From a15b1480af3dfb2993d5e89e4e9d168d0dd91c2c Mon Sep 17 00:00:00 2001
From: Philipp Baumann <baumann-philipp@proton.me>
Date: Wed, 9 Aug 2023 19:20:59 +0200
Subject: [PATCH] change order of args; fix exec cmd

---
 R/find_rev.R       | 18 ++++++++++--------
 dev/build_envs.Rmd | 18 ++++++++++--------
 man/nix_build.Rd   | 15 ++++++++-------
 3 files changed, 28 insertions(+), 23 deletions(-)

diff --git a/R/find_rev.R b/R/find_rev.R
index 2f50acf8..dd197af1 100644
--- a/R/find_rev.R
+++ b/R/find_rev.R
@@ -390,21 +390,23 @@ USE_RSTUDIO};
 
 
 #' Invoke shell command `nix-build` from an R session
-#' @param exec_mode Either `"blocking"` (default) or `"non-blocking`. This
-#' will either block the R session while the `nix-build` shell command is
-#' executed, or run `nix-build` in the background ("non-blocking").
 #' @param nix_file File path to the `default.nix` file. The default is
 #' a `default.nix` file in the current working directory of the current R
 #' session.
-#' @return invisible
+#' @param exec_mode Either `"blocking"` (default) or `"non-blocking`. This
+#' will either block the R session while the `nix-build` shell command is
+#' executed, or run `nix-build` in the background ("non-blocking").
+#' @return integer of the process ID (PID) of `nix-build` shell command
+#' launched.
 #' @export
-nix_build <- function(exec_mode = c("blocking", "non-blocking"),
-                      nix_file = file.path("default.nix")) {
+nix_build <- function(nix_file = file.path("default.nix"),
+                      exec_mode = c("blocking", "non-blocking")) {
+  stopifnot(is.character(nix_file))
   exec_mode <- match.arg(exec_mode)
   
   proc <- switch(exec_mode,
-    "blocking" = sys::exec_wait(cmd = "nix-build"),
-    "non-blocking" = sys::exec_background(cmd = "nix-build"),
+    "blocking" = sys::exec_wait("nix-build", nix_file),
+    "non-blocking" = sys::exec_background("nix-build", nix_file),
     stop('invalid `exec_mode`. Either use "blocking" or "non-blocking"')
   )
   
diff --git a/dev/build_envs.Rmd b/dev/build_envs.Rmd
index 00d0b66e..eaa3ccb8 100644
--- a/dev/build_envs.Rmd
+++ b/dev/build_envs.Rmd
@@ -476,21 +476,23 @@ session.
 
 ```{r function-nix_build}
 #' Invoke shell command `nix-build` from an R session
-#' @param exec_mode Either `"blocking"` (default) or `"non-blocking`. This
-#' will either block the R session while the `nix-build` shell command is
-#' executed, or run `nix-build` in the background ("non-blocking").
 #' @param nix_file File path to the `default.nix` file. The default is
 #' a `default.nix` file in the current working directory of the current R
 #' session.
-#' @return invisible
+#' @param exec_mode Either `"blocking"` (default) or `"non-blocking`. This
+#' will either block the R session while the `nix-build` shell command is
+#' executed, or run `nix-build` in the background ("non-blocking").
+#' @return integer of the process ID (PID) of `nix-build` shell command
+#' launched.
 #' @export
-nix_build <- function(exec_mode = c("blocking", "non-blocking"),
-                      nix_file = file.path("default.nix")) {
+nix_build <- function(nix_file = file.path("default.nix"),
+                      exec_mode = c("blocking", "non-blocking")) {
+  stopifnot(is.character(nix_file))
   exec_mode <- match.arg(exec_mode)
   
   proc <- switch(exec_mode,
-    "blocking" = sys::exec_wait(cmd = "nix-build"),
-    "non-blocking" = sys::exec_background(cmd = "nix-build"),
+    "blocking" = sys::exec_wait("nix-build", nix_file),
+    "non-blocking" = sys::exec_background("nix-build", nix_file),
     stop('invalid `exec_mode`. Either use "blocking" or "non-blocking"')
   )
   
diff --git a/man/nix_build.Rd b/man/nix_build.Rd
index 3c6bed09..b5a46411 100644
--- a/man/nix_build.Rd
+++ b/man/nix_build.Rd
@@ -5,21 +5,22 @@
 \title{Invoke shell command \code{nix-build} from an R session}
 \usage{
 nix_build(
-  exec_mode = c("blocking", "non-blocking"),
-  nix_file = file.path("default.nix")
+  nix_file = file.path("default.nix"),
+  exec_mode = c("blocking", "non-blocking")
 )
 }
 \arguments{
-\item{exec_mode}{Either \code{"blocking"} (default) or \verb{"non-blocking}. This
-will either block the R session while the \code{nix-build} shell command is
-executed, or run \code{nix-build} in the background ("non-blocking").}
-
 \item{nix_file}{File path to the \code{default.nix} file. The default is
 a \code{default.nix} file in the current working directory of the current R
 session.}
+
+\item{exec_mode}{Either \code{"blocking"} (default) or \verb{"non-blocking}. This
+will either block the R session while the \code{nix-build} shell command is
+executed, or run \code{nix-build} in the background ("non-blocking").}
 }
 \value{
-invisible
+integer of the process ID (PID) of \code{nix-build} shell command
+launched.
 }
 \description{
 Invoke shell command \code{nix-build} from an R session