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stefp's scratchpad

by stefp (Vicar)
on Jun 04, 2004 at 18:04 UTC ( #361034=scratchpad: print w/replies, xml ) Need Help??

=head1 NAME Class::Tidy -- class members easy access, hiding @_, autoprototyping =head1 SYNOPSIS use Class::Tidy; meth mymethod( $a \@b ; $c ) { .val = $a; .meth(@b); .&funval(); } sub mysub ( $a ) { } translates into sub mymethod($\@;$) { my ( $self, $a, $b, $c ) = @_; $self->{a} = $a; $self->meth( @b ); $self->{funval}->(); sub mysub($) { my ( $a ) = @_; =head1 DESCRIPTION =head2 classmembers easy access C++ uses struct to implement class objects. The closest Perl relative +is hash based classes. The values associated to keys are data member. Syntax to access these data members is ugly. Class::Tidy makes hash based classes less tedious to use by defining a simpler syntax for accessing the hash values, there is no runtime overhead. Compare with many Perl packages like Class::Struct or Class::Accessor provide accessors and mutators. Perl is interpreted and provides no inlining mechanism so shemes that provides accessor fo +r accessing hash/member values has high overhead. =head2 hiding @_, autoprototyping Defining subroutines in perl with prototype is somewhat reminiscent of K&R C . There is a double take to fully define a parameters: In perl sub mymethod($\@;$) { # first take: prototypes my ( $self, $a, $b, $c ) = @_; # second take: affectation from @_ In K&R C double inner(v1, v2, n) /* first take: name the parameters */ double v1[], v2[]; /* second take: define them */ { ... } (from the C manual, http://www.cs.bell-labs.com/who/dmr/cman.ps, comments are mine) the keyword meth is introducted to indicate a method meth mymethod( $a \@b ; $c ) { sub mymethod($\@;$) { my ( $self, $a, $b, $c ) = @_; =head1 SOON IN A CPAN NEAR YOU encapsulation. Need a way to declare class data members, their types and who can access the members and how Type control will be made at compile time when possible and run-time in debug mode .@a = fun(); # means expect a reference to array (run time check) .@a = [ ]; # ditto (compile time check) @.a # dereference as an array =cut # package Class::Tidy; # use Filter::Simple; $_=<<'EOF'; # test case use Class::Tidy; meth mymethod( $a \@b ; $c ) { .val = $a; .meth(@b); .&funval(); } sub mysub ( $a ) { } EOF my $subnmqr = qr|\w+(?:::\w+)?|; # to support my dirty style of "drop- +in methods" sub trans { s/ \s\.(\w+)\( /\$self->$1(/gxs; s/ \s\.(\w+) /\$self->{$1}/gxs; s/ \s.\&(\w+)\( /&{\$self->{$1}}(/gxs; s/ meth\s+($subnmqr)\s*\((.*?)\)\s*\{ / sub $1( \$self $2 ) { /sgx; s# sub\s+($subnmqr)\s*\((.*?)\)\s*{ # my ($subnm, $paras) = ($1, $2); my ($mandparas, $optparas ) = split ';', $paras; $mandparas =~ s/\s*(.*?)\s*/$1/; $optparas =~ s/\s*(.*?)\s*/$1/; my @mandpara = map { [ split /\b/, $_ ] } split /\s*,\s*|\s+/ +, $mandparas; my @optpara = map { [ split /\b/, $_ ] } split /\s*,\s*|\s+/ +, $optparas; my $proto = join '', ( map { $_->[0] } @mandpara ), ';', map { $ +_->[0] } @optpara; my $vars = join ', ', map { ( length( $_->[0] ) == 2 ? '$' : $_- +>[0] ) . $_->[1] } @mandpara, @optpara; "sub $subnm($proto) { my ($vars) = \@_; " #egxs; } &trans; # translate and print print;
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