=head1 TITLE

library/objecthacks.imc - This library provides some class and object helper functions.
It is intended as a temporary workaround for some missing features and will be removed
soon.

=head1 SYNOPSIS

=over 4

=item __new_class( "Foo" )

Creates a new class C<Foo> and calls C<_Foo::__register> if it exists.
It then adds C<_Foo::__init> as the constructor if the sub is found.

=item __new_class( "Foo", "Bar" )

Same as above, but creates Foo as a subclass of Bar.

=item __add_method( "Foo", "bar" )

Searches the sub C<_Foo::bar> and stores it as "bar" in namespace "Foo".

=item __add_method( "Baz", "asString", "__get_string" )

Searches the sub '_Baz::asString' and stores it as 'asString' and '__get_string' in namespace 'Baz'.

=back

=head1 FUNCTIONS

=over 4

=item class = __new_class( name, base )

Creates a new class, calls it's __register sub and adds it's __init method as constructor.

=over 4

=item parameter C<name>

The name of the class to create.

=item parameter C<base> B<(PMC|string;optional)>

The (name of the) base class of the class to create.

=back

Returns the created ParrotClass object.

=cut

.sub __new_class
    .param string name
    .param string basename
    .param pmc basepmc
    .param int twice_ok
    .local pmc ret
    .local pmc temp

    find_type I0, name
    if I0 == 0 goto NAME_OK
    if twice_ok goto END
    print " *\n * fatal error: a class with the name '"
    print name
    print "' is already registered!\n *\n\n"
    sleep 1
    branch END
NAME_OK:
    
    # baseclass specified?
    if I2 == 2 goto SUBCLASS1
    if I3 == 1 goto SUBCLASS2

    newclass ret, name
    branch INIT
    
SUBCLASS1:
    subclass ret, basename, name
    branch INIT
    
SUBCLASS2:
    subclass ret, basepmc, name
    
INIT:
    temp = __lookup_method( name, "__init", 1 )
    isnull temp, REGISTER
    __add_method( name, "__init", temp )
    
REGISTER:
    temp = __lookup_method( name, "__register", 1 )
    isnull temp, END
    .pcc_begin prototyped
	.pcc_call temp
    .pcc_end
    
END:
    .pcc_begin_return
    .return ret
    .pcc_end_return
.end


=item __add_method( class, method, store_as )

Adds a method to a class namespace.

=over 4

=item parameter C<class> B<(string)>

The name of the class to which the method should be added.

=item parameter C<method> B<(string)>

The name of the method to add.

=item parameter C<store_as> B<(string, optional)>

Also store the method under this name.

=back

This function returns nothing.


=cut

.sub __add_method
    .param string class
    .param string method
    .param string store
    .param pmc sub2
    .local pmc sub
    .local int argc
    
    argc = I2
    sub = sub2
    if I3 == 1 goto SKIP_SUB
    sub = __lookup_method( class, method )
SKIP_SUB:

    # store it as the method sub
    store_global class, method, sub
    if argc < 3 goto END
    store_global class, store, sub
END:
    .pcc_begin_return
    .pcc_end_return
.end

=item (retvals) = __call( obj, methodname, ... )

Calls the specified method of an object.

=over 4

=item parameter C<obj> B<(PMC)>

The object.

=item parameter C<method> B<(string)>

Call this method on the specified object.

=back

This function returns the result of the called method.

=cut

.sub __call
    set S0, S5
    set P2, P5
    
    set S5, S6
    set S6, S7
    set S7, S8
    set S8, S9
    set S9, S10
    set S10, S11
    set S11, S12
    set S12, S13
    set S13, S14
    set S14, S15
    set S15, S16
    set S16, S17
    set S17, S18
    set S18, S19
    set S19, S20
    set S20, S21
    set S21, S22
    set S22, S23
    set S23, S24
    set S24, S25
    set S25, S26
    set S26, S27
    set S27, S28
    set S28, S29
    set S29, S30
    set S30, S31
    null S31

    set P5, P6
    set P6, P7
    set P7, P8
    set P8, P9
    set P9, P10
    set P10, P11
    set P11, P12
    set P12, P13
    set P13, P14
    set P14, P15
    set P15, P16
    set P16, P17
    set P17, P18
    set P18, P19
    set P19, P20
    set P20, P21
    set P21, P22
    set P22, P23
    set P23, P24
    set P24, P25
    set P25, P26
    set P26, P27
    set P27, P28
    set P28, P29
    set P29, P30
    set P30, P31

    callmethod
.end

=item method = __lookup_method( class, method, nonfatal ) B<(internal)>

Locates a method's sub PMC.

=over 4

=item parameter C<class> B<(string)>

The name of the class.

=item parameter C<method> B<(string)>

The method name.

=item parameter C<nonfatal> B<(integer,optional)>

If set to 1, C<__lookup_method> just returns a null PMC
if a method was not found. Otherwise it will
report an error and wait two seconds before continuing.

=back

Returns the method sub for the specified method of the given class.

=cut

.sub __lookup_method
    .param string class
    .param string method
    .local string tmp
    .local pmc ptmp
    .local pmc sub
    .local int nonfatal
    
    nonfatal = 0
    if I1 != 1 goto SKIP
    nonfatal = I5
SKIP:

    # construct the class'es method name
    set tmp, "_"
    concat tmp, class
    concat tmp, "::"
    concat tmp, method

    # find the sub
    errorsoff 1
    find_global sub, tmp
    errorson 1
    
    # check the type
    typeof I0, sub
    if I0 != .PerlUndef goto END

ERROR:
    null sub
    if nonfatal goto END
    print " *\n * fatal error in __lookup_method: class '"
    print class
    print "' has no method '"
    print method
    print "'\n *\n\n"
    sleep 2
END:
    .pcc_begin_return
    .return sub
    .return tmp
    .pcc_end_return
.end

=back

=head1 AUTHOR

Jens Rieks E<lt>parrot at jensbeimsurfen dot deE<gt> is the author
and maintainer.
Please send patches and suggestions to the Perl 6 Internals mailing list.

=head1 COPYRIGHT

Copyright (c) 2004, the Perl Foundation.

=cut