X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2FLexical-Types.git;a=blobdiff_plain;f=README;h=0d8a7a8877fb7c2628f3f1b5e3c5ad2e361d43d3;hp=bba2ba0abf2a26a97a95b0b3d9f78a1f47250147;hb=e969ec4cc563f70e92f4428bfc01528de9b8ceb9;hpb=e0816b772aa735946828e9486e8ab312fc8c92d8

diff --git a/README b/README
index bba2ba0..0d8a7a8 100644
--- a/README
+++ b/README
@@ -2,7 +2,7 @@ NAME
     Lexical::Types - Extend the semantics of typed lexicals.
 
 VERSION
-    Version 0.03
+    Version 0.04
 
 SYNOPSIS
         { package Str; }
@@ -31,10 +31,20 @@ SYNOPSIS
 
 DESCRIPTION
     This pragma allows you to hook the execution of typed lexicals
-    declarations ("my Str $x"). In particular, it can be used to
-    automatically tie or bless typed lexicals.
+    declarations ("my Str $x") by calling a configurable method in a
+    configurable package at each run. In particular, it can be used to
+    automatically tie or bless typed lexicals whenever they are initialized.
 
-    It is not implemented with a source filter.
+    Remind that for "perl" to be able to parse "my Str $x", you need :
+
+    *   either the "Str" package to be defined ;
+
+    *   or for "Str" to be a constant sub returning a valid defined package.
+
+    so make sure you follow one of those two strategies to define your
+    types.
+
+    This pragma is not implemented with a source filter.
 
 FUNCTIONS
   "import [ as => [ $prefix | $mangler ] ]"
@@ -73,14 +83,38 @@ FUNCTIONS
                 use Lexical::Types as => sub { 'My', 'new_' . lc($_[0]) };
                 my Str $x; # the coderef indicates to call My->new_str
 
-    The initializer method receives an alias to the pad entry of $x in $_[1]
-    and the original type name ("Str") in $_[2]. You can either edit $_[1]
-    in place, in which case you should return an empty list, or return a new
-    scalar that will be copied into $x.
+        Note that if the type is a constant, $_[0] will be set to the
+        *value* of constant and not to its name.
+
+            use Lexical::Types as => sub { $_[0] => 'new' };
+            use constant Str => 'MyStr';
+            my Str $x; # calls MyStr->new
+
+        This means in particular that you can't both use constant types and
+        redirect several types to different methods of the same package,
+        because then you can't distinguish between the original types with
+        $_[0].
 
   "unimport"
     Magically called when writing "no Lexical::Types". Turns the pragma off.
 
+RUN-TIME INITIALIZER METHOD
+    The initializer method receives an alias to the pad slot of the
+    initialized lexical in $_[1] and the original type name in $_[2]. You
+    can either edit $_[1] in place, in which case you should return an empty
+    list, or return a new scalar that will be copied into the pad slot.
+
+        use Lexical::Types as => 'My';
+
+        my Str $x;
+
+        ...
+
+        sub My::Str::TYPEDSCALAR {
+         # $_[1] is an alias to $x, and $_[2] is 'Str'
+         ...
+        }
+
 INTEGRATION
     You can integrate Lexical::Types in your module so that using it will
     provide types to your users without asking them to load either
@@ -105,6 +139,38 @@ INTEGRATION
 
         sub new_int { ... }
 
+    If you prefer to use constants rather than creating empty packages, you
+    can replace the previous example with something like this :
+
+        package MyTypes;
+
+        BEGIN { require Lexical::Types; }
+
+        sub import {
+         my $pkg = caller;
+         for (qw/Str Int/) {
+          my $type = __PACKAGE__ . '::' . $_;
+          no strict 'refs';
+          no warnings 'redefine';
+          *{$pkg.'::'.$_} = eval "sub () { '$type' }";
+         }
+         Lexical::Types->import(
+          as => sub { $_[0] => 'new' }
+         );
+        }
+
+        sub unimport {
+         Lexical::Types->unimport;
+        }
+
+        package MyTypes::Str;
+
+        sub new { ... }
+
+        package MyTypes::Int;
+
+        sub new { ... }
+
 CAVEATS
     For "perl" to be able to parse "my Str $x", you need :
 
@@ -112,9 +178,10 @@ CAVEATS
 
     *   or for "Str" to be a constant sub returning a valid defined package.
 
-    Those restrictions apply even if you use the 'as' option to redirect to
-    another package, and are unlikely to find a workaround as this happens
-    deep inside the lexer - far from the reach of an extension.
+    The restrictions on the type (being either a defined package name or a
+    constant) apply even if you use the 'as' option to redirect to another
+    package, and are unlikely to find a workaround as this happens deep
+    inside the lexer - far from the reach of an extension.
 
     Only one mangler or prefix can be in use at the same time in a given
     scope.