git-path.r

library(memoise)
library(stringr)

git_prompt <- function() {
  git <- find_git()
  if (is.null(git)) stop("Git not installed", call. = FALSE)
  if (!in_git_repo(git)) stop("Not in git repo", call. = FALSE)
  
  
  update <- function(...) update_prompt(git)
  addTaskCallback(update, name = "git")
  update()
  
  invisible(TRUE)
}

find_git <- memoise(function() {
  if (on_path("git")) return("git")
  if (on_path("git.exe")) return("git")
  NULL
})

update_prompt <- function(git = find_git()) {
  if (in_git_repo()) {
    prompt <- paste("(", git_branch(git), ")", 
      if (is_dirty(git)) "*", "> ", sep = "")    
  } else {
    prompt <- "> "
  }
  options(prompt = prompt)
  
  invisible(TRUE)
}
git_branch <- function(git = find_git()) {
  system2(git, "symbolic-ref --short -q HEAD", stdout = TRUE, stderr = FALSE)
}
is_dirty <- function(git = find_git()) {
  system2(git, "diff-index HEAD --quiet", stdout = FALSE) == 1
}
in_git_repo <- function(git = find_git()) {
  system2(git, "rev-parse", stdout = FALSE, stderr = FALSE) == 0
}

Does on_path() require devtools?

Is there any plans to put this into the devtools package? That would be kinda cool.

library(devtools)
git_prompt()

on_path doesn't appear to be a part of the devtools package anymore. Has it been moved to another package? Is there an alternative function that can be used?