Package 'bracer'

Bash-style brace expansion

Description

expand_braces() performs brace expansions on strings. str_expand_braces() is an alternate that returns a list of character vectors. Made popular by Unix shells, brace expansion allows users to concisely generate certain character vectors by taking a single string and (recursively) expanding the comma-separated lists and double-period-separated integer and character sequences enclosed within braces in that string. The double-period-separated numeric integer expansion also supports padding the resulting numbers with zeros.

Usage

expand_braces(string, engine = getOption("bracer.engine", NULL))

str_expand_braces(string, engine = getOption("bracer.engine", NULL))

Arguments

string	input character vector
engine	If 'r' use a pure R parser. If 'v8' use the 'braces' Javascript parser via the suggested V8 package. If NULL use 'v8' if 'V8' package detected else use 'r'; in either case send a message() about the choice unless ⁠getOption(bracer.engine.inform')⁠ is FALSE.

Value

expand_braces() returns a character vector while str_expand_braces() returns a list of character vectors.

Examples

expand_braces("Foo{A..F}", engine = "r")
  expand_braces("Foo{01..10}", engine = "r")
  expand_braces("Foo{A..E..2}{1..5..2}", engine = "r")
  expand_braces("Foo{-01..1}", engine = "r")
  expand_braces("Foo{{d..d},{bar,biz}}.{py,bash}", engine = "r")
  expand_braces(c("Foo{A..F}", "Bar.{py,bash}", "{{Biz}}"), engine = "r")
  str_expand_braces(c("Foo{A..F}", "Bar.{py,bash}", "{{Biz}}"), engine = "r")

---

Brace and Wildcard expansion on file paths

Description

glob() is a wrapper around Sys.glob() that uses expand_braces() to support both brace and wildcard expansion on file paths.

Usage

glob(paths, ..., engine = getOption("bracer.engine", NULL))

Arguments

paths	character vector of patterns for relative or absolute filepaths.
...	Passed to Sys.glob()
engine	If 'r' use a pure R parser. If 'v8' use the 'braces' Javascript parser via the suggested V8 package. If NULL use 'v8' if 'V8' package detected else use 'r'; in either case send a message() about the choice unless ⁠getOption(bracer.engine.inform')⁠ is FALSE.

Examples

dir <- system.file("R", package="bracer")
  path <- file.path(dir, "*.{R,r,S,s}")
  glob(path, engine = "r")

---