NAME

ContractClosure - An alternative implementation av Sub::Contract, using closures instead of dynamic compilation

SYNOPSIS

to control arguments passed in array style, and cache the results:

            

              
              
use ContractClosure;
contract('foo',
  in => { # define constraints on input arguments
   count => 3,           # there must be exactly 3 input arguments
   defined => 1,         # they must all be defined
   check => [ undef,                              # no constraint on first argument
       \&is_integer,                       # argument ok if is_integer(<arg>) returns true
       sub { return (ref $_[0] eq ""); },  # ok if argument is a scalar
     ],
  },
  out => { # define constraints on output arguments
    count => 2,
  },
  cache => { size => 10000 },
 );
sub foo {
    my($a,$b,$c) = @_;
    return (1,undef);
}
            
          

and to control arguments passed in hash style:

            

              
              
contract('foo',
  in => { count => 4,     # must be 4 input arguments
            # do not need to be all defined ('defined => 0' is the default)
   check => { bib => \&is_year,      # if key 'bib' exists, its value must pass is_year()
       bob => \&is_shortdate, # if key 'bob' exists, its value must pass is_shortdate()
       bub => undef,          # no constraint on bub except that this key must exist (but can be 'undef')
     },
   optional => ['bib']               # allow key 'bib' to be non existing (but if it exists, it must pass 'is_year')
 },
  out => { count => 1,
    defined => 1,
  },
 );
sub foo {
    my(%hash) = @_;
    print "arg1: ".$hash{bib};
    print "arg2: ".$hash{bob};
    return $b;
}