From: Park Heesob <phasis@...>
Date: 2002-07-04T12:54:37+09:00
Subject: Re: the pains of parsing


"Tom Sawyer" <transami@transami.net> wrote in message
news:1025743968.2467.123.camel@silver...
> i find myself spending alot of time writing routines to parse complex
> strings. here's a mock example string of my current problem:
>
> a<b>[c]{d}"e"f {{g}} [[h]]*i**j*"k"
>
> and i want to parse this into an array like so:
>
> ['a','<b>','[c]','{d}','"e"','f','{{g}}','[[h]]','*i*','*j*','"k"']
>
> for clearity here's another example:
>
> "a"{{b}}c{d}<e>  ->  ['"a"','{{b}}','c','{d}','<e>']
>
> i have found such strings difficult to parse for a number of reasons.
> first, the text in double-quotations could contain bracket symbols but
> must be treated as plain text. second, [ and { brackets can be nested as
> in g and h of the first example. and finally, because whitespace can
> optionally occur between the parts.
>
> i wish ruby had some sort of parsing tool to make this childs play.
>
> can any of you geniuses out there offer an elegent solution? my current
> code dosen't work 100% and is like 90+ lines long. ugghh!
>
> ~transami
>
Hi?

How about this?

--------------------------------------------------
str = 'a<b>[c]{d}"e"f {{g}} [[h]]*i**j*"k"'

s = ['<','[','{','"','*']
e = ['>',']','}','"','*']
arr = []

str.gsub!(' ','')
i = 0
while i< str.length

  if not s.include?(str[i,1])
        for j in i ... str.length
          if s.include?(str[j,1])
            arr << str[i..j-1]
            i = j
            break
          end
        end
  end

  for j in 0 ... s.length
    if str[i,1] == s[j]
      if s[j]=='"' || s[j]=='*'
        k = str.index(e[j],i+1)
      else
        k = i
        k += 1 while str[k,1]==s[j]

        for k in str.index(e[j],k) ... str.length
          if str[k,1]!=e[j]
            k -= 1
            break
          end
        end
      end
      arr << str[i..k]
      i = k+1
      break
    end
  end

end

p arr
---------------------------------------------

Park Heesob.