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| <title>S28-special-names.pod</title> | |
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| <h1>S28-special-names.pod</h1> | |
| Path: <a href="http://autoexec.demon.nl:2080/">(root)</a> / | |
| <a href="http://autoexec.demon.nl:2080/home">home</a> / | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo">rakudo</a> / | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs">pugs</a> / | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs">docs</a> / | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6">Perl6</a> / | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec">Spec</a><br> | |
| <table><tbody><tr> | |
| <td> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S32-setting-library">S32-setting-library/</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S01-overview.pod">S01-overview.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S02-bits.pod">S02-bits.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S03-operators.pod">S03-operators.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S04-control.pod">S04-control.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S05-regex.pod">S05-regex.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S06-routines.pod">S06-routines.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S07-iterators.pod">S07-iterators.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S09-data.pod">S09-data.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S10-packages.pod">S10-packages.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S11-modules.pod">S11-modules.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S12-objects.pod">S12-objects.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S13-overloading.pod">S13-overloading.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S14-roles-and-parametric-types.pod">S14-roles-and-parametric-types.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S16-io.pod">S16-io.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S17-concurrency.pod">S17-concurrency.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S19-commandline.pod">S19-commandline.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S21-calling-foreign-code.pod">S21-calling-foreign-code.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S22-package-format.pod">S22-package-format.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S26-documentation.pod">S26-documentation.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S28-special-names.pod">S28-special-names.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S29-functions.pod">S29-functions.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/S31-pragmatic-modules.pod">S31-pragmatic-modules.pod</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/update">update</a><br> | |
| <a href="http://autoexec.demon.nl:2080/home/rakudo/pugs/docs/Perl6/Spec/update.bat">update.bat</a><br> | |
| </td> | |
| <td id="pod"> | |
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| </style> | |
| <h1>Name</h1> | |
| <pre> | |
| [DRAFT] Synopsis 28 - Special Names [DRAFT] | |
| </pre> | |
| <h1>Version</h1> | |
| <pre> | |
| Author: Larry Wall <[email protected]> | |
| Maintainer: Larry Wall <[email protected]> | |
| Contributions: Tim Nelson <[email protected]> | |
| Date: 23 Feb 2009, created by Tim Nelson from miscellaneous documents lying around | |
| Last Modified: 25 Feb 2009 | |
| Version: 5 | |
| </pre> | |
| <h1>Special Variables</h1> | |
| <h2>Introduction</h2> | |
| <p>This document serves as a collection point for what is known about | |
| special variables in Perl 6 and correlates them with the changes from Perl | |
| 5. </p> | |
| <p>If you are trying to find the Perl 6 equivalent of a Perl 5 special | |
| variable you know, try searching this file for the Perl 5 version. Each | |
| main entry is followed by a note containing the corresponding Perl 5 | |
| variable(s). The list of main entries is also followed by a table showing | |
| the 5 and 6 variables side-by-side.</p> | |
| <h2>Overview</h2> | |
| <h3>Secondary Sigils (also known as "twigils")</h3> | |
| <p>A quick reminder of the relevant twigils from S02:</p> | |
| <pre> | |
| $?foo # Compiler constants (fixed at compile time) | |
| $*foo # Context variable, default global (run time) | |
| $=foo # File-scoped POD data | |
| </pre> | |
| <p>The various <code>$?foo</code> variables are determined at compile time, | |
| and are not modifiable at run time. This does not mean that the variable | |
| has the same value everywhere; for instance, <code>$?LINE</code> is | |
| different on every line of the program.</p> | |
| <p>The <code>$*foo</code> variables function both as dymamically scoped | |
| variables and as globals. Globalness is relative, in other words. Any | |
| dynamic scope may modify the set of globals visible via the <code>$*foo | |
| </code> notation. Most of the standard globals listed below actually live | |
| either in the <code>PROCESS</code> or the <code>GLOBAL</code> package, | |
| where <code>PROCESS</code> contains globals belonging to the entire | |
| process, while <code>GLOBAL</code> contains the globals belonging to the | |
| current interpreter, since a process may be running more than one | |
| interpreter. Unless otherwise indicated below, the outermost definition of | |
| these variables are kept in the <code>PROCESS</code>package.</p> | |
| <p>The <code>$=foo</code> variables are related to the the <code>$?foo | |
| </code> variables insofar as the text of the program is known at compile | |
| time, so the values are static. However, the different twigil indicates | |
| that the variable contains POD data, which is primarily under user control | |
| rather than compiler control. The structure of these variables will be | |
| fleshed out in S26.</p> | |
| <h3>Named variables</h3> | |
| <pre> | |
| Variable Spec Type Description | |
| -------- ---- ---- ----------- | |
| </pre> | |
| <pre> | |
| @_ # ??? | |
| $! S04 # Current Exception object | |
| $/ S05 Match # Last match | |
| $0, $1, $2 S05 Str # First captured value from match: $/[0] | |
| $?ARCH SoftwarePackage # Host architecture | |
| $?XARCH SoftwarePackage # Target architecture | |
| @*ARGS S06 Array of Str # command-line arguments | |
| $*ARGFILES S02 IO # The magic command-line input handle | |
| &?BLOCK S06 Block # current block (itself) | |
| ::?CLASS S12 Str # current class (as package or type name) | |
| $?CLASS S02 Class # current class | |
| @=COMMENT (S26) # All the comment blocks in the file | |
| %?CONFIG Hash of XXX # configuration hash XXX What does this do? | |
| $=DATA (S26) IO # data block handle (=begin DATA ... =end) | |
| @=DATA (S26) Array # Same as above, but array | |
| %?DEEPMAGIC S13 Hash of XXX # Controls the mappings of magical names to sub definitions | |
| $?DISTRO S02 SoftwarePackage # Which OS distribution am I compiling under | |
| $*DISTRO S02 SoftwarePackage # Which OS distribution am I running under | |
| $*EGID Int # effective group id | |
| %*ENV S02 Hash of Str # system environment variables | |
| $*ERR S16 IO # Standard error handle | |
| $*EUID Int # effective user id | |
| $*EXECUTABLE_NAME Str # executable name | |
| $?FILE S02 Str # current filename of source file | |
| $?GRAMMAR S02 Grammar # current grammar | |
| $*GID Int # group id | |
| $*IN S16 IO # Standard input handle; is an IO object | |
| $*INC S11 # where to search for user modules (but not std lib!) | |
| $?LANG S02 # Which Perl parser should embedded closures parse with? | |
| $*LANG S02 Str # LANG variable from %*ENV that defines what human language is used | |
| $?LINE S02 Int # current line number in source file | |
| %*META-ARGS S19 Hash of XXX # Meta-arguments | |
| $?MODULE S02 Module # current module | |
| %*OPTS S19 Hash of XXX # Options from command line | |
| %*OPT... S19 Hash of XXX # Options from command line to be passed down | |
| $?KERNEL SoftwarePackage # operating system compiled for | |
| $*KERNEL SoftwarePackage # operating system running under | |
| $*OUT S16 IO # Standard output handle | |
| $?PARSER S02 Grammar # Which Perl grammar was used to parse this statement? | |
| $?PACKAGE S02 Package # current package | |
| $?PERL S02 SoftwarePackage # Which Perl am I compiled for? | |
| $*PERL S02 SoftwarePackage # perl version running under | |
| $*PID Int # system process id | |
| %=POD S02 # (or some such) | |
| $*PROGRAM_NAME S19 Str # name of the Perl program being executed | |
| %*PROTOCOLS S16 Hash of Method # Stores the methods needed for the uri() function | |
| ::?ROLE Str # current role (as package or type name) | |
| $?ROLE S02 Role # current role | |
| &?ROUTINE S06 Routine # current sub or method (itself) | |
| $?SCOPE S02 # Current "my" scope (XXX unnecessary?) | |
| $*UID Int # system user id | |
| $?USAGE S06 Str # Default usage message generated at compile time | |
| $?VM S02 SoftwarePackage # Which virtual machine am I compiling under | |
| $?XVM S02 SoftwarePackage # Which virtual machine am I cross-compiling for | |
| </pre> | |
| <p>Note that contextual variables such as <code>$*OUT</code> may have more | |
| than one current definition in the outer dynamic context, in which case the | |
| innermost dynamic scope determines the meaning. For instance, <code> | |
| $PROCESS::OUT</code> is the stdout for the entire process, but each | |
| interpreter can set its own <code>$GLOBAL::OUT</code> to make <code>$*OUT | |
| </code> mean whatever it wants independently of other interpreters. Any | |
| dynamic scope may also declare a local meaning of <code>$*OUT</code> that | |
| applies only to called code. Likewise each thread could log its own errors | |
| to its own <code>$*ERR</code>, since a thread is a dynamic scope.</p> | |
| <h2>Special Classes</h2> | |
| <p>These are classes defined especially for the benefit of the Special | |
| Variables. </p> | |
| <pre> | |
| class SoftwarePackage { | |
| has Str $name; | |
| has Version $version; | |
| } | |
| </pre> | |
| <p>This class is intended to represent a software package at a fairly basic | |
| level. </p> | |
| <h3>Perl5 to Perl6 special variable translation</h3> | |
| <p>If a column has a "-" in it, it means that item is unavailable in that | |
| version of Perl. </p> | |
| <pre> | |
| Perl 5 Perl 6 Comment | |
| ----------- ----------- ----------------------- | |
| STDIN $*IN See S16; actual variable is $PROCESS::IN | |
| STDOUT $*OUT See S16; actual variable is $PROCESS::OUT | |
| STDERR $*ERR See S16; actual variable is $PROCESS::ERR | |
| $_ $ARG $_ More lexically aware | |
| $_[1],$_[2].. $^a,$^b.. | |
| $a,$b - Just params to anonymous block | |
| - $/ Object with results of last regex match | |
| $1,$2,$3... $1,$2,$3... | |
| $& $MATCH $<> | |
| $` $PREMATCH substr based on $/.from | |
| $' $POSTMATCH substr based on $/.to | |
| $+ - But info can now be retrieved from $/ | |
| $^N $*MOST_RECENT_CAPTURED_MATCH ...or some such. | |
| or $/[*-$n] ...or omit | |
| @- $1.start, etc | |
| @+ $1.end, etc. | |
| %! - | |
| $[ - This feature has been removed | |
| $* - Deprecated long ago | |
| $# - Deprecated long ago | |
| $^H - These were only ever internal anyway | |
| %^H - | |
| - $! Current exception (see | |
| S04-control | |
| ) | |
| $! $ERRNO $OS_ERROR - Use shiny new $! | |
| $? $CHILD_ERROR - Use shiny new $! | |
| $@ $EVAL_ERROR - Use shiny new $! | |
| $^E - Use shiny new $! | |
| $^S - | |
| $. $NR $*IN.input_record_number() | |
| $/ $RS $*IN.input_record_separator() | |
| $| $*OUT.autoflush() | |
| $, $OFS $*OUT.output_field_separator() | |
| $\ $*OUT.output_record_separator() | |
| $" $LIST_SEPARATOR - | |
| $; $SUBSEP - | |
| $$ $PID $*PID | |
| $< $UID $*UID Real UID (User ID) | |
| $( $GID $*GID Real GID (Group ID) | |
| $> $EUID $*EUID Effective UID | |
| $) $EGID $*EGID Effective GID | |
| $0 $PROGRAM_NAME $*PROGRAM_NAME | |
| $^C $COMPILING $*COMPILING | |
| $^D $DEBUGGING $*DEBUGGING | |
| $^F $SYS_FD_MAX $*SYS_FD_MAX ...or some such | |
| $^I $INPLACE_EDIT $*INPLACE_EDIT ...or some such | |
| $^M $*EMERGENCY_MEMORY ...or some such (or omit) | |
| $^O $OSNAME $*OSNAME ...or some such | |
| $^P $PERLDB $*PERLDB ...or some such | |
| $^R $*LAST_REGEXP_CODE_RESULT ...or some such. Or omit. | |
| $^T $BASETIME $*INITTIME A Temporal::Instant object | |
| $^V $] $?PERL.version | |
| $^W $*WARNINGS (if any dynamic control needed) | |
| ${^WARNING_BITS} $?WARNINGS | |
| $^X $*EXECUTABLE_NAME ...or some such | |
| ARGV $*ARGS Note the P6 idiom for this handle: | |
| for =$*ARGS { | |
| # each time through loop | |
| # proc a line from files named in ARGS | |
| } | |
| @ARGV @*ARGS | |
| ARGVOUT TBD | |
| $ARGV TBD | |
| @F @_ | |
| %ENV %*ENV | |
| @INC @*INC (but not for std library modules) | |
| %INC %*INC (maybe, if needed) | |
| %SIG event filters plus exception translation | |
| $SIG{__WARN__} $*ON_WARN | |
| $SIG{__DIE__} $*ON_DIE | |
| ${^OPEN} - This was internal; forget it | |
| <a href="http://perldoc.perl.org/S04-control.html">S04-control</a> | |
| </pre> | |
| <h2>NOT YET DEFINED</h2> | |
| <p>The following items are not yet defined, but will need to be defined. | |
| </p> | |
| <p>XXX Don't remove this line until this section is completely blank. </p> | |
| <p>We also seem to have $*INC in the table at the top, @*INC in S19 and the | |
| table immediately above, %*INC also in the table above. </p> | |
| <p>The $?LANG and $*LANG variables are also confusing (both in S02). </p> | |
| <h3>Form.pm</h3> | |
| <p>These go in the Perl5 to Perl6 conversion table:</p> | |
| <pre> | |
| Perl6 Perl5 | |
| ----- ----------------------------------------- | |
| - $% $FORMAT_PAGE_NUMBER | |
| - HANDLE->format_page_number(EXPR) | |
| </pre> | |
| <pre> | |
| - $= $FORMAT_LINES_PER_PAGE | |
| - HANDLE->format_lines_per_page(EXPR) | |
| </pre> | |
| <pre> | |
| - $- $FORMAT_LINES_LEFT | |
| - HANDLE->format_lines_left(EXPR) | |
| </pre> | |
| <pre> | |
| - $~ $FORMAT_NAME | |
| - HANDLE->format_name(EXPR) | |
| </pre> | |
| <pre> | |
| - $^ $FORMAT_TOP_NAME | |
| - HANDLE->format_top_name(EXPR) | |
| </pre> | |
| <pre> | |
| - $: $FORMAT_LINE_BREAK_CHARACTERS | |
| - IO::Handle->format_line_break_characters | |
| </pre> | |
| <pre> | |
| - $^L $FORMAT_FORMFEED | |
| - IO::Handle->format_formfeed | |
| </pre> | |
| <pre> | |
| - $^A $ACCUMULATOR | |
| </pre> | |
| <h3>S15-unicode.pod</h3> | |
| <p>${^ENCODING} variable -- S32/Str.pod implies this is $*ENC ${^UNICODE} | |
| variable</p> | |
| <h3>Infectious trait spec</h3> | |
| <p>${^TAINT} variable, which is pending, among other things, infectious | |
| trait spec</p> | |
| <h1>Additions</h1> | |
| <p>Please post errors and feedback to perl6-language. If you are making a | |
| general laundry list, please separate messages by topic.</p> | |
| <p>=for vim:set expandtab sw=4:</p> | |
| </td> | |
| </tr></tbody></table> | |
| </body></html> |
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