X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlop.pod;h=3c84e608019577152a60d6e74ec8237770c16025;hb=40b568c93a31cb8feae8a14551365dff7e76b624;hp=db0563ce91e9781abdd8af3364d19d5f074da336;hpb=4a4eefd0ee0da7b6a2b5b0d021684bca80971b79;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlop.pod b/pod/perlop.pod index db0563c..3c84e60 100644 --- a/pod/perlop.pod +++ b/pod/perlop.pod @@ -788,8 +788,8 @@ If "'" is the delimiter, no interpolation is performed on the PATTERN. PATTERN may contain variables, which will be interpolated (and the pattern recompiled) every time the pattern search is evaluated, except -for when the delimiter is a single quote. (Note that C<$)> and C<$|> -might not be interpolated because they look like end-of-string tests.) +for when the delimiter is a single quote. (Note that C<$(>, C<$)>, and +C<$|> are not interpolated because they look like end-of-string tests.) If you want such a pattern to be compiled only once, add a C after the trailing delimiter. This avoids expensive run-time recompilations, and is useful when the value you are interpolating won't change over @@ -1140,9 +1140,10 @@ text is not evaluated as a command. If the PATTERN is delimited by bracketing quotes, the REPLACEMENT has its own pair of quotes, which may or may not be bracketing quotes, e.g., C or C<< s/bar/ >>. A C will cause the -replacement portion to be interpreted as a full-fledged Perl expression -and eval()ed right then and there. It is, however, syntax checked at -compile-time. +replacement portion to be treated as a full-fledged Perl expression +and evaluated right then and there. It is, however, syntax checked at +compile-time. A second C modifier will cause the replacement portion +to be Ced before being run as a Perl expression. Examples: @@ -1169,8 +1170,12 @@ Examples: # symbolic dereferencing s/\$(\w+)/${$1}/g; - # /e's can even nest; this will expand - # any embedded scalar variable (including lexicals) in $_ + # Add one to the value of any numbers in the string + s/(\d+)/1 + $1/eg; + + # This will expand any embedded scalar variable + # (including lexicals) in $_ : First $1 is interpolated + # to the variable name, and then evaluated s/(\$\w+)/$1/eeg; # Delete (most) C comments. @@ -1202,9 +1207,9 @@ to occur that you might want. Here are two common cases: # expand tabs to 8-column spacing 1 while s/\t+/' ' x (length($&)*8 - length($`)%8)/e; -=item tr/SEARCHLIST/REPLACEMENTLIST/cdsUC +=item tr/SEARCHLIST/REPLACEMENTLIST/cds -=item y/SEARCHLIST/REPLACEMENTLIST/cdsUC +=item y/SEARCHLIST/REPLACEMENTLIST/cds Transliterates all occurrences of the characters found in the search list with the corresponding character in the replacement list. It returns @@ -1220,6 +1225,12 @@ SEARCHLIST is delimited by bracketing quotes, the REPLACEMENTLIST has its own pair of quotes, which may or may not be bracketing quotes, e.g., C or C. +Note that C does B do regular expression character classes +such as C<\d> or C<[:lower:]>. The operator is not equivalent to +the tr(1) utility. If you want to map strings between lower/upper +cases, see L and L, and in general consider +using the C operator if you need regular expressions. + Note also that the whole range idea is rather unportable between character sets--and even within character sets they may cause results you probably didn't expect. A sound principle is to use only ranges @@ -1232,8 +1243,6 @@ Options: c Complement the SEARCHLIST. d Delete found but unreplaced characters. s Squash duplicate replaced characters. - U Translate to/from UTF-8. - C Translate to/from 8-bit char (octet). If the C modifier is specified, the SEARCHLIST character set is complemented. If the C modifier is specified, any characters @@ -1251,10 +1260,6 @@ enough. If the REPLACEMENTLIST is empty, the SEARCHLIST is replicated. This latter is useful for counting characters in a class or for squashing character sequences in a class. -The first C or C modifier applies to the left side of the translation. -The second one applies to the right side. If present, these modifiers override -the current utf8 state. - Examples: $ARGV[1] =~ tr/A-Z/a-z/; # canonicalize to lower case @@ -1274,9 +1279,6 @@ Examples: tr [\200-\377] [\000-\177]; # delete 8th bit - tr/\0-\xFF//CU; # change Latin-1 to Unicode - tr/\0-\x{FF}//UC; # change Unicode to Latin-1 - If multiple transliterations are given for a character, only the first one is used: @@ -1407,7 +1409,7 @@ as C<"\\\t"> (since TAB is not alphanumeric). Note also that: may be closer to the conjectural I of the writer of C<"\Q\t\E">. Interpolated scalars and arrays are converted internally to the C and -C<.> catentation operations. Thus, C<"$foo XXX '@arr'"> becomes: +C<.> catenation operations. Thus, C<"$foo XXX '@arr'"> becomes: $foo . " XXX '" . (join $", @arr) . "'"; @@ -1726,7 +1728,7 @@ A (file)glob evaluates its (embedded) argument only when it is starting a new list. All values must be read before it will start over. In list context, this isn't important because you automatically get them all anyway. However, in scalar context the operator returns -the next value each time it's called, or C +the next value each time it's called, or C when the list has run out. As with filehandle reads, an automatic C is generated when the glob occurs in the test part of a C, because legal glob returns (e.g. a file called F<0>) would otherwise