From: Logan Capaldo <logancapaldo@...>
Date: 2007-05-21T22:28:56+09:00
Subject: Re: Dynamically creating ruby source files

On 5/19/07, Matt Gretton <matthew.gretton@gmail.com> wrote:
> Hello all,
>
> What techniques do people generally use to create files and write ruby
> code to them?
>
> One way of acheving this (a horrible way) would be just to write the
> correct code to a file as follows. (This just creates a file called
> file_test.rb that defines a module with two methods)
>
>
> passed_in_name = "module1"
> passed_in_methods = ["meth1","meth2"]
>
> File.open("test_file.rb","w") do |file|
>    file.puts "module #{passed_in_name}"
>    file.puts
>
>    passed_in_methods.each do |meth|
>       file.puts "\tdef #{meth}"
>       file.puts "\t\t\#insert method code here"
>       file.puts "\tend"
>       file.puts
>    end
>
>    file.puts "end"
> end
>
> I feel there must exist a more elegant way of creating a file liek this.
> For example, I have heard that ruby on rails dynamically creates files
> containing ruby code. This behavior seems pretty common to various ruby
> projects, for example I know rails creates ruby source code dynamically.
> Not having had experience with such projects I have tried  in vain to
> search google for information.
>
> Any advice or generally a point the right direction (to other resources
> etc) would be greatly appreciated.
>

I don't know that you necessarily want to create a file full of ruby
source (you might) but alternatively you can use ruby's
meta-programming facilities:

passed_in_name = "Module1"
passed_in_methods = ["meth1", "meth2"]

mod = Module.new
Object.const_set(passed_in_name, mod)

mod.module_eval do
  passed_in_methods.each do |m|
    define_method(m) do |arg1, arg2, ..., argn|
        body_of_method
    end
  end
end

> Thanks in advance.
>
> Matt.
>
> --
> Posted via http://www.ruby-forum.com/.
>
>