diff options
Diffstat (limited to 'proc.c')
-rw-r--r-- | proc.c | 54 |
1 files changed, 54 insertions, 0 deletions
@@ -3046,6 +3046,59 @@ rb_method_curry(int argc, const VALUE *argv, VALUE self) return proc_curry(argc, argv, proc); } +static VALUE +compose(VALUE dummy, VALUE args, int argc, VALUE *argv, VALUE passed_proc) +{ + VALUE f, g, fargs; + f = RARRAY_AREF(args, 0); + g = RARRAY_AREF(args, 1); + fargs = rb_ary_new3(1, rb_proc_call_with_block(g, argc, argv, passed_proc)); + + return rb_proc_call(f, fargs); +} + +/* + * call-seq: + * prc * g -> a_proc + * + * Returns a proc that is the composition of this proc and the given proc <i>g</i>. + * The returned proc takes a variable number of arguments, calls <i>g</i> with them + * then calls this proc with the result. + * + * f = proc {|x| x * 2 } + * g = proc {|x, y| x + y } + * h = f * g + * p h.call(1, 2) #=> 6 + */ +static VALUE +proc_compose(VALUE self, VALUE g) +{ + VALUE proc, args; + rb_proc_t *procp; + int is_lambda; + + if (!rb_obj_is_method(g) && !rb_obj_is_proc(g)) { + rb_raise(rb_eTypeError, + "wrong argument type %s (expected Proc/Method)", + rb_obj_classname(g)); + } + + if (rb_obj_is_method(g)) { + g = method_to_proc(g); + } + + args = rb_ary_new3(2, self, g); + + GetProcPtr(self, procp); + is_lambda = procp->is_lambda; + + proc = rb_proc_new(compose, args); + GetProcPtr(proc, procp); + procp->is_lambda = is_lambda; + + return proc; +} + /* * Document-class: LocalJumpError * @@ -3142,6 +3195,7 @@ Init_Proc(void) rb_define_method(rb_cProc, "lambda?", rb_proc_lambda_p, 0); rb_define_method(rb_cProc, "binding", proc_binding, 0); rb_define_method(rb_cProc, "curry", proc_curry, -1); + rb_define_method(rb_cProc, "*", proc_compose, 1); rb_define_method(rb_cProc, "source_location", rb_proc_location, 0); rb_define_method(rb_cProc, "parameters", rb_proc_parameters, 0); |