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4b6af431 KW |
1 | use strict; |
2 | use warnings; | |
3 | ||
4 | # A tiny private library routine which is a helper to several Perl core | |
5 | # modules, to allow a paradigm to be implemented in a single place. The name, | |
6 | # contents, or even the existence of this file may be changed at any time and | |
6908751b | 7 | # are NOT to be used by anything outside the Perl core. |
4b6af431 KW |
8 | |
9 | sub _meta_notation ($) { | |
10 | ||
11 | # Returns a copy of the input string with the nonprintable characters | |
12 | # below 0x100 changed into printables. Any ASCII printables or above 0xFF | |
13 | # are unchanged. (XXX Probably above-Latin1 characters should be | |
14 | # converted to \X{...}) | |
15 | # | |
16 | # \0 .. \x1F (which are "\c@" .. "\c_") are changed into ^@, ^A, ^B, ... | |
17 | # ^Z, ^[, ^\, ^], ^^, ^_ | |
18 | # \c? is changed into ^?. | |
19 | # | |
20 | # The above accounts for all the ASCII-range nonprintables. | |
21 | # | |
22 | # On ASCII platforms, the upper-Latin1-range characters are converted to | |
23 | # Meta notation, so that \xC1 becomes 'M-A', \xE2 becomes 'M-b', etc. | |
24 | # This is how it always has worked, so is continued that way for backwards | |
273b29a4 KW |
25 | # compatibility. The range \x80 .. \x9F becomes M-^@ .. M-^A, M-^B, ... |
26 | # M-^Z, M-^[, M-^\, M-^], M-^, M-^_ | |
4b6af431 KW |
27 | # |
28 | # On EBCDIC platforms, the upper-Latin1-range characters are converted | |
29 | # into '\x{...}' Meta notation doesn't make sense on EBCDIC platforms | |
30 | # because the ASCII-range printables are a mixture of upper bit set or | |
31 | # not. [A-Za-Z0-9] all have the upper bit set. The underscore likely | |
32 | # doesn't; and other punctuation may or may not. There's no simple | |
33 | # pattern. | |
34 | ||
35 | my $string = shift; | |
36 | ||
37 | $string =~ s/([\0-\037])/ | |
38 | sprintf("^%c",utf8::unicode_to_native(ord($1)^64))/xeg; | |
39 | $string =~ s/\c?/^?/g; | |
40 | if (ord("A") == 65) { | |
273b29a4 KW |
41 | $string =~ s/([\200-\237])/sprintf("M-^%c",(ord($1)&0177)^64)/eg; |
42 | $string =~ s/([\240-\377])/sprintf("M-%c" ,ord($1)&0177)/eg; | |
4b6af431 KW |
43 | } |
44 | else { | |
45 | no warnings 'experimental::regex_sets'; | |
46 | # Leave alone things above \xff | |
47 | $string =~ s/( (?[ [\x00-\xFF] & [:^print:]])) / | |
48 | sprintf("\\x{%X}", ord($1))/xaeg; | |
49 | } | |
50 | ||
51 | return $string; | |
52 | } | |
53 | 1 |