From: Wilbert Berendsen <wbsoft@...4all.nl>
Date: 2001-06-08T21:47:29+09:00
Subject: [ruby-talk:16325] Tcl string map lookalike

Hi,

What's the best way to perfomrs a Tcl-like "string map" function.

Tcl "string map" walks through a string, replacing every occurrence of a
substring with an associated replacement.  The substrings and replacement
are in a flat list, and the list is searched from the beginning, so first
matches precede, eg:

Tcl:

set str "This is a &lt;string$gt;"
set map [list "&lt;" "<" "&lt;" ">" "&lt" "<" "&gt" ">"]
string map $map $str
===> "This is a <string>"

Ruby: (????)

str = "This is a string"
map = ["&lt;", "<", "&lt;", ">", "&lt", "<", "&gt", ">"]
str.map (map)
===> "This is a <string>"

I tried using gsub with an array and a special regexp, but that's a bit
cumbersome. Separate gsub's after eachother don't work, because the
substitutions may again contain matching character which results in
errors.  So it must do it in one single pass along the string.

Any ideas?

Thanx,
Wilbert



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