[Rd] Question about Unix file paths

[John W. Eaton]

On 26-Nov-2003, Martin Maechler <maechler at stat.math.ethz.ch> wrote:

| >>>>> " Kurt" == Kurt Hornik <Kurt.Hornik at wu-wien.ac.at>
| >>>>>     on Wed, 26 Nov 2003 10:05:42 +0100 writes:
| 
|      Kurt> Right.  In any case, an explicit glob() function
|      Kurt> seems preferable to me ...
| 
| Good idea!
| 
| More than 12 years ago, I had a similar one, and wrote  a
| "pat2grep()" {pattern to grep regular expression} function
| --- for S-plus on Unix ---  which I have now renamed to  glob2regexp():
| -- still not really usable outside unix (or windows with the
| 'sed' tool in the path), nor perfect, but maybe a good start:
| 
| sys <- function(...) system(paste(..., sep = ""))
| 
| glob2regexp <- function(pattern)
| {
|   ## Purpose: Change "ls pattern" to "grep regular expression" pattern.
|   ## -------------------------------------------------------------------------
|   ## Author: Martin Maechler ETH Zurich, ~ 1991
|   sys("echo '", pattern, "'| sed ",
|       "'s/\\./\\\\./g;s/*/.*/g;s/?/./g; s/^/^/;s/$/$/; s/\\.\\*\\$$//'")
| }

It seems to me that using this approach to implement a proper glob()
function would be more work than using the glob code that is available
as part of bash, which I think will allow you to handle much more
complex patterns, including [xyz] {a,b,c} etc.

jwe