Replacing Characters In A String (Updated)

While I am working on the Factor package manager, I came across an interesting problem:

"how to replace certain characters with other characters in a string".

I have been looking at a few solutions. The first solution that I came up with was:

 : url>path ( URL -- path )
     "" swap
     [
         1string
         {
             { ":" [ "-" ] }
             { "/" [ "-" ] }
             [ "%" [ "-" ] }
             [ "~" [ "-" ] }
             [ "@" [ "-" ] }
             [ ]
         } case append
     ] each ;        

After some chatting on IRC (thanks tizoc) I changed the solution to:

 : url>path ( URL -- path )
     [
         {
           { CHAR: :  [ CHAR: - ] }
           { CHAR: /  [ CHAR: - ] }
           { CHAR: %  [ CHAR: - ] }
           { CHAR: ~  [ CHAR: - ] }
           { CHAR: @  [ CHAR: - ] }                
           [ ]
         } case
     ] map ;

In both solutions, I am transforming specific characters to 1 character, but this need not be the case. The solution im looking for will need to support transforming to multiple characters if needed.

To use the above word you would type:

 "abc:/%" url>path
      => "abc---"

After talking to erg on #concatenative, I changed the code to use the
replace word in the sequences.lib vocabulary:

 : url>path ( URL -- path )
     ":/%~@" "-----" replace ;