You need to show what code you have currently.


On Sun, Feb 9, 2014 at 5:43 AM, Tonton San <lists / ruby-forum.com> wrote:

> I'm trying to evaluate an arithmetic operation of prefix type,
> "add(multiply(123,432),subtract(add(19,21),124))", can you make it so
> the regex engine scans it backwards?
>
> I'm trying to isolate each word and manipulate it without using split()
> and creating another array of o(n) space.
>
> I can parse the string from end to start by character and tokenize it
> using string index, but there must be someway to do this using regex
> efficiently.
>
> I know that split() creates an array that can be traversed backwards,
> but is there anyway to bypass the extra space required by split()? (Does
> the ruby interpreter/compiler somehow handle it?)
>
> Ultimately, is there anyway to make scan() parse a string backwards?
>
> Thanks
>
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> Posted via http://www.ruby-forum.com/.
>