first cut at named parameters

[p5sagit/Function-Parameters.git] / lib / Function / Parameters.pm

diff --git a/lib/Function/Parameters.pm b/lib/Function/Parameters.pm
index c3d7125..8f58d15 100644 (file)
--- a/lib/Function/Parameters.pm
+++ b/lib/Function/Parameters.pm
@@ -9,7 +9,7 @@ use Carp qw(confess);
 
 use XSLoader;
 BEGIN {
-       our $VERSION = '0.09';
+       our $VERSION = '0.10_01';
        XSLoader::load;
 }
 
@@ -32,20 +32,25 @@ my %type_map = (
                name => 'optional',
                default_arguments => 1,
                check_argument_count => 0,
+               named_parameters => 1,
        },
        method   => {
                name => 'optional',
                default_arguments => 1,
                check_argument_count => 0,
+               named_parameters => 1,
                attrs => ':method',
                shift => '$self',
+               invocant => 1,
        },
        classmethod   => {
                name => 'optional',
                default_arguments => 1,
                check_argument_count => 0,
+               named_parameters => 1,
                attributes => ':method',
                shift => '$class',
+               invocant => 1,
        },
 );
 for my $k (keys %type_map) {
@@ -110,6 +115,8 @@ sub import {
                        : 1
                ;
                $clean{check_argument_count} = !!delete $type{check_argument_count};
+               $clean{invocant} = !!delete $type{invocant};
+               $clean{named_parameters} = !!delete $type{named_parameters};
 
                %type and confess "Invalid keyword property: @{[keys %type]}";
 
@@ -126,6 +133,8 @@ sub import {
                ;
                $flags |= FLAG_DEFAULT_ARGS if $type->{default_arguments};
                $flags |= FLAG_CHECK_NARGS if $type->{check_argument_count};
+               $flags |= FLAG_INVOCANT if $type->{invocant};
+               $flags |= FLAG_NAMED_PARAMS if $type->{named_parameters};
                $^H{HINTK_FLAGS_ . $kw} = $flags;
                $^H{HINTK_SHIFT_ . $kw} = $type->{shift};
                $^H{HINTK_ATTRS_ . $kw} = $type->{attrs};
@@ -183,12 +192,17 @@ Function::Parameters - subroutine definitions with parameter lists
  method set_name($name) {
    $self->{name} = $name;
  }
-
+ 
+ # method with explicit invocant
+ method new($class: %init) {
+   return bless { %init }, $class;
+ }
+ 
  # function with default arguments
  fun search($haystack, $needle = qr/^(?!)/, $offset = 0) {
    ...
  }
-
+ 
  # method with default arguments
  method skip($amount = 1) {
    $self->{position} += $amount;
@@ -198,6 +212,22 @@ Function::Parameters - subroutine definitions with parameter lists
 
 =pod
 
+ use Function::Parameters qw(:strict);
+ 
+ fun greet($x) {
+   print "Hello, $x\n";
+ }
+ 
+ greet "foo", "bar";
+ # Dies at runtime with "Too many arguments for fun greet"
+ 
+ greet;
+ # Dies at runtime with "Not enough arguments for fun greet"
+
+=cut
+
+=pod
+
  # use different keywords
  use Function::Parameters {
    proc => 'function',
@@ -214,11 +244,6 @@ Function::Parameters - subroutine definitions with parameter lists
 This module lets you use parameter lists in your subroutines. Thanks to
 L<PL_keyword_plugin|perlapi/PL_keyword_plugin> it works without source filters.
 
-WARNING: This is my first attempt at writing L<XS code|perlxs> and I have
-almost no experience with perl's internals. So while this module might
-appear to work, it could also conceivably make your programs segfault.
-Consider this module alpha quality.
-
 =head2 Basic stuff
 
 To use this new functionality, you have to use C<fun> instead of C<sub> -
@@ -318,6 +343,17 @@ Valid values: strings that look like a scalar variable. Any function created by
 this keyword will automatically L<shift|perlfunc/shift> its first argument into
 a local variable whose name is specified here.
 
+=item C<invocant>
+
+Valid values: booleans. This lets users of this keyword specify an explicit
+invocant, that is, the first parameter may be followed by a C<:> (colon)
+instead of a comma and will by initialized by shifting the first element off
+C<@_>.
+
+You can combine C<shift> and C<invocant>, in which case the variable named in
+C<shift> serves as a default shift target for functions that don't specify an
+explicit invocant.
+
 =item C<attributes>, C<attrs>
 
 Valid values: strings that are valid source code for attributes. Any value
@@ -412,6 +448,7 @@ C<'method'> is equivalent to:
    check_argument_count => 0,
    attributes => ':method',
    shift => '$self',
+   invocant => 1,
  }
 
 C<'method_strict'> is like C<'method'> but with
@@ -425,6 +462,7 @@ C<'classmethod'> is equivalent to:
    check_argument_count => 0,
    attributes => ':method',
    shift => '$class',
+   invocant => 1,
  }
 
 C<'classmethod_strict'> is like C<'classmethod'> but with
@@ -454,9 +492,10 @@ with C<(>).
 
 As an example, the following declaration uses every available feature
 (subroutine name, parameter list, default arguments, prototype, default
-attributes, attributes, argument count checks, and implicit C<$self>):
+attributes, attributes, argument count checks, and implicit C<$self> overriden
+by an explicit invocant declaration):
 
- method foo($x, $y, $z = sqrt 5)
+ method foo($this: $x, $y, $z = sqrt 5)
    :($$$;$)
    :lvalue
    :Banana(2 + 2)
@@ -470,7 +509,7 @@ And here's what it turns into:
    sub foo ($$$;$);
    Carp::croak "Not enough arguments for method foo" if @_ < 3;
    Carp::croak "Too many arguments for method foo" if @_ > 4;
-   my $self = shift;
+   my $this = shift;
    my ($x, $y, $z) = @_;
    $z = sqrt 5 if @_ < 3;
    ...