source: trunk/essentials/dev-lang/perl/lib/English.pm@ 3310

package English;

our $VERSION = '1.02';

require Exporter;
@ISA = (Exporter);

=head1 NAME

English - use nice English (or awk) names for ugly punctuation variables

=head1 SYNOPSIS

    use English qw( -no_match_vars ) ;  # Avoids regex performance penalty
    use English;
    ...
    if ($ERRNO =~ /denied/) { ... }

=head1 DESCRIPTION

This module provides aliases for the built-in variables whose
names no one seems to like to read.  Variables with side-effects
which get triggered just by accessing them (like $0) will still 
be affected.

For those variables that have an B<awk> version, both long
and short English alternatives are provided.  For example, 
the C<$/> variable can be referred to either $RS or 
$INPUT_RECORD_SEPARATOR if you are using the English module.

See L<perlvar> for a complete list of these.

=head1 PERFORMANCE

This module can provoke sizeable inefficiencies for regular expressions,
due to unfortunate implementation details.  If performance matters in
your application and you don't need $PREMATCH, $MATCH, or $POSTMATCH,
try doing

   use English qw( -no_match_vars ) ;

.  B<It is especially important to do this in modules to avoid penalizing
all applications which use them.>

=cut

no warnings;

my $globbed_match ;

# Grandfather $NAME import
sub import {
    my $this = shift;
    my @list = grep { ! /^-no_match_vars$/ } @_ ;
    local $Exporter::ExportLevel = 1;
    if ( @_ == @list ) {
        *EXPORT = \@COMPLETE_EXPORT ;
        $globbed_match ||= (
            eval q{
                *MATCH                          = *&    ;
                *PREMATCH                       = *`    ;
                *POSTMATCH                      = *'    ;
                1 ;
               }
            || do {
                require Carp ;
                Carp::croak "Can't create English for match leftovers: $@" ;
            }
        ) ;
    }
    else {
        *EXPORT = \@MINIMAL_EXPORT ;
    }
    Exporter::import($this,grep {s/^\$/*/} @list);
}

@MINIMAL_EXPORT = qw(
        *ARG
        *LAST_PAREN_MATCH
        *INPUT_LINE_NUMBER
        *NR
        *INPUT_RECORD_SEPARATOR
        *RS
        *OUTPUT_AUTOFLUSH
        *OUTPUT_FIELD_SEPARATOR
        *OFS
        *OUTPUT_RECORD_SEPARATOR
        *ORS
        *LIST_SEPARATOR
        *SUBSCRIPT_SEPARATOR
        *SUBSEP
        *FORMAT_PAGE_NUMBER
        *FORMAT_LINES_PER_PAGE
        *FORMAT_LINES_LEFT
        *FORMAT_NAME
        *FORMAT_TOP_NAME
        *FORMAT_LINE_BREAK_CHARACTERS
        *FORMAT_FORMFEED
        *CHILD_ERROR
        *OS_ERROR
        *ERRNO
        *EXTENDED_OS_ERROR
        *EVAL_ERROR
        *PROCESS_ID
        *PID
        *REAL_USER_ID
        *UID
        *EFFECTIVE_USER_ID
        *EUID
        *REAL_GROUP_ID
        *GID
        *EFFECTIVE_GROUP_ID
        *EGID
        *PROGRAM_NAME
        *PERL_VERSION
        *ACCUMULATOR
        *COMPILING
        *DEBUGGING
        *SYSTEM_FD_MAX
        *INPLACE_EDIT
        *PERLDB
        *BASETIME
        *WARNING
        *EXECUTABLE_NAME
        *OSNAME
        *LAST_REGEXP_CODE_RESULT
        *EXCEPTIONS_BEING_CAUGHT
        *LAST_SUBMATCH_RESULT
        @LAST_MATCH_START
        @LAST_MATCH_END
);


@MATCH_EXPORT = qw(
        *MATCH
        *PREMATCH
        *POSTMATCH
);

@COMPLETE_EXPORT = ( @MINIMAL_EXPORT, @MATCH_EXPORT ) ;

# The ground of all being. @ARG is deprecated (5.005 makes @_ lexical)

        *ARG                                    = *_    ;

# Matching.

        *LAST_PAREN_MATCH                       = *+    ;
        *LAST_SUBMATCH_RESULT                   = *^N ;
        *LAST_MATCH_START                       = *-{ARRAY} ;
        *LAST_MATCH_END                         = *+{ARRAY} ;

# Input.

        *INPUT_LINE_NUMBER                      = *.    ;
            *NR                                 = *.    ;
        *INPUT_RECORD_SEPARATOR                 = */    ;
            *RS                                 = */    ;

# Output.

        *OUTPUT_AUTOFLUSH                       = *|    ;
        *OUTPUT_FIELD_SEPARATOR                 = *,    ;
            *OFS                                = *,    ;
        *OUTPUT_RECORD_SEPARATOR                = *\    ;
            *ORS                                = *\    ;

# Interpolation "constants".

        *LIST_SEPARATOR                         = *"    ;
        *SUBSCRIPT_SEPARATOR                    = *;    ;
            *SUBSEP                             = *;    ;

# Formats

        *FORMAT_PAGE_NUMBER                     = *%    ;
        *FORMAT_LINES_PER_PAGE                  = *=    ;
        *FORMAT_LINES_LEFT                      = *-    ;
        *FORMAT_NAME                            = *~    ;
        *FORMAT_TOP_NAME                        = *^    ;
        *FORMAT_LINE_BREAK_CHARACTERS           = *:    ;
        *FORMAT_FORMFEED                        = *^L   ;

# Error status.

        *CHILD_ERROR                            = *?    ;
        *OS_ERROR                               = *!    ;
            *ERRNO                              = *!    ;
        *OS_ERROR                               = *!    ;
            *ERRNO                              = *!    ;
        *EXTENDED_OS_ERROR                      = *^E   ;
        *EVAL_ERROR                             = *@    ;

# Process info.

        *PROCESS_ID                             = *$    ;
            *PID                                = *$    ;
        *REAL_USER_ID                           = *<    ;
            *UID                                = *<    ;
        *EFFECTIVE_USER_ID                      = *>    ;
            *EUID                               = *>    ;
        *REAL_GROUP_ID                          = *(    ;
            *GID                                = *(    ;
        *EFFECTIVE_GROUP_ID                     = *)    ;
            *EGID                               = *)    ;
        *PROGRAM_NAME                           = *0    ;

# Internals.

        *PERL_VERSION                           = *^V   ;
        *ACCUMULATOR                            = *^A   ;
        *COMPILING                              = *^C   ;
        *DEBUGGING                              = *^D   ;
        *SYSTEM_FD_MAX                          = *^F   ;
        *INPLACE_EDIT                           = *^I   ;
        *PERLDB                                 = *^P   ;
        *LAST_REGEXP_CODE_RESULT                = *^R   ;
        *EXCEPTIONS_BEING_CAUGHT                = *^S   ;
        *BASETIME                               = *^T   ;
        *WARNING                                = *^W   ;
        *EXECUTABLE_NAME                        = *^X   ;
        *OSNAME                                 = *^O   ;

# Deprecated.

#       *ARRAY_BASE                             = *[    ;
#       *OFMT                                   = *#    ;
#       *MULTILINE_MATCHING                     = **    ;
#       *OLD_PERL_VERSION                       = *]    ;

1;