From: Eric Bennett <ericb@...>
Date: 2001-05-01T23:32:11+09:00
Subject: [ruby-talk:14489] Re: How to do it the Ruby-way 2

On Tue, 1 May 2001, Stefan Matthias Aust wrote:

>  def a(pat, name)
>   eval "print \"#{pat}\""
>  end
> 
> But, I think, it's really ugly.  I'd like to use a pattern string read
> in from an external file (from the trusted source) and then emit it
> using all bindings currently available in that method.  How can this
> be achieved?

I don't know how to get rid of the eval, but you can move the print out of
it and get it into a nice functional form:


def expression_for_string( string )
	'"' + string.gsub( /(["\\])/, '\\\\\1' ) + '"'
end

def with_binding_expand( name_binding, string_template )
	eval expression_for_string( string_template ), name_binding
end

def a( string_template, name )
	print with_binding_expand( binding, string_template )
end


a( "My name is \#{name}\n", "fred" )
a( "My 'na\\me\" is \#{name}\n", "charles" )
a( "My quine is almost \"\#{string_template}\"\n", "Ignored" ) 


   - Eric B.

--
"Bound to please"