the methods described under
46 trimsym(), which is unique in this set of symbols, and returns the
47 new name. $name and its resultant are added to the set, and any
48 future calls to addsym() specifying the same $name will return the
49 same result, regardless of the value of $maxlen specified. Unless
50 $silent is true, warnings are output if $name had to be trimmed or
51 changed in order to avoid collision with an existing symbol name.
52 $maxlen and $silent default to the values specified when this set
53 of symbols was created. This method must be called via an existing
54 object.
55 trimsym($name[,$maxlen[,$silent]])
57 Creates a symbol name $maxlen or fewer characters long from $name
58 and returns it. If $name is too long, it first tries to shorten it
59 by removing duplicate characters, then by periodically removing
60 non-underscore characters, and finally, if necessary, by
61 periodically removing characters of any type. $maxlen defaults to
62 31. Unless $silent is true, a warning is output if $name is
63 altered in any way. This function may be called either as a static
64 method or via an existing object, but in the latter case no check
65 is made to insure that the resulting name is unique in the set of
66 symbols. If the compiler has been instructed to do its own
67 symbol shortening via $Config{'useshortenedsymbols'}, a value of
68 2048 is assumed for $maxlen as a way of bypassing the shortening
69 done by this module.
70 delsym($name)
72 Removes $name from the set of symbols, where $name is the original
73 symbol name passed previously to addsym(). If $name existed in the
74 set of symbols, returns its "trimmed" equivalent, otherwise returns
75 "undef". This method must be called via an existing object.
76 get_orig($trimmed)
78 Returns the original name which was trimmed to $trimmed by a
79 previous call to addsym(), or "undef" if $trimmed does not
80 correspond to a member of this set of symbols. This method must be
81 called via an existing object.
82 get_trimmed($name)
84 Returns the trimmed name which was generated from $name by a
85 previous call to addsym(), or "undef" if $name is not a member of
86 this set of symbols. This method must be called via an existing
87 object.
88 all_orig()
90 Returns a list containing all of the original symbol names from
91 this set.
92 all_trimmed()
94 Returns a list containing all of the trimmed symbol names from this
95 set.
96
98 Charles Bailey <bailey@newman.upenn.edu>
99
101 Last revised 8-Oct-2010, for Perl 5.13.6.
102perl v5.16.3 2013-03-04 ExtUtils::XSSymSet(3pm)