1*b8851fccSafresh1use strict; 2*b8851fccSafresh1use warnings; 3*b8851fccSafresh1 4*b8851fccSafresh1# A tiny private library routine which is a helper to several Perl core 5*b8851fccSafresh1# modules, to allow a paradigm to be implemented in a single place. The name, 6*b8851fccSafresh1# contents, or even the existence of this file may be changed at any time and 7*b8851fccSafresh1# are NOT to be used by anything outside the Perl core. 8*b8851fccSafresh1 9*b8851fccSafresh1sub _meta_notation ($) { 10*b8851fccSafresh1 11*b8851fccSafresh1 # Returns a copy of the input string with the nonprintable characters 12*b8851fccSafresh1 # below 0x100 changed into printables. Any ASCII printables or above 0xFF 13*b8851fccSafresh1 # are unchanged. (XXX Probably above-Latin1 characters should be 14*b8851fccSafresh1 # converted to \X{...}) 15*b8851fccSafresh1 # 16*b8851fccSafresh1 # \0 .. \x1F (which are "\c@" .. "\c_") are changed into ^@, ^A, ^B, ... 17*b8851fccSafresh1 # ^Z, ^[, ^\, ^], ^^, ^_ 18*b8851fccSafresh1 # \c? is changed into ^?. 19*b8851fccSafresh1 # 20*b8851fccSafresh1 # The above accounts for all the ASCII-range nonprintables. 21*b8851fccSafresh1 # 22*b8851fccSafresh1 # On ASCII platforms, the upper-Latin1-range characters are converted to 23*b8851fccSafresh1 # Meta notation, so that \xC1 becomes 'M-A', \xE2 becomes 'M-b', etc. 24*b8851fccSafresh1 # This is how it always has worked, so is continued that way for backwards 25*b8851fccSafresh1 # compatibility. The range \x80 .. \x9F becomes M-^@ .. M-^A, M-^B, ... 26*b8851fccSafresh1 # M-^Z, M-^[, M-^\, M-^], M-^, M-^_ 27*b8851fccSafresh1 # 28*b8851fccSafresh1 # On EBCDIC platforms, the upper-Latin1-range characters are converted 29*b8851fccSafresh1 # into '\x{...}' Meta notation doesn't make sense on EBCDIC platforms 30*b8851fccSafresh1 # because the ASCII-range printables are a mixture of upper bit set or 31*b8851fccSafresh1 # not. [A-Za-Z0-9] all have the upper bit set. The underscore likely 32*b8851fccSafresh1 # doesn't; and other punctuation may or may not. There's no simple 33*b8851fccSafresh1 # pattern. 34*b8851fccSafresh1 35*b8851fccSafresh1 my $string = shift; 36*b8851fccSafresh1 37*b8851fccSafresh1 $string =~ s/([\0-\037])/ 38*b8851fccSafresh1 sprintf("^%c",utf8::unicode_to_native(ord($1)^64))/xeg; 39*b8851fccSafresh1 $string =~ s/\c?/^?/g; 40*b8851fccSafresh1 if (ord("A") == 65) { 41*b8851fccSafresh1 $string =~ s/([\200-\237])/sprintf("M-^%c",(ord($1)&0177)^64)/eg; 42*b8851fccSafresh1 $string =~ s/([\240-\377])/sprintf("M-%c" ,ord($1)&0177)/eg; 43*b8851fccSafresh1 } 44*b8851fccSafresh1 else { 45*b8851fccSafresh1 # Leave alone things above \xff 46*b8851fccSafresh1 $string =~ s/( (?[ [\x00-\xFF] & [:^print:]])) / 47*b8851fccSafresh1 sprintf("\\x{%X}", ord($1))/xaeg; 48*b8851fccSafresh1 } 49*b8851fccSafresh1 50*b8851fccSafresh1 return $string; 51*b8851fccSafresh1} 52*b8851fccSafresh11 53