Constrained genericity: Difference between revisions

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let your_box = FloatBox.make_box_from_list [2.3; 4.5]</lang>

Unfortunately, it is kind of cumbersome in that, for every type parameter we want to use for this generic type, we will have to explicitly create a module for the resulting type (i.e. <tt>BananaBox</tt>, <tt>FloatBox</tt>). And the operations on that resulting type (i.e. <tt>make_box_from_list</tt>) are tied to each specific module.

=={{header|ooRexx}}==

ooRexx methods, routines, and collections are all untyped, so there are no language-level checks for type matches. Tests for identity need to be performed at runtime using mechanisms such as the object isA method.

call dinnerTime "yogurt"

call dinnerTime .pizza~new

call dinnerTime .broccoli~new

-- a mixin class that defines the interface for being "food", and

-- thus expected to implement an "eat" method

::class food mixinclass object

::method eat abstract

::class pizza subclass food

::method eat

Say "mmmmmmmm, pizza".

-- mixin classes can also be used for multiple inheritance

::class broccoli inherit food

::method eat

Say "ugh, do I have to?".

::routine dinnerTime

use arg dish

-- ooRexx arguments are typeless, so tests for constrained

-- types must be peformed at run time. The isA method will

-- check if an object is of the required type

if \dish~isA(.food) then do

say "I can't eat that!"

return

end

else dish~eat

</lang>

=={{header|Perl 6}}==