Problem Statement

Provide a function or mechanism to convert a provided string into URL encoding representation. In URL encoding, special characters, control characters and extended characters are converted into a percent symbol followed by a two digit hexadecimal code, So a space character encodes into %20 within the string. For the purposes of this task, every character except 0-9, A-Z and a-z requires conversion, so the following characters all require conversion by default:

The string "http://foo bar/" would be encoded as "http%3A%2F%2Ffoo%20bar%2F".

It is permissible to use an exception string (containing a set of symbols that do not need to be converted). However, this is an optional feature and is not a requirement of this task.

Let's start with the solution:

      PRINT FNurlencode("http://foo bar/")
      END
      
      DEF FNurlencode(url$)
      LOCAL c%, i%
      WHILE i% < LEN(url$)
        i% += 1
        c% = ASCMID$(url$, i%)
        IF c%<&30 OR c%>&7A OR c%>&39 AND c%<&41 OR c%>&5A AND c%<&61 THEN
          url$ = LEFT$(url$,i%-1) + "%" + RIGHT$("0"+STR$~c%,2) + MID$(url$,i%+1)
        ENDIF
      ENDWHILE
      = url$