1 files changed, 141 insertions, 0 deletions
diff --git a/ruby_1_8_6/prec.c b/ruby_1_8_6/prec.c
new file mode 100644
index 0000000000..7b215fba09
--- /dev/null
+++ b/ruby_1_8_6/prec.c
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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(x, klass)
+    VALUE x, 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(x)
+    VALUE x;
+{
+    VALUE klass = rb_cInteger;
+
+    return rb_funcall(x, prc_pr, 1, klass);
+}
+
+/*
+ *  call-seq:
+ *    num.prec_f  =>  Float
+ *
+ *  Returns a +Float+ converted from _num_. It is equivalent 
+ *  to <code>prec(Float)</code>.
+ */
+
+static VALUE
+prec_prec_f(x)
+    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(module, x)
+    VALUE module, 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(module, include)
+    VALUE module, 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()
+{
+    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");
+}