Warning: This feature is experimental: it has known issues and its behavior may change in the future.
In Asymptote, it is possible to create modules that must have one or more
types specified when they are imported. The first executable line of any such
module must be of the form typedef import(<types>), where
<types> is a list of required type parameters. For instance,
typedef import(T, S, Number);
could be the first line of a module that requires three type parameters. The
remaining code in the module can then use T, S, and Number
as types.
To import such a module, one must specify the types to be used. For instance,
if the module above were named templatedModule, it could be accessed
for types string, int[], and real with the import
command
access templatedModule(T=string, S=int[], Number=real)
as templatedModule_string_int_real;
Note that this is actually an access command rather than an
import command, so the names of types, functions, etc. would have to be
stated as e.g. templatedModule_string_int_real.Wrapper_Number rather than
just Wrapper_Number (where Wrapper_Number is a type defined in
templatedModule.asy).
Alternatively, the module could be imported via a command like
from templatedModule(T=string, S=int[], Number=real) access
Wrapper_Number as Wrapper_real,
operator ==;
This command would automatically rename Wrapper_Number to
Wrapper_real and would also allow the use of any operator ==
overloads defined in the module.
For more information, see the examples in https://github.com/vectorgraphics/asymptote/tree/647b6c5732ec94a48f0f0b2446f02c86888fe7e7/tests/template.
Issues: Certain standard features of almost any type (such as
==, new, and the ability to call static methods on the type) may
only be available for type arguments that are builtin or defined in the plain module.