% File src/library/utils/man/glob2rx.Rd
% Part of the R package, http://www.R-project.org
% Copyright 1995-2007 R Core Development Team
% Distributed under GPL 2 or later

\name{glob2rx}
\alias{glob2rx}
\title{Change Wildcard or Globbing Pattern into Regular Expression}
\description{
  Change \emph{wildcard} aka \emph{globbing} patterns into the
  corresponding regular expressions (\code{\link{regexp}}).
}
\usage{
glob2rx(pattern, trim.head = FALSE, trim.tail = TRUE)
}
\arguments{
  \item{pattern}{character vector}
  \item{trim.head}{logical specifying if leading \code{"^.*"} should be
    trimmed from the result.}
  \item{trim.tail}{logical specifying if trailing \code{".*$"} should be
    trimmed from the result.}
}
\details{
  This takes a wildcard as used by most shells and returns an equivalent
  regular expression.  \code{?} is mapped to \code{.} (match a single
  character), \code{*} to \code{.*} (match any string, including an
  empty one), and the pattern is anchored (it must start at the
  beginning and end at the end).  Optionally, the resulting regexp is
  simplified.
}
\value{
  A character vector of the same length as the input \code{pattern}
  where each wildcard is translated to the corresponding
  regular expression.
}
\author{Martin Maechler, Unix/sed based version, 1991; current: 2004}
\seealso{
  \code{\link{regexp}} about regular expression,
  \code{\link{sub}}, etc about substitutions using regexps.
}
\examples{
stopifnot(glob2rx("abc.*") == "^abc\\\\.",% '\\' doubled in Rd file!
          glob2rx("a?b.*") == "^a.b\\\\.",
          glob2rx("a?b.*", trim.tail=FALSE) == "^a.b\\\\..*$",
          glob2rx("*.doc") == "^.*\\\\.doc$",
          glob2rx("*.doc", trim.head=TRUE) == "\\\\.doc$",
          glob2rx("*.t*")  == "^.*\\\\.t",
          glob2rx("*.t??") == "^.*\\\\.t..$"
)
}
\keyword{file}
\keyword{character}
\keyword{utilities}