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Member "install-tl-20200916/tlpkg/tlperl/lib/meta_notation.pm" (18 Apr 2017, 2117 Bytes) of package /windows/misc/install-tl.zip:


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    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
    7 # are NOT to be used by anything outside the Perl core.
    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
   25     # compatibility.  The range \x80 .. \x9F becomes M-^@ .. M-^A, M-^B, ...
   26     # M-^Z, M-^[, M-^\, M-^], M-^, M-^_
   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) {
   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;
   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