X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2Foverload.pm;h=21a4b671ffc1cefbc0a29b182acf7e6a55b2dca0;hb=36902e12d2b30e9370acddd3ddab927d842061cf;hp=2b0b99d3cdea79228bb6633fbf6d26092bea172d;hpb=1554e226caad86d8d9b68656b257a3e2cc55803c;p=p5sagit%2Fp5-mst-13.2.git diff --git a/lib/overload.pm b/lib/overload.pm index 2b0b99d..21a4b67 100644 --- a/lib/overload.pm +++ b/lib/overload.pm @@ -1,5 +1,7 @@ package overload; +our $VERSION = '1.00'; + $overload::hint_bits = 0x20000; sub nil {} @@ -121,7 +123,7 @@ sub mycan { # Real can would leave stubs. binary => "& | ^", unary => "neg ! ~", mutators => '++ --', - func => "atan2 cos sin exp abs log sqrt", + func => "atan2 cos sin exp abs log sqrt int", conversion => 'bool "" 0+', iterators => '<>', dereferencing => '${} @{} %{} &{} *{}', @@ -368,11 +370,16 @@ postfix form. =item * I - "atan2", "cos", "sin", "exp", "abs", "log", "sqrt", + "atan2", "cos", "sin", "exp", "abs", "log", "sqrt", "int" If C is unavailable, it can be autogenerated using methods for "E" or "E=E" combined with either unary minus or subtraction. +Note that traditionally the Perl function L rounds to 0, thus for +floating-point-like types one should follow the same semantic. If +C is unavailable, it can be autogenerated using the overloading of +C<0+>. + =item * I "bool", "\"\"", "0+", @@ -967,7 +974,7 @@ would would lead to a memory leak. Both these problems can be cured. Say, if we want to overload hash dereference on a reference to an object which is I as a hash itself, the only problem one has to circumvent is how to access -this I hash (as opposed to the I exhibited by +this I hash (as opposed to the I hash exhibited by the overloaded dereference operator). Here is one possible fetching routine: sub access_hash { @@ -979,7 +986,7 @@ overloaded dereference operator). Here is one possible fetching routine: $out; } -To move creation of the tied hash on each access, one may an extra +To remove creation of the tied hash on each access, one may an extra level of indirection which allows a non-circular structure of references: package two_refs1; @@ -1016,10 +1023,10 @@ level of indirection which allows a non-circular structure of references: $a->[$key]; } -Now if $baz is overloaded like this, then C<$bar> is a reference to a +Now if $baz is overloaded like this, then C<$baz> is a reference to a reference to the intermediate array, which keeps a reference to an actual array, and the access hash. The tie()ing object for the access -hash is also a reference to a reference to the actual array, so +hash is a reference to a reference to the actual array, so =over @@ -1106,7 +1113,7 @@ inside such a method it is not necessary to pretty-print the I $a and $b of an object. In the above subroutine C<"[$meth $a $b]"> is a catenation of some strings and components $a and $b. If these components use overloading, the catenation operator -will look for an overloaded operator C<.>, if not present, it will +will look for an overloaded operator C<.>; if not present, it will look for an overloaded operator C<"">. Thus it is enough to use use overload nomethod => \&wrap, '""' => \&str; @@ -1209,7 +1216,7 @@ mutator methods (C<++>, C<-=> and so on), does not do deep copying (not required without mutators!), and implements only those arithmetic operations which are used in the example. -To implement most arithmetic operations is easy, one should just use +To implement most arithmetic operations is easy; one should just use the tables of operations, and change the code which fills %subr to my %subr = ( 'n' => sub {$_[0]} ); @@ -1231,7 +1238,7 @@ special to make C<+=> and friends work, except filling C<+=> entry of way to know that the implementation of C<'+='> does not mutate the argument, compare L). -To implement a copy constructor, add C<'=' => \&cpy> to C +To implement a copy constructor, add C<< '=' => \&cpy >> to C line, and code (this code assumes that mutators change things one level deep only, so recursive copying is not needed):