sub::quote(3) [osx man page]

Sub::Quote(3)						User Contributed Perl Documentation					     Sub::Quote(3)

NAME

       Sub::Quote - efficient generation of subroutines via string eval

SYNOPSIS

	package Silly;

	use Sub::Quote qw(quote_sub unquote_sub quoted_from_sub);

	quote_sub 'Silly::kitty', q{ print "meow" };

	quote_sub 'Silly::doggy', q{ print "woof" };

	my $sound = 0;

	quote_sub 'Silly::dagron',
	  q{ print ++$sound % 2 ? 'burninate' : 'roar' },
	  { '$sound' => $sound };

       And elsewhere:

	Silly->kitty;  # meow
	Silly->doggy;  # woof
	Silly->dagron; # burninate
	Silly->dagron; # roar
	Silly->dagron; # burninate

DESCRIPTION

       This package provides performant ways to generate subroutines from strings.

SUBROUTINES

   quote_sub
	my $coderef = quote_sub 'Foo::bar', q{ print $x++ . "
" }, { '$x' =>  };

       Arguments: ?$name, $code, ?\%captures, ?\%options

       $name is the subroutine where the coderef will be installed.

       $code is a string that will be turned into code.

       "\%captures" is a hashref of variables that will be made available to the code.	See the "SYNOPSIS"'s "Silly::dagron" for an example using
       captures.

       options

       o no_install

	 Boolean.  Set this option to not install the generated coderef into the passed subroutine name on undefer.

   unquote_sub
	my $coderef = unquote_sub $sub;

       Forcibly replace subroutine with actual code.  Note that for performance reasons all quoted subs declared so far will be globally
       unquoted/parsed in a single eval. This means that if you have a syntax error in one of your quoted subs you may find out when some other
       sub is unquoted.

       If $sub is not a quoted sub, this is a no-op.

   quoted_from_sub
	my $data = quoted_from_sub $sub;

	my ($name, $code, $captures, $compiled_sub) = @$data;

       Returns original arguments to quote_sub, plus the compiled version if this sub has already been unquoted.

       Note that $sub can be either the original quoted version or the compiled version for convenience.

   inlinify
	my $prelude = capture_unroll {
	  '$x' => 1,
	  '$y' => 2,
	};

	my $inlined_code = inlinify q{
	  my ($x, $y) = @_;

	  print $x + $y . "
";
	}, '$x, $y', $prelude;

       Takes a string of code, a string of arguments, a string of code which acts as a "prelude", and a Boolean representing whether or not to
       localize the arguments.

   capture_unroll
	my $prelude = capture_unroll {
	  '$x' => 1,
	  '$y' => 2,
	};

       Generates a snippet of code which is suitable to be used as a prelude for "inlinify".  The keys are the names of the variables and the
       values are (duh) the values.  Note that references work as values.

CAVEATS

       Much of this is just string-based code-generation, and as a result, a few caveats apply.

   return
       Calling "return" from a quote_sub'ed sub will not likely do what you intend.  Instead of returning from the code you defined in
       "quote_sub", it will return from the overall function it is composited into.

       So when you pass in:

	  quote_sub q{	return 1 if $condition; $morecode }

       It might turn up in the intended context as follows:

	 sub foo {

	   <important code a>
	   do {
	     return 1 if $condition;
	     $morecode
	   };
	   <important code b>

	 }

       Which will obviously return from foo, when all you meant to do was return from the code context in quote_sub and proceed with running
       important code b.

perl v5.16.2							    2012-07-04							     Sub::Quote(3)

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code(n) 							    [incr Tcl]								   code(n)

NAME

       code - capture the namespace context for a code fragment

SYNOPSIS

       code ?-namespace name? command ?arg arg ...?

DESCRIPTION

       Creates	a  scoped  value  for  the specified command and its associated arg arguments.	A scoped value is a list with three elements:  the
       "@scope" keyword, a namespace context, and a value string.  For example, the command namespace foo {
	   code puts "Hello World!"  } produces the scoped value: @scope ::foo {puts {Hello World!}} Note that the code command captures the  cur-
       rent  namespace	context.   If  the  -namespace	flag is specified, then the current context is ignored, and the name string is used as the
       namespace context.

       Extensions like Tk execute ordinary code fragments in the global namespace.  A scoped value captures a  code  fragment  together  with  its
       namespace  context  in  a way that allows it to be executed properly later.  It is needed, for example, to wrap up code fragments when a Tk
       widget is used within a namespace: namespace foo {
	   private proc report {mesg} {
	       puts "click: $mesg"
	   }

	   button .b1 -text "Push Me"	      -command [code report "Hello World!"]
	   pack .b1 } The code fragment associated with button .b1 only makes sense in the context of namespace "foo".	Furthermore, the  "report"
       procedure  is private, and can only be accessed within that namespace.  The code command wraps up the code fragment in a way that allows it
       to be executed properly when the button is pressed.

       Also, note that the code command preserves the integrity of arguments on the command line.  This makes it a  natural  replacement  for  the
       list  command,  which  is often used to format Tcl code fragments.  In other words, instead of using the list command like this: after 1000
       [list puts "Hello $name!"]  use the code command like this: after 1000 [code puts "Hello $name!"]  This not only formats the  command  cor-
       rectly, but also captures its namespace context.

       Scoped  commands can be invoked like ordinary code fragments, with or without the eval command.	For example, the following statements work
       properly: set cmd {@scope ::foo .b1} $cmd configure -background red

       set opts {-bg blue -fg white} eval $cmd configure $opts Note that scoped commands by-pass the usual  protection	mechanisms;  the  command:
       @scope ::foo {report {Hello World!}} can be used to access the "foo::report" proc from any namespace context, even though it is private.

KEYWORDS

       scope, callback, namespace, public, protected, private

itcl									3.0								   code(n)

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sub::quote(3) [osx man page]

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