Module Interface File

A module's public interface is contained in a module interface file, conventionally with the .m suffix. It is analogous to the C/C++ header file (.h).

The Inferno Reference API module interface files are conventionally stored in the <inferno_root>/module directory.

A module interface file declares the public data and function members. It specifies the types and function interfaces that can be used by other programs. It is the module interface declaration.

Program Listing 3-1 is an example of a simple module interface file.

Program Listing 3-1 greet.m

1. Greet: module {
2. init: fn(ctxt: ref Draw->Context, argv: list of string);
3. };

Program Listing 3-2 shows another small example, the Random Module of the Inferno Reference API (in the <inferno_root>/module/rand.m file).

Program Listing 3-2 rand.m

1. Rand: module
2. {
3. PATH: con "/dis/lib/rand.dis";
4. # init sets a seed
5. init: fn(seed: int);
6. # rand returns something in 0 .. modulus-1
7. # (if 0 < modulus < 2^31)
8. rand: fn(modulus: int): int;
9. # (if 0 < modulus < 2^53)
10. bigrand: fn(modulus: big): big;
11. };