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/**********************************************************************
prec.c -
$Author$
$Date$
created at: Tue Jan 26 02:40:41 2000
Copyright (C) 1993-2003 Yukihiro Matsumoto
**********************************************************************/
#include "ruby.h"
VALUE rb_mPrecision;
static ID prc_pr, prc_if;
/*
* call-seq:
* num.prec(klass) => a_klass
*
* Converts _self_ into an instance of _klass_. By default,
* +prec+ invokes
*
* klass.induced_from(num)
*
* and returns its value. So, if <code>klass.induced_from</code>
* doesn't return an instance of _klass_, it will be necessary
* to reimplement +prec+.
*/
static VALUE
prec_prec(VALUE x, VALUE klass)
{
return rb_funcall(klass, prc_if, 1, x);
}
/*
* call-seq:
* num.prec_i => Integer
*
* Returns an +Integer+ converted from _num_. It is equivalent
* to <code>prec(Integer)</code>.
*/
static VALUE
prec_prec_i(VALUE x)
{
VALUE klass = rb_cInteger;
return rb_funcall(x, prc_pr, 1, klass);
}
/*
* call-seq:
* num.prec_f => Integer
*
* Returns an +Float+ converted from _num_. It is equivalent
* to <code>prec(Float)</code>.
*/
static VALUE
prec_prec_f(VALUE x)
{
VALUE klass = rb_cFloat;
return rb_funcall(x, prc_pr, 1, klass);
}
/*
* call-seq:
* Mod.induced_from(number) => a_mod
*
* Creates an instance of mod from. This method is overridden
* by concrete +Numeric+ classes, so that (for example)
*
* Fixnum.induced_from(9.9) #=> 9
*
* Note that a use of +prec+ in a redefinition may cause
* an infinite loop.
*/
static VALUE
prec_induced_from(VALUE module, VALUE x)
{
rb_raise(rb_eTypeError, "undefined conversion from %s into %s",
rb_obj_classname(x), rb_class2name(module));
return Qnil; /* not reached */
}
/*
* call_seq:
* included
*
* When the +Precision+ module is mixed-in to a class, this +included+
* method is used to add our default +induced_from+ implementation
* to the host class.
*/
static VALUE
prec_included(VALUE module, VALUE include)
{
switch (TYPE(include)) {
case T_CLASS:
case T_MODULE:
break;
default:
Check_Type(include, T_CLASS);
break;
}
rb_define_singleton_method(include, "induced_from", prec_induced_from, 1);
return module;
}
/*
* Precision is a mixin for concrete numeric classes with
* precision. Here, `precision' means the fineness of approximation
* of a real number, so, this module should not be included into
* anything which is not a subset of Real (so it should not be
* included in classes such as +Complex+ or +Matrix+).
*/
void
Init_Precision(void)
{
rb_mPrecision = rb_define_module("Precision");
rb_define_singleton_method(rb_mPrecision, "included", prec_included, 1);
rb_define_method(rb_mPrecision, "prec", prec_prec, 1);
rb_define_method(rb_mPrecision, "prec_i", prec_prec_i, 0);
rb_define_method(rb_mPrecision, "prec_f", prec_prec_f, 0);
prc_pr = rb_intern("prec");
prc_if = rb_intern("induced_from");
}
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