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> For example, in languages like Perl, JavaScript, and CoffeeScript adding a string to a number is permissible (e.g., "5" + 2 yields "52"). The same operation y

> For example, in languages like Perl, JavaScript, and CoffeeScript adding a string to a number is permissible (e.g., "5" + 2 yields "52"). The same operation yields 7 in Php. Such an operation is not permitted in languages such as Java and Python as they do not allow implicit conversion. Regarding Perl, the quoted statement is wrong: $ perl -E 'say "5" + 2' 7 Furthermore, this is not an implicit conversion. The + operator is an explicit numeric conversion. Here's a more detailed description: https://codespeaks.blogspot.ca/2007/09/ruby-and-python-overload-operator-for.html https://codespeaks.blogspot.ca/2007/09/ruby-and-python-overl...

gipp 9y ago
Your link seems to argue that the simple fact that it's common convention makes it explicit, which doesn't really seem to hold water.
- hoytech 9y ago
  Consider this javascript function: function add(a,b) { return a + b; } Although no conversion is requested explicitly in the function definition, a conversion may take place depending on the types of the arguments passed in: > add(1,2) 3 >add("1",2) "12" The article in question defines implicit conversion in this way, and in my experience it's a fairly common term. I was pointing out that per this definition, the article is wrong in saying that perl's + operator may perform an implicit conversion. In perl the + operator always performs a numeric conversion of both its operands, regardless of types. By writing + you are explicitly requesting numeric conversion of both arguments. In general perl doesn't perform implicit conversion (of course there are some exceptions -- it is perl after all). It does this by not overloading operators like + for different operations such as addition and concatenation. This also has the nice property that you can count on a+b == b+a, unlike python for instance. (However, in python PEP-465, non-commutativity was a stated advantage of adopting @ for matrix multiplication instead of overloading *, go figure).
agrafix 9y ago
The + operator is not an explicit numeric conversion. What numeric type is it converting to? In Python you can also combine two lists using the + operator. Haskell for example requires to be explicit about this: y = (read "5" :: Int) + 5
- hoytech 9y ago
  Please see my sibling reply. I was referring to perl, not python or haskell.

gipp 9y ago

Your link seems to argue that the simple fact that it's common convention makes it explicit, which doesn't really seem to hold water.

hoytech 9y ago
Consider this javascript function: function add(a,b) { return a + b; } Although no conversion is requested explicitly in the function definition, a conversion may take place depending on the types of the arguments passed in: > add(1,2) 3 >add("1",2) "12" The article in question defines implicit conversion in this way, and in my experience it's a fairly common term. I was pointing out that per this definition, the article is wrong in saying that perl's + operator may perform an implicit conversion. In perl the + operator always performs a numeric conversion of both its operands, regardless of types. By writing + you are explicitly requesting numeric conversion of both arguments. In general perl doesn't perform implicit conversion (of course there are some exceptions -- it is perl after all). It does this by not overloading operators like + for different operations such as addition and concatenation. This also has the nice property that you can count on a+b == b+a, unlike python for instance. (However, in python PEP-465, non-commutativity was a stated advantage of adopting @ for matrix multiplication instead of overloading *, go figure).

agrafix 9y ago

The + operator is not an explicit numeric conversion. What numeric type is it converting to? In Python you can also combine two lists using the + operator. Haskell for example requires to be explicit about this: y = (read "5" :: Int) + 5

hoytech 9y ago
Please see my sibling reply. I was referring to perl, not python or haskell.