Module#prepend

prepend(module, ...) → self

static VALUE
rb_mod_prepend(int argc, VALUE *argv, VALUE module)
{
    int i;
    ID id_prepend_features, id_prepended;

    if (BUILTIN_TYPE(module) == T_MODULE && FL_TEST(module, RMODULE_IS_REFINEMENT)) {
        rb_raise(rb_eTypeError, "Refinement#prepend has been removed");
    }

    CONST_ID(id_prepend_features, "prepend_features");
    CONST_ID(id_prepended, "prepended");

    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    for (i = 0; i < argc; i++) {
        Check_Type(argv[i], T_MODULE);
        if (FL_TEST(argv[i], RMODULE_IS_REFINEMENT)) {
            rb_raise(rb_eTypeError, "Cannot prepend refinement");
        }
    }
    while (argc--) {
        rb_funcall(argv[argc], id_prepend_features, 1, module);
        rb_funcall(argv[argc], id_prepended, 1, module);
    }
    return module;
}

Invokes Module.prepend_features on each parameter in reverse order.

Ruby version changes

3.1
- Module#prepend now modifies the ancestor chain if the receiver already includes the argument. Module#prepend still does not modify the ancestor chain if the receiver has already prepended the argument. [Bug #17423]
3.0
- Module#include and Module#prepend now affect classes and modules that have already included or prepended the receiver, mirroring the behavior if the arguments were included in the receiver before the other modules and classes included or prepended the receiver. [Feature #9573]
  
  Example
```
class C; end
module M1; end
module M2; end
C.include M1
M1.include M2
p C.ancestors #=> [C, M1, M2, Object, Kernel, BasicObject]
```

See also #name #prepended #module_function #prepend_features also in 4.1 · 4.0 · 3.4 · 3.2 · 3.1 · 3.0

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