Re: 99 problems in Perl6: 32 and a question on number coercion
Hi! gabriele renzi [EMAIL PROTECTED] writes: Hi everyone! I solved the (easy) problem 32, implementing gcd($a,$b). You can check the code in the repository or on the web[1] I looked at [1]. What's the purpose of multi in this case? (Maybe you wanted to write it as more than one subs, did you?) But while writing this I noticed that a function written as sub gcd(Int $a, Int $b) still accepts float/rational values in input. I think I read once that a variable of type Int would accept these kind of assignment but that the value would be coerced to the new type of the variable, i.e. my Int $a= 10.1 #= 10 Could someone explain me what is the expected behaviour? Last time I experimented with this, the type system in Pugs looked unfinished. Type constraints were syntactically accepted but worked similar to typeless code in Perl5. I'm not sure about the current state. Anyway, in your example I hadn't expected a value coercion (from 10.1 to 10), but something like an error if the type doesn't match. But I can't find the right place in the synopses to verify it. Anyone with a clue here? Steffen -- Steffen Schwigon [EMAIL PROTECTED] Dresden Perl Mongers http://dresden-pm.org/ Deutscher Perl-Workshop http://www.perl-workshop.de/
Re: 99 problems in Perl6: 32 and a question on number coercion
Steffen Schwigon ha scritto: Hi! gabriele renzi [EMAIL PROTECTED] writes: Hi everyone! I solved the (easy) problem 32, implementing gcd($a,$b). You can check the code in the repository or on the web[1] I looked at [1]. What's the purpose of multi in this case? (Maybe you wanted to write it as more than one subs, did you?) look the comment: # Yet, it should be possible to define it even for commutative rings # other than Integers, so we use a multi sub. I think that in these examples we should respect the old good programmin' habits, including the stay open for extension idea. If we'd use a normal sub we would limit all the future user of gcd (which I expect to be legions ;) to using Int. snip Could someone explain me what is the expected behaviour? Last time I experimented with this, the type system in Pugs looked unfinished. Type constraints were syntactically accepted but worked similar to typeless code in Perl5. I'm not sure about the current state. I see Anyway, in your example I hadn't expected a value coercion (from 10.1 to 10), but something like an error if the type doesn't match. this is what I'd like to see too, since I think it could help avoiding casual errors, and the extensibility of the system is still safe because of the multi things. But I remember reading that, by default, perl6 will try to autocoerce arguments. -- blog en: http://www.riffraff.info blog it: http://riffraff.blogsome.com jabber : rff.rff at gmail dot com
Re: 99 problems in Perl6: 32 and a question on number coercion
gabriele renzi [EMAIL PROTECTED] writes: Steffen Schwigon ha scritto: I looked at [1]. What's the purpose of multi in this case? (Maybe you wanted to write it as more than one subs, did you?) look the comment: # Yet, it should be possible to define it even for commutative rings # other than Integers, so we use a multi sub. Damn, I ignored the comment as if it were my own. :-) Steffen -- Steffen Schwigon [EMAIL PROTECTED] Dresden Perl Mongers http://dresden-pm.org/ Deutscher Perl-Workshop http://www.perl-workshop.de/
99 problems in Perl6: 32 and a question on number coercion
Hi everyone! I solved the (easy) problem 32, implementing gcd($a,$b). You can check the code in the repository or on the web[1] But while writing this I noticed that a function written as sub gcd(Int $a, Int $b) still accepts float/rational values in input. I think I read once that a variable of type Int would accept these kind of assignment but that the value would be coerced to the new type of the variable, i.e. my Int $a= 10.1 #= 10 Could someone explain me what is the expected behaviour? [1] http://sial.org/pbot/22088 -- blog en: http://www.riffraff.info blog it: http://riffraff.blogsome.com jabber : rff.rff at gmail dot com
