From 471fff182b632fc3b6f99925ff6c7bd25850a841 Mon Sep 17 00:00:00 2001
From: David Thompson <address@hidden>
Date: Sun, 9 Aug 2015 11:35:51 -0400
Subject: [PATCH] scripts: package: Add --install-from-file option.

* guix/scripts/package.scm (show-help): Add help text for --install-from-file
  option.
  (%options): Add --install-from-file option.
* doc/guix.texi ("invoking guix package"): Document it.
* doc/package-hello.scm: New file.
* doc.am (EXTRA_DIST): Add it.
---
 doc.am                   |  3 ++-
 doc/guix.texi            | 18 +++++++++++++++++-
 doc/package-hello.scm    | 18 ++++++++++++++++++
 guix/scripts/package.scm | 10 ++++++++++
 4 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 doc/package-hello.scm

diff --git a/doc.am b/doc.am
index 02b80ec..1f0b832 100644
--- a/doc.am
+++ b/doc.am
@@ -26,7 +26,8 @@ EXTRA_DIST +=					\
   doc/images/bootstrap-graph.eps		\
   doc/images/bootstrap-graph.pdf		\
   doc/images/coreutils-size-map.eps		\
-  doc/environment-gdb.scm
+  doc/environment-gdb.scm			\
+  doc/package-hello.scm
 
 OS_CONFIG_EXAMPLES_TEXI =			\
   doc/os-config-bare-bones.texi			\
diff --git a/doc/guix.texi b/doc/guix.texi
index a20bca6..5550582 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -1167,6 +1167,22 @@ Note that this option installs the first output of the specified
 package, which may be insufficient when needing a specific output of a
 multiple-output package.
 
address@hidden address@hidden
address@hidden -f @var{file}
+Install the package that the code within @var{file} evaluates to.
+
+As an example, @var{file} might contain a definition like this
+(@pxref{Defining Packages}):
+
address@hidden
address@hidden package-hello.scm
address@hidden example
+
+Developers may find it useful to include such a @file{package.scm} file
+in the root of their project's source tree that can be used to test
+development snapshots and create reproducible development environments
+(@pxref{Invoking guix environment}).
+
 @item address@hidden @dots{}
 @itemx -r @var{package} @dots{}
 Remove the specified @var{package}s.
@@ -2841,7 +2857,7 @@ omitted since it will take place implicitly, as we will see later
 @end example
 
 @c See
address@hidden <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/> 
address@hidden <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
 @c for the funny quote.
 Calling the monadic @code{sh-symlink} has no effect.  As someone once
 said, ``you exit a monad like you exit a building on fire: by running''.
diff --git a/doc/package-hello.scm b/doc/package-hello.scm
new file mode 100644
index 0000000..b3fcd4f
--- /dev/null
+++ b/doc/package-hello.scm
@@ -0,0 +1,18 @@
+(use-modules (guix)
+             (guix build-system gnu)
+             (guix licenses))
+
+(package
+  (name "hello")
+  (version "2.8")
+  (source (origin
+            (method url-fetch)
+            (uri (string-append "mirror://gnu/hello/hello-" version
+                                ".tar.gz"))
+            (sha256
+             (base32 "0wqd8sjmxfskrflaxywc7gqw7sfawrfvdxd9skxawzfgyy0pzdz6"))))
+  (build-system gnu-build-system)
+  (synopsis "Hello, GNU world: An example GNU package")
+  (description "Guess what GNU Hello prints!")
+  (home-page "http://www.gnu.org/software/hello/")
+  (license gpl3+))
diff --git a/guix/scripts/package.scm b/guix/scripts/package.scm
index b545ea2..23f1597 100644
--- a/guix/scripts/package.scm
+++ b/guix/scripts/package.scm
@@ -381,6 +381,10 @@ Install, remove, or upgrade packages in a single transaction.\n"))
   -e, --install-from-expression=EXP
                          install the package EXP evaluates to"))
   (display (_ "
+  -f, --install-from-file=FILE
+                         install the package that the code within FILE
+                         evaluates to"))
+  (display (_ "
   -r, --remove PACKAGE ...
                          remove PACKAGEs"))
   (display (_ "
@@ -454,6 +458,12 @@ Install, remove, or upgrade packages in a single transaction.\n"))
                    (values (alist-cons 'install (read/eval-package-expression arg)
                                        result)
                            #f)))
+         (option '(#\f "install-from-file") #t #f
+                 (lambda (opt name arg result arg-handler)
+                   (values (alist-cons 'install
+                                       (load* arg (make-user-module '()))
+                                       result)
+                           #f)))
          (option '(#\r "remove") #f #t
                  (lambda (opt name arg result arg-handler)
                    (let arg-handler ((arg arg) (result result))
-- 
2.4.3