Using ruby's BigDecimal in the C API

Question

In order to create a BigDecimal from a C string in a Ruby extension, I'm doing this:

rb_funcall(rb_path2class("BigDecimal"), rb_intern("new"), 1, rb_str_new("0.0777", 6));
// => BigDecimal.new("0.0777")

Is there a shorter way to do this?

Also, stupid question, but is there an 'official' documentation for the C API (ruby 1.9.3), or does it just come down to reading the headers?

There's never a short way to go backwards. – Ignacio Vazquez-Abrams Mar 31 '12 at 05:16 — Ignacio Vazquez-Abrams, Mar 31 '12 at 05:16

score 2 · Answer 1 · answered Mar 31 '12 at 07:09

2

I do not get what the problem really is. You do like it shorter? Write a wrapper.

rb_object new_big_decimal(char * from) {
       rb_funcall(rb_path2class("BigDecimal"), rb_intern("new"), 1, rb_str_new(from, 6));
 }

Of course it may not be rb_object but something else, but what is the problem?

answered Mar 31 '12 at 07:09

Friedrich

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No problem, I just thought all the numeric types may have had macros, like how in ruby you don't need `BigDecimal.new(..)`, as `BigDecimal(..)` will suffice. Was just wondering if I was doing it wrong :) – d11wtq Mar 31 '12 at 10:03

score 1 · Accepted Answer · answered Mar 31 '12 at 11:08

Unfortunately, the initialize function, and pretty much the entire BigDecimal C API, is declared as static and is thus not exposed.

The best way to learn about the C implementation of Ruby, and its API, is to browse the source, especially the ext directory. There is also the README.EXT file, which describes the general API.

Using ruby's BigDecimal in the C API

2 Answers2