# (X)Emacs mode: -*- cperl -*- package Class::MethodMaker; =head1 NAME Class::MethodMaker - a module for creating generic methods =head1 SYNOPSIS use Class::MethodMaker new_with_init => 'new', get_set => [ qw /foo bar baz / ]; =head1 DESCRIPTION This module solves the problem of having to write a bazillion get/set methods that are all the same. The argument to 'use' is a hash whose keys are the names of types of generic methods generated by MethodMaker and whose values tell method maker what methods to make. (More precisely, the keys are the names of MethodMaker methods (methods that write methods) and the values are the arguments to those methods. To override any generated methods, it is sufficient to ensure that the overriding method is defined when Class::MethodMaker is called. Note that the C keyword introduces a C block, so you may need to define (or at least declare) your overriding method in a C block. Some new facilities may be marked as EXPERIMENTAL in the documentation. These facilities are being trialled, and whilst it is hoped that they will become mainstream code, no promises are made. They may change or disappear at any time. Caveat Emptor. The maintainer would be delighted to hear any feedback particularly regarding such facilities, be it good or bad, so long as it is constructive. Some old facilities may be marked as COMPATIBILITY in the documentation. These facilities are being maintained purely for compatibility with old versions of this module, but will ultimately disappear. They are normally replaced by alternatives that are thought preferable for some completely arbitrary raisin. Please avoid using them, and consider amending any existing code that does use them not to. If you believe that their removal will cast an unacceptable pall over your life, please contact the maintainer, or get a new life: whichever is easier. =cut # ---------------------------------------------------------------------------- # Pragmas ----------------------------- require 5.00307; # for the ->isa method. use strict; # Inheritance ------------------------- use AutoLoader; use vars qw( @ISA ); @ISA = qw ( AutoLoader ); # Utility ----------------------------- use Carp qw( carp cluck croak ); use vars qw( $VERSION $PACKAGE ); $VERSION = '1.05'; $PACKAGE = 'Class-MethodMaker'; # ---------------------------------------------------------------------- # Just to point out the existence of these variables use vars '%BooleanPos', # A hash of the current index into the bit vector # used in boolean for each class. '%BooleanFields', # A hash of refs to arrays which store the names of # the bit fileds for a given class '%StructPos', # A hash of the current index into the arry used in # struct for each class. '%StructFields'; # A hash of refs to arrays which store the names of # the struct fields for a given class sub ima_method_maker { 1 }; sub find_target_class { # Find the class to add the methods to. I'm assuming that it would be # the first class in the caller() stack that's not a subsclass of # MethodMaker. If for some reason a sub-class of MethodMaker also # wanted to use MethodMaker it could redefine ima_method_maker to # return a false value and then $class would be set to it. my $class; my $i = 0; while (1) { $class = (caller($i))[0]; ( $class->isa('Class::MethodMaker') and &{$class->can ('ima_method_maker')} ) or last; $i++; } return $class; } # ------------------------------------- sub import { my ($class, @args) = @_; # XXX Deprecated 25.v.00 --------- # This code is dangerous (pollutes # external namespace) and deprecated. Use at your peril. It is not # supported, and will disappear at or after 25.v.01 if (defined $args[0] and $args[0] eq '-sugar') { shift @args; *methods:: = *Class::MethodMaker::; } # XXX Deprecated 25.v.00 --------- @args and $class->make(@args); } # ------------------------------------- sub make { my ($method_maker_class, @args) = @_; my $TargetClass = $method_maker_class->find_target_class; # We have to initialize these before we run any of the # meta-methods. (At least the anon lists, so they get captured properly # in the closures. $BooleanPos{$TargetClass} ||= 0; $BooleanFields{$TargetClass} ||= []; $StructPos{$TargetClass} ||= 0; $StructFields{$TargetClass} ||= []; # make generic methods. The list passed to import should alternate # between the names of the meta-method to call to generate the methods # and either a scalar arg or a ARRAY ref to a list of args. # Each meta-method is responsible for calling install_methods() to get # it's methods installed. my ($meta_method, $arg); while (1) { $meta_method = shift @args or last; $arg = shift @args or croak "No arg for $meta_method in import of $method_maker_class.\n"; my @args = ref($arg) eq 'ARRAY' ? @$arg : ($arg); $method_maker_class->$meta_method(@args); } return; } # ------------------------------------- sub install_methods { my ($class, %methods) = @_; no strict 'refs'; # print STDERR "CLASS: $class\n"; my $TargetClass = $class->find_target_class; my $package = $TargetClass . "::"; my ($name, $code); while (($name, $code) = each %methods) { # add the method unless it's already defined (which should only # happen in the case of static methods, I think.) my $reftype = ref $code; if ( $reftype eq 'CODE' ) { *{"$package$name"} = $code unless defined *{"$package$name"}{CODE}; } elsif ( ! $reftype ) { my $coderef = eval $code; croak "Code:\n$code\n\ndid not compile: $@\n" if $@; croak "String:\n$code\n\ndid not eval to a code ref: $coderef\n" unless ref $coderef eq 'CODE'; *{"$package$name"} = $coderef unless defined *{"$package$name"}{CODE}; } else { croak "What do you expect me to do with this?: $code\n"; } } } 1; # keep require happy # ---------------------------------------------------------------------------- __END__ # AutoLoaded Methods =head1 SUPPORTED METHOD TYPES =head2 new Creates a basic constructor. Takes a single string or a reference to an array of strings as its argument. For each string creates a simple method that creates and returns an object of the appropriate class. This method may be called as a class method, as usual, or as in instance method, in which case a new object of the same class as the instance will be created. I works slightly differently with regard to being called on an instance.> =cut sub new { my ($class, @args) = @_; my %methods; foreach (@args) { $methods{$_} = sub { my $class = shift; $class = ref $class || $class; my $self = {}; bless $self, $class; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 new_with_init Creates a basic constructor which calls a method named C after instantiating the object. The C method should be defined in the class using MethodMaker. Takes a single string or a reference to an array of strings as its argument. For each string creates a simple method that creates an object of the appropriate class, calls C on that object propagating all arguments, before returning the object. This method may be called as a class method, as usual, or as in instance method, in which case a new object of the same class as the instance will be created. I works slightly differently with regard to being called on an instance.> =cut sub new_with_init { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; $methods{$field} = sub { my $class = shift; $class = ref $class || $class; my $self = {}; bless $self, $class; $self->init (@_); $self; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 new_hash_init Creates a basic constructor which accepts a hash of slot-name/value pairs with which to initialize the object. The slot-names are interpreted as the names of methods that can be called on the object after it is created and the values are the arguments to be passed to those methods. Takes a single string or a reference to an array of strings as its argument. For each string creates a method that takes a list of arguments that is treated as a set of key-value pairs, with each such pair causing a call C<$self-Ekey ($value)>. This method may be called as a class method, causing a new instance to be created, or as an instance method, which will operate on the subject instance. This allows it to be combined with new_with_init (see above) to provide some default values. For example, declare a new_with_init method, say 'new' and a new_hash_init method, for example, 'hash_init' and then in the init method, you can call modify or add to the %args hash and then call hash_init. I and C differently with regard to being called on an instance.> =cut sub new_hash_init { my ($class, @args) = @_; my %methods; foreach (@args) { $methods{$_} = sub { my $class = shift; my $self = ref ($class) ? $class : bless {}, $class; # Accept key-value attr list, or reference to unblessed hash of # attr my %args = (scalar @_ == 1 and ref($_[0]) eq 'HASH') ? %{ $_[0] } : @_; foreach (keys %args) { $self->$_($args{$_}); } $self; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------------- =head2 new_with_args Creates a basic constructor. Takes a single string or a reference to an array of strings as its argument. For each string creates a simple method that creates and returns an object of the appropriate class. This method may be called as a class method, as usual, or as in instance method, in which case a new object of the same class as the instance will be created. I works slightly differently with regard to being called on an instance.> Constructor arguments will be stored as a key, value pairs in the object. No check is done regarding the consistencies of the data passed to the constructor and the accessor methods created. =cut # added by Dominique Dumont (22.i.02) sub new_with_args { my ($class, @args) = @_; my %methods; foreach (@args) { $methods{$_} = sub { my $class = shift; my @c_args = @_ ; $class = ref $class || $class; my $self = { @c_args }; bless $self, $class; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 get_set Takes a single string or a reference to an array of strings as its argument. Each string specifies a slot, for which accessor methods are created. The accessor methods are, by default: =over 4 =item x If an argument is provided, sets a new value for x. This is true even if the argument is undef (cf. no argument, which does not set.) Returns (new) value. Value defaults to undef. =item clear_x Sets value to undef. This is exactly equivalent to $foo->x (undef) No return. =back This is your basic get/set method, and can be used for slots containing any scalar value, including references to non-scalar data. Note, however, that MethodMaker has meta-methods that define more useful sets of methods for slots containing references to lists, hashes, and objects. =head2 EXPERIMENTAL: Options There are several options available for controlling the names and types of methods created. The following options affect the type of methods created: =over 4 =item -static The methods will refer to a class-specific, rather than instance-specific store. I.e., these scalars are shared across all instances of your object in your process. =back The following options affect the methods created as detailed: =over 4 =item -java Creates getx and setx methods, which return the value, and set the value (no return), respectively. =item -eiffel Creates x and set_x methods, analogous to -java get_x and set_x respectively. =item -compatibility Creates x (as per the default), and clear_x, which resets the slot value to undef. Use this to ensure backward compatibility. =item -noclear Creates x (as per the default) only. =back Alternatively, an arrayref specifying a template for method names may be supplied. Each name must contain a '*' character, which will be replaced by the slot name, and no two patterns may be the same. undef may be supplied for methods that you do not want created. Currently, the first 4 members of such an arrayref may be used: =over 4 =item 0 Creates a method that if supplied an argument, sets the slot to the value of that argument; the value of the slot (after setting, if relevant) is returned. =item 1 Creates a method that takes no arguments, sets the slot value to undefined, and makes no return. =item 2 Creates a method that takes no arguments, and returns the value of the slot. =item 3 Creates a method that takes one argument, and sets the value of the slot to that value. Given undef as that argument, the value is set to undef. If called with no arguments, the slot value is set to undef. =back See the examples. =head2 Examples Creates methods a, b, c which can be used for both getting and setting the named slots: use Class::MethodMaker get_set => 'a', get_set => [qw/ b c /]; Creates get_d which returns the value in slot d (takes no arguments), and set_d, which sets the value in slot d (no return): use Class::MethodMaker get_set => [ -java => d ]; Creates e_clear, e_get, e_set, f_clear, f_get, f_set methods: use Class::MethodMaker get_set => [[undef, '*_clear', '*_get', '*_set'] => qw/e f/ ]; =cut sub _make_get_set { my $class = shift; my ($slot, $template, $static) = @_; my %methods; my @method_names = @$template; my $method_name; for $method_name (@method_names) { if ( defined $method_name ) { $method_name =~ s/\*/$slot/g or carp "Method name template must include \* character."; } } my $pgsetter; if ( $static ) { my $store; $pgsetter = sub { my $self = shift; if ( @_ ) { $store = shift; } else { $store; } }; } else { $pgsetter = sub { my $self = shift; if ( @_ ) { $self->{$slot} = shift; } else { $self->{$slot}; } }; } my @methods = ( '$pgsetter', 'sub { $pgsetter->($_[0], undef); return }', 'sub { return $pgsetter->($_[0]); }', 'sub { $pgsetter->($_[0], $_[1]); return }', ); my $i; for ($i = 0; $i < @methods; $i++) { $methods{$method_names[$i]} = eval $methods[$i] if defined $method_names[$i]; } return %methods; } use constant GS_PATTERN_MAP => { java => [ undef, undef, 'get*', 'set*' ], eiffel => [ undef, undef, '*', 'set_*' ], compatibility => [ '*', 'clear_*', undef, undef ], noclear => [ '*', undef, undef, undef ], }; use constant GS_PATTERN_SPEC => join '|', keys %{GS_PATTERN_MAP()}; sub get_set { my ($class, @args) = @_; my @methods; # @template is a list of pattern names for the methods. # Postions are perl:get/set, clear, get, set my $template = ${GS_PATTERN_MAP()}{'compatibility'}; my $static = 0; my $arg; foreach $arg (@args) { if ( my $ref = ref $arg ) { if ( $ref eq 'ARRAY' ) { $template = $arg; # Check for duplicate patterns. my %patterns; for (grep defined, @$template) { croak "Duplicate pattern: $_" if $patterns{$_}; $patterns{$_}++; } } else { croak "get_set does not handle this ref type: $ref"; } } elsif ( substr ($arg, 0, 1) eq '-' ) { my $opt_name = substr ($arg, 1); if ( exists ${GS_PATTERN_MAP()}{$opt_name} ) { $template = ${GS_PATTERN_MAP()}{$opt_name}; } elsif ( $opt_name eq 'static' ) { $static = 1; } else { croak "Unrecognised option: $opt_name to get_set"; } } else { push @methods, $class->_make_get_set ($arg, $template, $static); } } $class->install_methods (@methods); } # ---------------------------------------------------------------------- =head2 static_get_set Like L, takes a single string or a reference to an array of strings as its argument. For each string, x creates two methods: =over 4 =item x If an argument is provided, sets a new value for x. Returns (new) value. Value defaults to undef. =item clear_x Sets value to undef. No return. =back The difference between this and L is that these scalars are shared across all instances of your object in your process. This is now a wrapper around get_set (-static => @args). =cut sub static_get_set { return $_[0]->get_set (-static => @_[1..$#_]); } # ---------------------------------------------------------------------- =head2 get_concat Like get_set except sets do not clear out the original value, but instead concatenate the new value to the existing one. Thus these slots are only good for plain scalars. Also, like get_set, defines clear_foo method. The argument taken may be a hashref, in which the keys C and C are recognized; C being the slot name, join being a join string t glue any given strings. Example: use Class::MethodMaker get_concat => { name => 'words', join => "\t" }; Will, each time an argument is supplied to the C method, glue this argument onto any existing value with tab separator. Like the C operator, the join field is applied I values, not prior to the first or after the last. =cut sub get_concat { my ($class, @args) = @_; my %methods; foreach (@args) { my ($name, $join) = ($_, ''); if ( ref ($name) eq 'HASH' ) { die "get_concat requires name field" if ! exists $_->{'name'}; $name = $_->{'name'}; $join = $_->{'join'} || ''; } $methods{$name} = sub { my ($self, $new) = @_; if ( defined $new ) { if ( defined $self->{$name} ) { $self->{$name} = join $join, $self->{$name}, $new; } else { $self->{$name} = $new; } } # If returning undef upsets people, *return* '', but don't set --- # setting causes problems where join starts adding join fields # at start... $self->{$name}; }; $methods{"clear_$name"} = sub { my ($self) = @_; $self->{$name} = undef; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 grouped_fields Creates get/set methods like get_set but also defines a method which returns a list of the slots in the group. grouped_fields methods some_group => [ qw / field1 field2 field3 / ]; Its argument list is parsed as a hash of group-name => field-list pairs. Get-set methods are defined for all the fields and a method with the name of the group is defined which returns the list of fields in the group. =cut sub grouped_fields { my ($class, %args) = @_; my %methods; foreach (keys %args) { my @slots = @{$args{$_}}; $class->get_set(@slots); $methods{$_} = sub { @slots }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 object Creates methods for accessing a slot that contains an object of a given class as well as methods to automatically pass method calls onto the object stored in that slot. object => [ 'Foo' => 'phooey', 'Bar' => [ qw / bar1 bar2 bar3 / ], 'Baz' => { slot => 'foo', comp_mthds => [ qw / bar baz / ] }, 'Fob' => [ { slot => 'dog', comp_mthds => 'bark', }, { slot => 'cat', comp_mthds => 'miaow', }, ]; ]; The main argument should be a reference to an array. The array should contain pairs of class => sub-argument pairs. The sub-arguments parsed thus: =over 4 =item Hash Reference See C above. The hash should contain the following keys: =over 4 =item slot The name of the instance attribute (slot). =item comp_mthds A string or array ref, naming the methods that will be forwarded directly to the object in the slot. =back =item Array Reference As for C, for each member of the array. Also works if each member is a hash reference (see C above). =item String The name of the instance attribute (slot). =back For each slot C, with forwarding methods C and C, the following methods are created: =over 4 =item x A get/set method. If supplied with an object of an appropriate type, will set set the slot to that value. Else, if the slot has no value, then an object is created by calling new on the appropriate class, passing in any supplied arguments. The stored object is then returned. =item y Forwarded onto the object in slot C, which is auto-created via C if necessary. The C, if called, is called without arguments. =item z As for C. =back So, using the example above, a method, C, is created in the class that calls MethodMaker, which can get and set the value of those objects in slot foo, which will generally contain an object of class Baz. Two additional methods are created in the class using MethodMaker, named 'bar' and 'baz' which result in a call to the 'bar' and 'baz' methods on the Baz object stored in slot foo. =cut sub object { my ($class, @args) = @_; my %methods; while (@args) { my $class = shift @args; my $list = shift @args or die "No slot names for $class"; # Allow a list of hashrefs. my @list = ( ref($list) eq 'ARRAY' ) ? @$list : ($list); my $ref = ref $list; my $obj_def; foreach $obj_def (@list) { my $type = $class; # Hmmm. We have to do this for the closure to # work. I.e. using $class in the closure dosen't # work. Someday I'll actually understand scoping # in Perl. [ Uh, is this true? 11/11/96 -PBS ] my ($name, @composites); my $new_meth = 'new'; if ( ! ref $obj_def ) { $name = $obj_def; } else { $name = $obj_def->{'slot'}; my $composites = $obj_def->{'comp_mthds'}; @composites = ref($composites) eq 'ARRAY' ? @$composites : defined $composites ? ($composites) : (); } my $meth; foreach $meth (@composites) { $methods{$meth} = sub { my ($self, @args) = @_; $self->$name()->$meth(@args); }; } $methods{$name} = sub { my ($self, @args) = @_; if (ref $args[0] and UNIVERSAL::isa($args[0], $class)) { $self->{$name} = $args[0]; } else { defined $self->{$name} or $self->{$name} = $type->new(@args); } $self->{$name}; }; $methods{"delete_$name"} = sub { my ($self) = @_; $self->{$name} = undef; }; } } $class = $class; # Huh? Without this line the next line doesn't work! $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 object_list Functions like C, but maintains an array of referenced objects in each slot. Forwarded methods return a list of the results returned by Cing the method over each object in the array. Arguments are like C. =cut sub object_list { my ($class, @args) = @_; my %methods; while (@args) { # DD: changed to $obj_class to avoid clobberring the $class declared 4 # line above my $obj_class = shift @args; my $list = shift @args or die "No slot names for $obj_class"; my @list = ( ref($list) eq 'ARRAY' ) ? @$list : ($list); my $obj_def; foreach $obj_def (@list) { my $type = $obj_class; # Hmmm. We have to do this for the closure to work. I.e. using # $obj_class in the closure dosen't work. Someday I'll actually # understand scoping in Perl. [ Uh, is this true? 11/11/96 -PBS ] # DD (22.1.2002): That's because the closure keeps a 'reference' to the # unique storage area hidden behind $obj_class. Its value changes at # each iteration of the 'while' loop. On the other hand, a new $type # variable (i.e. storage area) is created at each iteration of the # loop. Hence the value stored in each $type variable is not clobeered. my ( $name, @composites ); my $new_meth = 'new'; if ( ! ref $obj_def ) { $name = $obj_def; } else { $name = $obj_def->{'slot'}; my $composites = $obj_def->{'comp_mthds'}; @composites = ref($composites) eq 'ARRAY' ? @$composites : defined $composites ? ($composites) : (); } $methods{$name} = sub { my ($self, @list) = @_; defined $self->{$name} or $self->{$name} = []; if ( scalar @list == 1 and ref( $list[0] ) eq 'ARRAY' ) { @list = @{ $list[0] }; } push @{$self->{$name}}, map { (ref $_ and UNIVERSAL::isa($_, $obj_class)) ? $_ : $type->$new_meth($_) } @list; # Use wantarray for consistency with list, which uses it for # consistency with its own doco., and the hash impl. return wantarray ? @{$self->{$name}} : $self->{$name}; }; $class->_add_list_methods(\%methods, $name); # # Deprecated in line with list, v0.95 (1.vi.00) # $methods{"ref_$name"} = sub { my ($self) = @_; $self->{$name}; }; my $meth; foreach $meth (@composites) { $methods{$meth} = sub { my ($self, @args) = @_; map { $_->$meth(@args) } $self->$name() }; } } } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 object_tie_list Functions like C, but maintains an array of referenced objects in each slot. object_tie_list => [ { slot => xxx, # or [ ... , ... ] tie_array => [ 'ArrayName', args ,...] , class => ['ObjName', constructor_args ] }, ... ] When xxx is called with one or several arguments, Each argument is: =over =item * Stored in the array if the argument is an object of the class 'ObjName'. =item * Used to create a new object of the class 'ObjName' if the argument is an array ref. The elements of the array ref are passed to the constructor *after* the default constructor arguments. =item * Discarded if any other case. A new object is created using the default constructor arguments and stored in the array. =back =cut # no support for forwarded methods (may not make sense) sub object_tie_list { my ($class, @args) = @_; my %methods; while (@args) { my $obj_tie_ref = shift @args; my $obj_class_ref = $obj_tie_ref->{class} or croak "No class passed to object_tie_list"; my $tie_array_ref = $obj_tie_ref->{tie_array} or croak "No tied array name passed to object_tie_list"; my $list = $obj_tie_ref->{slot} or croak "No slot names passef to object_tie_list"; my @slot_list = ( ref($list) eq 'ARRAY' ) ? @$list : ($list); # my $composites = $obj_tie_ref->{'comp_mthds'}; # my @composites = ref($composites) eq 'ARRAY' ? @$composites # : defined $composites ? ($composites) : (); my $obj_class = shift @$obj_class_ref; foreach my $obj_def (@slot_list) { my $new_meth = 'new'; my $name = $obj_def; # kept for closures $methods{$name} = sub { my ($self, @list) = @_; if ( ! defined $self->{$name} ) { my ($tie_class, @c_args) = @$tie_array_ref ; # second args of tie is forced into a scalar context. tie my (@array), $tie_class, @c_args; $self->{$name} = \@array; } @{$self->{$name}} = map { (ref $_ and UNIVERSAL::isa($_, $obj_class)) ? $_ : ref $_ eq 'ARRAY' ? $obj_class->$new_meth(@$_) : $obj_class->$new_meth(@$obj_class_ref) } @list if scalar @list; # Use wantarray for consistency with list, which uses it for # consistency with its own doco., and the hash impl. return wantarray ? @{$self->{$name}} : $self->{$name}; }; $class->_add_list_methods(\%methods, $name); # my $meth; # foreach $meth (@composites) { # $methods{$meth} = sub { # my ($self, @args) = @_; # map { $_->$meth(@args) } $self->$name() # }; # } } } $class->install_methods(%methods); } # ---------------------------------------------------------------------------- =head2 object_tie_hash Functions like C, but maintains an array of referenced objects in each slot. object_tie_hash => [ { slot => xxx, # or [ ... , ... ] tie_hash => [ 'HashName', args ,...] , class => ['ObjName', @constructor_args ] }, ... ] When xxx is called with more than one argument, xxx is treated as the key. If the second argument is a: =over =item * An object of the class 'ObjName' then the object is the new value of the key 'xxx'. =item * An array ref. A new object of the class 'ObjName' is created and stored in the hash. The elements of the array ref are passed to the constructor *after* the default constructor arguments. =item * Anything else: A new object is created using the default constructor arguments. =back Example, if the default constructor arguments are @c_args : xxx( # xxx[0] = $obj->isa('ObjName') ? $obj : ObjName->new(@c_args) $obj, # xxx[1] = ObjName->new(@c_args, arg => 'bar') [ arg => 'bar'], # xxx[2 to 8] = ObjName->new(@constructor_arg) 1 .. 6 ) =cut # no support for forwarded methods (may not make sense) sub object_tie_hash { my ($class, @args) = @_; my %methods; while (@args) { my $obj_tie_ref = shift @args; my $obj_class_ref = $obj_tie_ref->{class} or croak "No class passed to object_tie_hash"; my $tie_hash_ref = $obj_tie_ref->{tie_hash} or croak "No tied hash name passed to object_tie_hash"; my $hash = $obj_tie_ref->{slot} or croak "No slot names passef to object_tie_hash"; my @slot_hash = ( ref($hash) eq 'ARRAY' ) ? @$hash : ($hash); # my $composites = $obj_tie_ref->{'comp_mthds'}; # my @composites = ref($composites) eq 'ARRAY' ? @$composites # : defined $composites ? ($composites) : (); my $obj_class = shift @$obj_class_ref; foreach my $obj_def (@slot_hash) { my $new_meth = 'new'; my $name = $obj_def; # kept for closures $methods{$name} = sub { my ($self, @list) = @_; # when creating : key => [ constructor args ] , key => ... # or key => obj , key => obj ... if ( ! defined $self->{$name} ) { my ($tie_class, @c_args) = @$tie_hash_ref ; # second args of tie is forced into a scalar context. tie my (%hash), $tie_class, @c_args; $self->{$name} = \%hash; } if (scalar @list == 1) { my $key = shift @list; if (ref $key eq 'ARRAY') { return @{$self->{$name}}{@$key}; } else { return $self->{$name}->{$key}; } } else { while (1) { my $key = shift @list; defined $key or last; my $value = shift @list; defined $value or carp "No value for key $key."; $self->{$name}->{$key} = (ref $value and UNIVERSAL::isa($value, $obj_class)) ? $value : ref $value eq 'ARRAY' ? $obj_class->$new_meth(@$obj_class_ref,@$value) : $obj_class->$new_meth(@$obj_class_ref) ; } } wantarray ? %{$self->{$name}} : $self->{$name}; }; $class->_add_hash_methods(\%methods, $name) ; } } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 forward forward => [ comp => 'method1', comp2 => 'method2' ] Define pass-through methods for certain fields. The above defines that method C will be handled by component C, whilst method C will be handled by component C. =cut sub forward { my ($class, %args) = @_; my %methods; foreach (keys %args) { my $slot = $_; my @methods = @{$args{$_}}; foreach (@methods) { my $field = $_; $methods{$field} = sub { my ($self, @args) = @_; $self->$slot()->$field(@args); }; } } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 boolean boolean => [ qw / foo bar baz / ] Creates methods for setting, checking and clearing flags. All flags created with this meta-method are stored in a single vector for space efficiency. The argument to boolean should be a string or a reference to an array of strings. For each string x it defines several methods: =over 4 =item x Returns the value of the x-flag. If called with an argument, it first sets the x-flag to the truth-value of the argument. =item set_x Equivalent to x(1). =item clear_x Equivalent to x(0). =back Additionally, boolean defines three class methods: =over 4 =item bits Returns the vector containing all of the bit fields (remember however that a vector containing all 0 bits is still true). =item boolean_fields Returns a list of all the flags by name. =item bit_dump Returns a hash of the flag-name/flag-value pairs. =back =cut sub _ancestry { my $class = shift; my ($target_class) = @_; return map { $_, $class->_ancestry ($_) } @{"${target_class}::ISA"}; } sub boolean { my ($class, @args) = @_; my %methods; my $TargetClass = $class->find_target_class; my $bstore = join '__', $TargetClass, 'boolean'; my $boolean_fields = $BooleanFields{$TargetClass}; $methods{'bits'} = sub { my ($self, $new) = @_; defined $new and $self->{$bstore} = $new; $self->{$bstore}; }; $methods{'bit_fields'} = sub { @$boolean_fields; }; $methods{'bit_dump'} = sub { my ($self) = @_; map { ($_, $self->$_()) } @$boolean_fields; }; foreach (@args) { my $field = $_; my $bfp = $BooleanPos{$TargetClass}++; # $boolean_pos a global declared at top of file. We need to make # a local copy because it will be captured in the closure and if # we capture the global version the changes to it will effect all # the closures. (Note also that it's value is reset with each # call to import_into_class.) push @$boolean_fields, $field; # $boolean_fields is also declared up above. It is used to store a # list of the names of all the bit fields. $methods{$field} = sub { my ($self, $on_off) = @_; defined $self->{$bstore} or $self->{$bstore} = ""; if (defined $on_off) { vec($self->{$bstore}, $bfp, 1) = $on_off ? 1 : 0; } vec($self->{$bstore}, $bfp, 1); }; $methods{"set_$field"} = sub { my ($self) = @_; $self->$field(1); }; $methods{"clear_$field"} = sub { my ($self) = @_; $self->$field(0); }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- # Docs removed: is there any real use for struct? # XXX Candidate for a pseudo-hash? sub struct { my ($class, @args) = @_; my %methods; my $TargetClass = $class->find_target_class; my $struct_fields = $StructFields{$TargetClass}; $methods{'struct_fields'} = sub { @$struct_fields; }; $methods{'struct'} = sub { # For filling up the whole structure at once. The values must be # provided in the order they were declared. my ($self, @values) = @_; defined $self->{'struct'} or $self->{'struct'} = []; @values and @{$self->{'struct'}} = @values; @{$self->{'struct'}}; }; $methods{'struct_dump'} = sub { my ($self) = @_; map { ($_, $self->$_()) } @$struct_fields; }; foreach (@args) { my $field = $_; # $StructPos is a global declared at top of file. We need to make a # local copy because it will be captured in the closure and if we # capture the global version the changes to it will affect all the # closures. my $sfp = $StructPos{$TargetClass}++; # $struct_fields is also declared up above. It is used to store a # list of the names of all the struct fields. push @$struct_fields, $field; $methods{$field} = sub { my ($self, $new) = @_; defined $self->{'struct'} or $self->{'struct'} = []; defined $new and $self->{'struct'}->[$sfp] = $new; $self->{'struct'}->[$sfp]; }; $methods{"clear_$field"} = sub { my ($self) = @_; defined $self->{'struct'} or $self->{'struct'} = []; $self->{'struct'}->[$sfp] = undef; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 listed_attrib listed_attrib => [ qw / foo bar baz / ] Like I, I creates x, set_x, and clear_x methods. However, it also defines a class method x_objects which returns a list of the objects which presently have the x-flag set to true. N.B. listed_attrib does not use the same space efficient implementation as boolean, so boolean should be prefered unless the x_objects method is actually needed. =cut sub listed_attrib { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; my %list = (); $methods{$field} = sub { my ($self, $on_off) = @_; if (defined $on_off) { if ($on_off) { $list{$self} = $self; } else { delete $list{$self}; } } $list{$self} ? 1 : 0; }; $methods{"set_$field"} = sub { my ($self) = @_; $self->$field(1); }; $methods{"clear_$field"} = sub { my ($self) = @_; $self->$field(0); }; $methods{$field . "_objects"} = sub { values %list; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 key_attrib key_attrib => [ qw / foo bar baz / ] Creates get/set methods like get/set but also maintains a hash in which each object is stored under the value of the field when the slot is set. If an object has a slot set to a value which another object is already set to the object currently set to that value has that slot set to undef and the new object will be put into the hash under that value. (I.e. only one object can have a given key. The method find_x is defined which if called with any arguments returns a list of the objects stored under those values in the hash. Called with no arguments, it returns a reference to the hash. =cut sub key_attrib { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; my %list = (); $methods{$field} = sub { my ($self, $new) = @_; if (defined $new) { # We need to set the value if (defined $self->{$field}) { # the object must be in the hash under its old value so # that entry needs to be deleted delete $list{$self->{$field}}; } my $old; if ($old = $list{$new}) { # There's already an object stored under that value so we # need to unset it's value $old->{$field} = undef; } # Set our value to new $self->{$field} = $new; # Put ourself in the list under that value $list{$new} = $self; } $self->{$field}; }; $methods{"clear_$field"} = sub { my ($self) = @_; delete $list{$self->{$field}}; $self->{$field} = undef; }; $methods{"find_$field"} = sub { my ($self, @args) = @_; if (scalar @args) { return @list{@args}; } else { return \%list; } }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 key_with_create key_with_create => [ qw / foo bar baz / ] Just like key_attrib except the find_x method is defined to call the new method to create an object if there is no object already stored under any of the keys you give as arguments. =cut sub key_with_create { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; my %list = (); $methods{$field} = sub { my ($self, $new) = @_; if (defined $new) { # We need to set the value if (defined $self->{$field}) { # the object must be in the hash under its old value so # that entry needs to be deleted delete $list{$self->{$field}}; } my $old; if ($old = $list{$new}) { # There's already an object stored under that value so we # need to unset it's value $old->{$field} = undef; } # Set our value to new $self->{$field} = $new; # Put ourself in the list under that value $list{$new} = $self; } $self->{$field}; }; $methods{"clear_$field"} = sub { my ($self) = @_; delete $list{$self->{$field}}; $self->{$field} = undef; }; $methods{"find_$field"} = sub { my ($class, @args) = @_; if (scalar @args) { foreach (@args) { $class->new->$field($_) unless defined $list{$_}; } return @list{@args}; } else { return \%list; } }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 list Creates several methods for dealing with slots containing list data. Takes a string or a reference to an array of strings as its argument and for each string, x, creates the methods: =over 4 =item x This method returns the list of values stored in the slot. In an array context it returns them as an array and in a scalar context as a reference to the array. =item x_push =item x_pop =item x_shift =item x_unshift =item x_splice =item x_clear =item x_count Returns the number of elements in x. =item x_index Takes a list of indices, returns a list of the corresponding values. =item x_set Takes a list, treated as pairs of index => value; each given index is set to the corresponding value. No return. =back =cut sub list { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; $methods{$field} = sub { my ($self, @list) = @_; defined $self->{$field} or $self->{$field} = []; # # Push of arguments deprecated. Later, the semanticmay # change (likely to replace, rather than push onto, the list). # # XXX Deprecated 25.v.00 --------- # This code is deprecated. Use at your peril. It is not # supported, and will disappear at or after 25.v.01 push @{$self->{$field}}, map { ref $_ eq 'ARRAY' ? @$_ : ($_) } @list; # XXX Deprecated 25.v.00 --------- return wantarray ? @{$self->{$field}} : $self->{$field}; }; $class->_add_list_methods(\%methods, $field); # # Deprecated. v0.95 1.vi.00 # $methods{"${field}_ref"} = sub { my ($self) = @_; $self->{$field}; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- # added by Dominique Dumont (22.i.02) =head2 tie_list Much like list, but can use a tied list instead. Takes a list of pairs, where the first is the name of the component, the second is an array reference. The array reference takes the usual tie parameters. For instance if Array_A and ArrayB are tied arrays, you can have: tie_list => [ foo => [ 'Array_A', foo => 'x', bar => 'B' ], baz => [ 'ArrayB', baz => 0] ], =cut sub tie_list { my ($class, @args) = @_; my %methods; while ( my ($fieldr, $tie_args) = splice (@args, 0, 2)) { my $field; my ($tie_class,@c_args)= @$tie_args ; foreach $field (ref $fieldr ? @$fieldr : $fieldr) { $methods{$field} = sub { my $self = shift; my @list = @_; if ( ! defined $self->{$field} ) { # second args of tie is forced into a scalar context. tie my (@array), $tie_class, @c_args; $self->{$field} = \@array; } @{$self->{$field}} = @_ if scalar @_ ; return wantarray ? @{$self->{$field}} : $self->{$field}; }; $class->_add_list_methods(\%methods, $field); } $class->install_methods(%methods); } } # ------------------------------------- # added by Dominique Dumont (22.i.02) sub _add_list_methods { my ($class,$methods, $field) = @_; $methods->{"${field}_pop"} = $methods->{"pop_$field"} = sub { my ($self) = @_; pop @{$self->{$field}} }; $methods->{"${field}_push"} = $methods->{"push_$field"} = sub { my ($self, @values) = @_; push @{$self->{$field}}, @values; }; $methods->{"${field}_shift"} = $methods->{"shift_$field"} = sub { my ($self) = @_; shift @{$self->{$field}} }; $methods->{"${field}_unshift"} = $methods->{"unshift_$field"} = sub { my ($self, @values) = @_; unshift @{$self->{$field}}, @values; }; $methods->{"${field}_splice"} = $methods->{"splice_$field"} = sub { my ($self, $offset, $len, @list) = @_; splice(@{$self->{$field}}, $offset, $len, @list); }; $methods->{"${field}_clear"} = $methods->{"clear_$field"} = sub { my ($self) = @_; # this code may clobbed references passed by the user # $self->{$field} = []; @{$self->{$field}} = () ; }; $methods->{"${field}_count"} = $methods->{"count_$field"} = sub { my ($self) = @_; return exists $self->{$field} ? scalar @{$self->{$field}} : 0; }; $methods->{"${field}_index"} = $methods->{"index_$field"} = sub { my $self = shift; my (@indices) = @_; my @Result; push @Result, $self->{$field}->[$_] for @indices; return $Result[0] if @_ == 1; return wantarray ? @Result : \@Result; }; foreach my $method_name (("${field}_set" ,"set_$field")) { $methods->{$method_name} = sub { my $self = shift; my @args = @_; croak "$method_name expects an even number of fields\n" if @args % 2; while ( my ($index, $value) = splice @args, 0, 2 ) { $self->{$field}->[$index] = $value; } return @_ / 2; # required for object_list }; } } # ---------------------------------------------------------------------- =head2 hash Creates a group of methods for dealing with hash data stored in a slot. Takes a string or a reference to an array of strings and for each string, x, creates: =over 4 =item x Called with no arguments returns the hash stored in the slot, as a hash in a list context or as a reference in a scalar context. Called with one simple scalar argument it treats the argument as a key and returns the value stored under that key. Called with one array (list) reference argument, the array elements are considered to be be keys of the hash. x returns the list of values stored under those keys (also known as a I.) Called with one hash reference argument, the keys and values of the hash are added to the hash. Called with more than one argument, treats them as a series of key/value pairs and adds them to the hash. =item x_keys Returns the keys of the hash. =item x_values Returns the list of values. =item x_tally Takes a list of arguments and for each scalar in the list increments the value stored in the hash and returns a list of the current (after the increment) values. =item x_exists Takes a single key, returns whether that key exists in the hash. =item x_delete Takes a list, deletes each key from the hash. =item x_clear Resets hash to empty. =back =cut sub hash { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; $methods{$field} = sub { my ($self, @list) = @_; defined $self->{$field} or $self->{$field} = {}; if (scalar @list == 1) { my ($key) = @list; if ( my $type = ref $key ) { if ( $type eq 'ARRAY' ) { return @{$self->{$field}}{@$key}; } elsif ( $type eq 'HASH' ) { while (my ($subkey, $value) = each %$key ) { if ( $^W ) { defined $value or carp "No value for key $subkey of hash $field."; } $self->{$field}->{$subkey} = $value; } return wantarray ? %{$self->{$field}} : $self->{$field}; } else { cluck "Not a recognized ref type for hash method: $type."; } } else { # $key is simple scalar return $self->{$field}->{$key}; } } else { while (1) { my $key = shift @list; defined $key or last; my $value = shift @list; defined $value or carp "No value for key $key."; $self->{$field}->{$key} = $value; } return wantarray ? %{$self->{$field}} : $self->{$field}; } }; $class->_add_hash_methods(\%methods, $field) ; $methods{$field . "_clear"} = sub { my $self = shift; $self->{$field} = {}; }; } $class->install_methods(%methods); } # ------------------------------------- # added by Dominique Dumont (22.i.02) sub _add_hash_methods { my ($class,$methods, $field) = @_ ; $methods->{$field . "_keys"} = sub { my ($self) = @_; keys %{$self->{$field}}; }; $methods->{$field . "_values"} = sub { my ($self) = @_; values %{$self->{$field}}; }; $methods->{$field . "_exists"} = sub { my ($self) = shift; my ($key) = @_; return exists $self->{$field} && exists $self->{$field}->{$key}; }; $methods->{$field . "_tally"} = sub { my ($self, @list) = @_; defined $self->{$field} or $self->{$field} = {}; map { ++$self->{$field}->{$_} } @list; }; $methods->{$field . "_delete"} = sub { my ($self, @keys) = @_; delete @{$self->{$field}}{@keys}; }; } # ---------------------------------------------------------------------- =head2 hash_of_lists Creates a group of methods for dealing with list data stored by key in a slot. Takes a string or a reference to an array of strings and for each string, x, creates: =over 4 =item x Returns all the values for all the given keys, in order. If no keys are given, returns all the values (in an unspecified key order). The result is returned as an arrayref in scalar context. This arrayref is I part of the data structure; messing with it will not affect the contents directly (even if a single key was provided as argument.) If any argument is provided which is an arrayref, then the members of that array are used as keys. Thus, the trivial empty-key case may be utilized with an argument of []. =item x_keys Returns the keys of the hash. As an arrayref in scalar context. =item x_exists Takes a list of keys, and returns whether each key exists in the hash (i.e., the C of whether the individual keys exist). =item x_delete Takes a list, deletes each key from the hash. =item x_push Takes a key, and some values. Pushes the values onto the list denoted by the key. If the first argument is an arrayref, then each element of that arrayref is treated as a key and the elements pushed onto each appropriate list. =item x_pop Takes a list of keys, and pops each one. Returns the list of popped elements. undef is returned in the list for each key that is has an empty list. =item x_last Like C, but does not actually change any of the lists. =item x_unshift Like push, only the from the other end of the lists. =item x_shift Like pop, only the from the other end of the lists. =item x_splice Takes a key, offset, length, and a values list. Splices the list named by the key. Anything from the offset argument (inclusive) may be omitted. See L. =item x_set Takes a key, and a set of index->value pairs, and sets each specified index to the corresponding value for the given key. =item x_clear Takes a list of keys. Resets each named list to empty (but does not delete the keys.) =item x_count Takes a list of keys. Returns the sum of the number of elements for each named list. =item x_index Takes a key, and a list of indices. Returns a list of each item at the corresponding index in the list of the given key. Uses undef for indices beyond range. =item x_remove Takes a key, and a list of indices. Removes each corresponding item from the named list. The indices are effectively looked up at the point of call --- thus removing indices 3, 1 from list (a, b, c, d) will remove (d) and (b). =item x_sift Takes a key, and a set of named arguments, which may be a list or a hash ref. Removes list members based on a grep-like approach. =over 4 =item filter The filter function used (as a coderef). Is passed two arguments, the value compared against, and the value in the list that is potential for grepping out. If returns true, the value is removed. Default: sub { $_[0] == $_[1] } =item keys The list keys to sift through (as an arrayref). Unknown keys are ignored. Default: all the known keys. =item values The values to sift out (as an arrayref). Default: C<[undef]> =back =back Options: =over 4 =item -static Make the corresponding storage class-specific, rather than instance-specific. =back =cut sub hash_of_lists { my ($class, @args) = @_; my $static = 0; foreach (@args) { if ( substr ($_, 0, 1) eq '-' ) { my $option = substr $_, 1; if ( $option eq 'static' ) { $static = 1; } else { croak "Unrecognized option to hash_of_lists: $option\n"; } } else { my %methods; my $field = $_; $methods{$field} = q{sub { my $self = shift; my @list = @_; my @Result; if ( @list ) { if ( @list == 1 and ref ($list[0]) eq 'ARRAY' ) { @Result = map @$_, @{__STORAGE__}{@{$list[0]}}; } else { my @keys = map ref ($_) eq 'ARRAY' ? @$_: $_, grep exists __STORAGE__->{$_}, @list; @Result = map @$_, @{__STORAGE__}{@keys}; } } else { @Result = map @$_, values %{__STORAGE__}; } return wantarray ? @Result : \@Result; }}; $methods{$field . "_keys"} = q{sub { my ($self) = shift; my @Result = keys %{__STORAGE__}; return wantarray ? @Result : \@Result; }}; $methods{$field . "_exists"} = q{sub { my ($self) = shift; my (@keys) = @_; my $found = 1; for (@keys) { $found &&= exists __STORAGE__->{$_}; } return $found; }}; $methods{$field . "_delete"} = q{sub { my ($self, @keys) = @_; delete @{__STORAGE__}{@keys}; }}; $methods{$field . "_push"} = q{sub { my ($self, $key, @values) = @_; my @keys = ref ($key) eq 'ARRAY' ? @$key : $key; for (@keys) { push @{__STORAGE__->{$_}}, @values; } }}; $methods{$field . "_unshift"} = q{sub { my ($self, $key, @values) = @_; my @keys = ref ($key) eq 'ARRAY' ? @$key : $key; for (@keys) { unshift @{__STORAGE__->{$_}}, @values; } }}; $methods{$field . "_pop"} = q{sub { my ($self, @keys) = @_; my @old; for (@keys) { push @old, pop @{__STORAGE__->{$_}}; } return @old; }}; $methods{$field . "_last"} = q{sub { my ($self, @keys) = @_; my @old; for (@keys) { push @old, __STORAGE__->{$_}->[-1]; } return @old; }}; $methods{$field . "_shift"} = q{sub { my ($self, @keys) = @_; my @old; for (@keys) { push @old, shift @{__STORAGE__->{$_}}; } return @old; }}; $methods{$field . "_splice"} = q{sub { my ($self, $key, $offset, $length, @values) = @_; splice @{__STORAGE__->{$key}}, $offset, $length, @values; }}; my $method_name = "${field}_set"; $methods{$method_name} = q{sub{ my $self = shift; croak "__METHOD_NAME__ expects a key and then index => " . "value pairs.\n" unless @_ % 2; my ($key, @args) = @_; while ( my ($index, $value) = splice @args, 0, 2 ) { __STORAGE__->{$key}->[$index] = $value; } return; }}; $methods{$method_name} =~ s!__METHOD_NAME__!$method_name!gs; $methods{$field . "_clear"} = q{sub { my ($self, @keys) = @_; for (@keys) { __STORAGE__->{$_} = []; } }}; $methods{$field . "_count"} = q{sub { my ($self, @keys) = @_; my $Result = 0; # Avoid autovivifying additional entries. for (@keys) { $Result += exists __STORAGE__->{$_} ? scalar @{__STORAGE__->{$_}} : 0; } return $Result; }}; $methods{"${field}_index"} = q{sub { my ($self, $key_r, @indices) = @_; my (@Result, $index, $key); my @keys = ref ($key_r) eq 'ARRAY' ? @$key_r : $key_r; foreach $key (@keys) { my $ary = __STORAGE__->{$key}; foreach $index (@indices) { push @Result, ( @{$ary} > $index ) ? $ary->[$index] : undef; } } return wantarray ? @Result : \@Result; }}; $methods{"${field}_remove"} = q{sub { my ($self, $key_r, @indices) = @_; my ($index, $key); my @keys = ref ($key_r) eq 'ARRAY' ? @$key_r : $key_r; foreach $key (@keys) { my $ary = __STORAGE__->{$key}; foreach $index (sort {$b<=>$a} grep $_ < @$ary, @indices) { splice (@$ary, $index, 1); } } return; }}; $methods{"${field}_sift"} = q{sub { my $self = shift; my %args; if ( @_ == 1 and ref $_[0] eq 'HASH' ) { %args = %{$_[0]}; } else { %args = @_; } my $filter_sr = $args{'filter'} || sub { $_[0] == $_[1] }; my $keys_ar = $args{'keys'} || [ keys %{__STORAGE__} ]; my $values_ar = $args{'values'} || [undef]; # This is harder than it looks; reverse means we want to grep out only # if *none* of the values matches. I guess an evaled block, or closure # or somesuch is called for. # my $reverse = $args{'reverse'} || 0; my ($key, $i, $value); KEY: foreach $key (@$keys_ar) { next KEY unless exists __STORAGE__->{$key}; INDEX: for ($i = $#{__STORAGE__->{$key}}; $i >= 0; $i--) { foreach $value (@$values_ar) { if ( $filter_sr->($value, __STORAGE__->{$key}[$i]) ) { splice @{__STORAGE__->{$key}}, $i, 1; next INDEX; } } } } }}; my $replace = $static ? '$store' : "\$self->{$field}"; foreach (@methods{keys %methods}) { s!__STORAGE__!$replace!gm unless ref $_; ; } if ( $static ) { my $store; for (@methods{keys %methods}) { $code = eval $_; croak "Compilation of \n$_\n failed: $@\n" if $@; croak "Compilation of \n$_\n did not return a coderef: $code\n" unless ref $code eq 'CODE'; $_ = $code; } } $class->install_methods (%methods); } } } # ---------------------------------------------------------------------------- =head2 tie_scalar Create a get/set method to deal with the tied scalar. Takes a list of pairs, where the first is the name of the component, the second is an array reference. The array reference takes the usual tie parameters. For instance if Enum and Boolean are tied scalar that accept default values, you can have: tie_scalar => [ foo => [ 'Enum', enum => [qw/A B C/], default => 'B' ], bar => [ 'Enum', enum => [qw/T0 T1/], default => 'T1'], baz => ['Boolean', default => 0] ], =cut # added by Dominique Dumont (22.i.02) sub tie_scalar { my ($class, @args) = @_; my %methods; while ( my ($fieldr, $tie_args) = splice (@args, 0, 2)) { my $field; my ($class,@c_args)= @$tie_args ; foreach $field (ref $fieldr ? @$fieldr : $fieldr) { $methods{$field} = sub { my ($self, $value) = @_; if ( ! defined $self->{$field} ) { my $scalar; # second args of tie is forced into a scalar context. tie ($scalar, $class, @c_args); $self->{$field} = \$scalar; } my $ref = $self->{$field} ; $$ref=$value if defined $value; return $$ref ; }; } } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 tie_hash Much like C, but uses a tied hash instead. Takes a list of pairs, where the first is the name of the component, the second is a hash reference. The hash reference recognizes the following keys: =over 4 =item tie I. The name of the class to tie to. Id the required class>. =item args I. Additional arguments for the tie, as an array ref. =back The first argument can also be an arrayref, specifying multiple components to create. Example: tie_hash => [ hits => { tie => qw/ Tie::RefHash /, args => [], }, ], =cut sub tie_hash { my ($class, @args) = @_; my %methods; while ( my ($fieldr, $args) = splice (@args, 0, 2)) { my $field; foreach $field (ref $fieldr ? @$fieldr : $fieldr) { $methods{$field} = sub { my ($self, @list) = @_; if ( ! defined $self->{$field} ) { my %hash; tie %hash, $args->{'tie'}, @{$args->{'args'}}; $self->{$field} = \%hash; } if (scalar @list == 1) { my $key = shift @list; if (ref $key eq 'ARRAY') { return @{$self->{$field}}{@$key}; } else { return $self->{$field}->{$key}; } } else { while (1) { my $key = shift @list; defined $key or last; my $value = shift @list; defined $value or carp "No value for key $key."; $self->{$field}->{$key} = $value; } wantarray ? %{$self->{$field}} : $self->{$field}; } }; $class->_add_hash_methods(\%methods, $field); } } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 static_hash Much like C, but uses a class-based hash instead. =cut sub static_hash { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; my %hash; $methods{$field} = sub { my ($class, @list) = @_; if (scalar @list == 1) { my ($key) = @list; if ( my $type = ref $key ) { if ( $type eq 'ARRAY' ) { return @hash{@$key}; } elsif ( $type eq 'HASH' ) { while ( my ($subkey, $value) = each %$key ) { if ( $^W ) { defined $value or carp "No value for key $subkey of hash $field."; } $hash{$subkey} = $value; } return wantarray ? %hash : \%hash; } else { cluck "Not a recognized ref type for static hash: $type."; } } else { return $hash{$key}; } } else { while (1) { my $key = shift @list; defined $key or last; my $value = shift @list; defined $value or carp "No value for key $key."; $hash{$key} = $value; } wantarray ? %hash : \%hash; } }; $methods{$field . "_keys"} = sub { my ($class) = @_; keys %hash; }; $methods{$field . "_values"} = sub { my ($class) = @_; values %hash; }; $methods{$field . "_exists"} = sub { my ($class) = shift; my ($key) = @_; return exists $hash{$key}; }; $methods{$field . "_tally"} = sub { my ($class, @list) = @_; map { ++$hash{$_} } @list; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 code code => [ qw / foo bar baz / ] Creates a slot that holds a code reference. Takes a string or a reference to a list of string and for each string, x, creates a method B which if called with one argument which is a CODE reference, it installs that code in the slot. Otherwise it runs the code stored in the slot with whatever arguments (including none) were passed in. =cut sub code { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; $methods{$field} = sub { my ($self, @args) = @_; if (ref($args[0]) eq 'CODE') { # Set the function $self->{$field} = $args[0]; } else { # Run the function on the given arguments &{$self->{$field}}(@args) } }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 method method => [ qw / foo bar baz / ] Just like B, except the code is called like a method, with $self as its first argument. Basically, you are creating a method which can be different for each object. Which is sort of weird. But perhaps useful. =cut sub method { my ($class, @args) = @_; my %methods; foreach (@args) { my $field = $_; $methods{$field} = sub { my ($self, @args) = @_; if (ref($args[0]) eq 'CODE') { # Set the function $self->{$field} = $args[0]; } else { # Run the function on the given arguments &{$self->{$field}}($self, @args) } }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head2 abstract abstract => [ qw / foo bar baz / ] This creates a number of methods will die if called. This is intended to support the use of abstract methods, that must be overidden in a useful subclass. =cut sub abstract { my ($class, @args) = @_; my %methods; my $TargetClass = $class->find_target_class; foreach (@args) { my $field = $_; $methods{$field} = sub { my ($self) = @_; my $calling_class = ref $self; die qq#Can't locate abstract method "$field" declared in #. qq#"$TargetClass", called from "$calling_class".\n#; }; } $class->install_methods(%methods); } # ---------------------------------- =head2 counter Create components containing simple counters that may be read, incremented, or reset. For value x, the methods are: =over 4 =item x (accepts argument to set), =item x_incr (accepts argument for increment size), =item x_reset The counter is implicitly initialized to zero. =back =cut sub counter { my $class = shift; my (@names) = @_; my %methods; my $name; foreach $name (@names) { $methods{$name} = sub { my $self = shift; $self->{$name} = $_[0] if @_; $self->{$name} = 0 unless exists $self->{$name}; return $self->{$name}; }; $methods{"${name}_incr"} = sub { my $self = shift; $self->{$name} = 0 unless exists $self->{$name}; $self->{$name} += @_ ? $_[0] : 1; }; $methods{"${name}_reset"} = sub { my $self = shift; $self->{$name} = 0; } } $class->install_methods (%methods); } # ---------------------------------------------------------------------- =head2 EXPERIMENTAL: copy Produce a copy of self. The copy is a *shallow* copy; any references will be shared by the instance upon which the method is called and the returned newborn. =cut sub copy { my ($class, @args) = @_; my %methods; foreach (@args) { my $name = $_; $methods{$name} = sub { my $self = shift; my $class = ref $self; return bless { %$self }, $class; }; } $class->install_methods(%methods); } # ---------------------------------------------------------------------- =head1 ADDDING NEW METHOD TYPES MethodMaker is a class that can be inherited. A subclass can define new method types by writing a method that generates a hash of method_name/code-reference pairs, and then calls the class method C on them. If the coderef is in fact a string, then that string will be Cled in the hope of getting a coderef to use. For example a simple sub-class that defines a method type upper_case_get_set might look like this: package Class::MethodMakerSubclass; use strict; use base qw( Class::MethodMaker ); sub upper_case_get_set { my $class = shift; my ($name) = @_; my %methods; $methods{$name} = sub { my ($self, $new) = @_; defined $new and $self->{$name} = uc $new; $self->{$name}; }; $class->install_methods (%methods); } 1; Alternatively, rather than a coderef, the values of the hash passed to install_methods may be strings, which will be evaled in the hope of returning a coderef to use. If the eval fails, or anything other than a coderef is returned, then C::MM croaks. Any return value from a method (above) that is used to generate methods will be passed to install_methods --- so in the above, the line $class->install_methods (%methods); could be replaced with return %methods =cut ## EXPERIMENTAL META-METHODS =head2 EXPERIMENTAL: builtin_class History: This method was in 0.92, undocumented. Does anybody use this? Would anybody use this subject to some enhancement or other? Let me know. Purpose: This class generates a wrapper around some builtin function, cacheing the results in the object and providing a by-name interface. Takes a (core) function name, and a arrayref of return position names (we will call it pos_list). Creates: =over 4 =item new Calls the core func with any given arguments, stores the result in the instance. =item x For each member of pos_list, creates a method of the same name which gets/sets the nth member of the returned list, where n is the position of x in pos_list. =item fields Returns pos_list, in the given order. =item dump Returns a list item name, item value, in order. =back Example Usage: package Stat; use Class::MethodMaker builtin_class => [stat => [qw/ dev ino mode nlink /]], package main; my $file = "$ENV{HOME}/.profile"; my $s = Stat->new ($file); print "File $file has ", $s->nlink, " links\n"; Note that (a) the new method does not check the return value of the function called (in the above example, if $file does not exist, you will silently get an empty object), and (b) if you really want the above example, see the core File::stat module. But you get the idea, I hope. =cut sub builtin_class { my ($class, $func, $arg) = @_; my @list = @$arg; my %results = (); my $field; my $TargetClass = $class->find_target_class; my $struct_fields = $StructFields{$TargetClass}; # Cuz neither \&{"CORE::$func"} or $CORE::{$func} work ... N.B. this # only works for core functions that take only one arg. But I can't # quite figure out how to pass in the list without it getting evaluated # in a scalar context. Hmmm. my $corefunc = eval "sub { scalar \@_ ? CORE::$func(shift) : CORE::$func }"; $results{'new'} = sub { my ($class, @args) = @_; my $self = []; @$self = &$corefunc(@args); bless $self, $class; }; $results{'fields'} = sub { @$struct_fields; }; $results{'dump'} = sub { my ($self) = @_; map { ($_, $self->$_()) } @$struct_fields; }; foreach $field (@list) { my $sfp = $StructPos{$TargetClass}++; # $struct_pos a global declared at top of file. We need to make # a local copy because it will be captured in the closure and if # we capture the global version the changes to it will effect all # the closures. (Note also that its value is reset with each # call to import_into_class.) push @$struct_fields, $field; # $struct_fields is also declared up above. It is used to store a # list of the names of all the struct fields. $results{$field} = sub { my $self = shift; $self->[$sfp] = $_[0] if @_; $self->[$sfp]; }; } $class->install_methods(%results); } =head1 EXAMPLES Z<> =head1 BUGS Z<> =head1 REPORTING BUGS Email the author. =head1 AUTHOR Current Maintainer: Martyn J. Pearce fluffy@cpan.org Original Author: Peter Seibel (Organic Online) Contributions from: Dominique Dumont (Dominique_Dumont@hp.com) Hewlett-Packard Company. http://www.hp.com Evolution Online Systems, Inc. http://www.evolution.com Matthew Persico Yitzchak Scott-Thoennes =head1 COPYRIGHT Copyright (c) 2002, 2001, 2000 Martyn J. Pearce. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. Copyright 1998, 1999, 2000 Evolution Online Systems, Inc. You may use this software for free under the terms of the MIT License. More info posted at http://www.evolution.com, or contact info@evolution.com Copyright (c) 1996 Organic Online. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. =head1 SEE ALSO C, C, "Object-Oriented Perl" by Damian Conway. =cut