| # File src/library/utils/R/glob2rx.R |
| # Part of the R package, https://www.R-project.org |
| # |
| # Copyright (C) 1995-2015 The R Core Team |
| # |
| # This program is free software; you can redistribute it and/or modify |
| # it under the terms of the GNU General Public License as published by |
| # the Free Software Foundation; either version 2 of the License, or |
| # (at your option) any later version. |
| # |
| # This program is distributed in the hope that it will be useful, |
| # but WITHOUT ANY WARRANTY; without even the implied warranty of |
| # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| # GNU General Public License for more details. |
| # |
| # A copy of the GNU General Public License is available at |
| # https://www.R-project.org/Licenses/ |
| |
| glob2rx <- function(pattern, trim.head = FALSE, trim.tail = TRUE) |
| { |
| ## special case, since paste ignores 0-length inputs (PR#16205) |
| if(!length(pattern)) return(character()) |
| |
| ## Purpose: Change 'ls' aka 'wildcard' aka 'globbing' _pattern_ to |
| ## Regular Expression (as in grep, perl, emacs, ...) |
| ## ------------------------------------------------------------------------- |
| ## Author: Martin Maechler ETH Zurich, ~ 1991 |
| ## New version using [g]sub() : 2004 |
| p <- gsub("\\.","\\\\.", paste0("^", pattern, "$")) |
| p <- gsub("\\?", ".", gsub("\\*", ".*", p)) |
| ## 'Escaping hell' : at least for '(', '[' and '{' |
| p <- gsub("([^\\])\\(", "\\1\\\\(", p) |
| p <- gsub("([^\\])\\[", "\\1\\\\[", p) |
| p <- gsub("([^\\])\\{", "\\1\\\\{", p) |
| ## these are trimming ".*$" and "^.*" - in most cases only for aesthetics |
| if(trim.tail) p <- sub("\\.\\*\\$$", "", p) |
| if(trim.head) p <- sub("\\^\\.\\*", "", p) |
| p |
| } |