Toggle diff (528 lines)
diff --git a/Makefile.am b/Makefile.am
index 5dc04de35..8d05744bc 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -85,6 +85,7 @@ MODULES = \
guix/nar.scm \
guix/derivations.scm \
guix/grafts.scm \
+ guix/inferior.scm \
guix/gnu-maintenance.scm \
guix/self.scm \
guix/upstream.scm \
@@ -200,6 +201,7 @@ MODULES = \
guix/scripts/substitute.scm \
guix/scripts/authenticate.scm \
guix/scripts/refresh.scm \
+ guix/scripts/repl.scm \
guix/scripts/system.scm \
guix/scripts/system/search.scm \
guix/scripts/lint.scm \
@@ -355,6 +357,7 @@ SCM_TESTS = \
tests/profiles.scm \
tests/search-paths.scm \
tests/syscalls.scm \
+ tests/inferior.scm \
tests/gremlin.scm \
tests/bournish.scm \
tests/lint.scm \
diff --git a/doc/guix.texi b/doc/guix.texi
index 7ce364b0a..e93b320e8 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -166,6 +166,7 @@ Programming Interface
* Derivations:: Low-level interface to package derivations.
* The Store Monad:: Purely functional interface to the store.
* G-Expressions:: Manipulating build expressions.
+* Invoking guix repl:: Fiddling with Guix interactively.
Defining Packages
@@ -3267,6 +3268,7 @@ package definitions.
* Derivations:: Low-level interface to package derivations.
* The Store Monad:: Purely functional interface to the store.
* G-Expressions:: Manipulating build expressions.
+* Invoking guix repl:: Fiddling with Guix interactively.
@end menu
@node Defining Packages
@@ -5538,6 +5540,57 @@ corresponding to @var{obj} for @var{system}, cross-compiling for
has an associated gexp compiler, such as a @code{<package>}.
@end deffn
+@node Invoking guix repl
+@section Invoking @command{guix repl}
+
+@cindex REPL, read-eval-print loop
+The @command{guix repl} command spawns a Guile @dfn{read-eval-print loop}
+(REPL) for interactive programming (@pxref{Using Guile Interactively,,, guile,
+GNU Guile Reference Manual}). Compared to just launching the @command{guile}
+command, @command{guix repl} guarantees that all the Guix modules and all its
+dependencies are available in the search path. You can use it this way:
+
+@example
+$ guix repl
+scheme@@(guile-user)> ,use (gnu packages base)
+scheme@@(guile-user)> coreutils
+$1 = #<package coreutils@@8.29 gnu/packages/base.scm:327 3e28300>
+@end example
+
+@cindex inferiors
+In addition, @command{guix repl} implements a simple machine-readable REPL
+protocol for use by @code{(guix inferior)}, a facility to interact with
+@dfn{inferiors}, separate processes running a potentially different revision
+of Guix.
+
+The available options are as follows:
+
+@table @code
+@item --type=@var{type}
+@itemx -t @var{type}
+Start a REPL of the given @var{TYPE}, which can be one of the following:
+
+@table @code
+@item guile
+This is default, and it spawns a standard full-featured Guile REPL.
+@item machine
+Spawn a REPL that uses the machine-readable protocol. This is the protocol
+that the @code{(guix inferior)} module speaks.
+@end table
+
+@item --listen=@var{endpoint}
+By default, @command{guix repl} reads from standard input and writes to
+standard output. When this option is passed, it will instead listen for
+connections on @var{endpoint}. Here are examples of valid options:
+
+@table @code
+@item --listen=tcp:37146
+Accept connections on localhost on port 37146.
+
+@item --listen=unix:/tmp/socket
+Accept connections on the Unix-domain socket @file{/tmp/socket}.
+@end table
+@end table
@c *********************************************************************
@node Utilities
diff --git a/guix/inferior.scm b/guix/inferior.scm
new file mode 100644
index 000000000..629c2c431
--- /dev/null
+++ b/guix/inferior.scm
@@ -0,0 +1,197 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix 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 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix 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.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix inferior)
+ #:use-module (srfi srfi-9)
+ #:use-module (srfi srfi-9 gnu)
+ #:use-module (ice-9 match)
+ #:use-module (ice-9 popen)
+ #:export (inferior?
+ open-inferior
+ close-inferior
+ inferior-eval
+ inferior-object?
+
+ inferior-package?
+ inferior-package-name
+ inferior-package-version
+
+ inferior-packages
+ inferior-package-synopsis
+ inferior-package-description))
+
+;;; Commentary:
+;;;
+;;; This module provides a way to spawn Guix "inferior" processes and to talk
+;;; to them. It allows us, from one instance of Guix, to interact with
+;;; another instance of Guix coming from a different commit.
+;;;
+;;; Code:
+
+;; Inferior Guix process.
+(define-record-type <inferior>
+ (inferior pid socket version)
+ inferior?
+ (pid inferior-pid)
+ (socket inferior-socket)
+ (version inferior-version)) ;REPL protocol version
+
+(define (inferior-pipe directory command)
+ "Return an input/output pipe on the Guix instance in DIRECTORY. This runs
+'DIRECTORY/COMMAND repl' if it exists, or falls back to some other method if
+it's an old Guix."
+ (let ((pipe (with-error-to-port (%make-void-port "w")
+ (lambda ()
+ (open-pipe* OPEN_BOTH
+ (string-append directory "/" command)
+ "repl" "-t" "machine")))))
+ (if (eof-object? (peek-char pipe))
+ (begin
+ (close-pipe pipe)
+
+ ;; Older versions of Guix didn't have a 'guix repl' command, so
+ ;; emulate it.
+ (open-pipe* OPEN_BOTH "guile"
+ "-L" (string-append directory "/share/guile/site/"
+ (effective-version))
+ "-C" (string-append directory "/share/guile/site/"
+ (effective-version))
+ "-C" (string-append directory "/lib/guile/"
+ (effective-version) "/site-ccache")
+ "-c"
+ (object->string
+ `(begin
+ (primitive-load ,(search-path %load-path
+ "guix/scripts/repl.scm"))
+ ((@ (guix scripts repl) machine-repl))))))
+ pipe)))
+
+(define* (open-inferior directory #:key (command "bin/guix"))
+ "Open the inferior Guix in DIRECTORY, running 'DIRECTORY/COMMAND repl' or
+equivalent. Return #f if the inferior could not be launched."
+ (define pipe
+ (inferior-pipe directory command))
+
+ (setvbuf pipe _IOLBF)
+ (match (read pipe)
+ (('repl-version 0 rest ...)
+ (let ((result (inferior 'pipe pipe (cons 0 rest))))
+ (inferior-eval '(use-modules (guix)) result)
+ (inferior-eval '(use-modules (gnu)) result)
+ (inferior-eval '(define %package-table (make-hash-table))
+ result)
+ result))
+ (_
+ #f)))
+
+(define (close-inferior inferior)
+ "Close INFERIOR."
+ (close-pipe (inferior-socket inferior)))
+
+;; Non-self-quoting object of the inferior.
+(define-record-type <inferior-object>
+ (inferior-object address appearance)
+ inferior-object?
+ (address inferior-object-address)
+ (appearance inferior-object-appearance))
+
+(define (write-inferior-object object port)
+ (match object
+ (($ <inferior-object> _ appearance)
+ (format port "#<inferior-object ~a>" appearance))))
+
+(set-record-type-printer! <inferior-object> write-inferior-object)
+
+(define (inferior-eval exp inferior)
+ "Evaluate EXP in INFERIOR."
+ (define sexp->object
+ (match-lambda
+ (('value value)
+ value)
+ (('non-self-quoting address string)
+ (inferior-object address string))))
+
+ (write exp (inferior-socket inferior))
+ (newline (inferior-socket inferior))
+ (match (read (inferior-socket inferior))
+ (('values objects ...)
+ (apply values (map sexp->object objects)))
+ (('exception key objects ...)
+ (apply throw key (map sexp->object objects)))))
+
+
+;;;
+;;; Inferior packages.
+;;;
+
+(define-record-type <inferior-package>
+ (inferior-package inferior name version id)
+ inferior-package?
+ (inferior inferior-package-inferior)
+ (name inferior-package-name)
+ (version inferior-package-version)
+ (id inferior-package-id))
+
+(define (write-inferior-package package port)
+ (match package
+ (($ <inferior-package> _ name version)
+ (format port "#<inferior-package ~a@~a ~a>"
+ name version
+ (number->string (object-address package) 16)))))
+
+(set-record-type-printer! <inferior-package> write-inferior-package)
+
+(define (inferior-packages inferior)
+ "Return the list of packages known to INFERIOR."
+ (let ((result (inferior-eval
+ '(fold-packages (lambda (package result)
+ (let ((id (object-address package)))
+ (hashv-set! %package-table id package)
+ (cons (list (package-name package)
+ (package-version package)
+ id)
+ result)))
+ '())
+ inferior)))
+ (map (match-lambda
+ ((name version id)
+ (inferior-package inferior name version id)))
+ result)))
+
+(define (inferior-package-field package getter)
+ "Return the field of PACKAGE, an inferior package, accessed with GETTER."
+ (let ((inferior (inferior-package-inferior package))
+ (id (inferior-package-id package)))
+ (inferior-eval `(,getter (hashv-ref %package-table ,id))
+ inferior)))
+
+(define* (inferior-package-synopsis package #:key (translate? #t))
+ "Return the Texinfo synopsis of PACKAGE, an inferior package. When
+TRANSLATE? is true, translate it to the current locale's language."
+ (inferior-package-field package
+ (if translate?
+ '(compose (@ (guix ui) P_) package-synopsis)
+ 'package-synopsis)))
+
+(define* (inferior-package-description package #:key (translate? #t))
+ "Return the Texinfo description of PACKAGE, an inferior package. When
+TRANSLATE? is true, translate it to the current locale's language."
+ (inferior-package-field package
+ (if translate?
+ '(compose (@ (guix ui) P_) package-description)
+ 'package-description)))
diff --git a/guix/scripts/repl.scm b/guix/scripts/repl.scm
new file mode 100644
index 000000000..b157833a4
--- /dev/null
+++ b/guix/scripts/repl.scm
@@ -0,0 +1,199 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix 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 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix 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.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix scripts repl)
+ #:use-module (guix ui)
+ #:use-module (guix scripts)
+ #:use-module (guix utils)
+ #:use-module (guix packages)
+ #:use-module (gnu packages)
+ #:use-module (srfi srfi-1)
+ #:use-module (srfi srfi-37)
+ #:use-module (ice-9 match)
+ #:use-module (rnrs bytevectors)
+ #:autoload (system repl repl) (start-repl)
+ #:autoload (system repl server)
+ (make-tcp-server-socket make-unix-domain-server-socket)
+ #:export (machine-repl
+ guix-repl))
+
+;;; Commentary:
+;;;
+;;; This command provides a Guile REPL
+
+(define %default-options
+ `((type . guile)))
+
+(define %options
+ (list (option '(#\h "help") #f #f
+ (lambda args
+ (show-help)
+ (exit 0)))
+ (option '(#\V "version") #f #f
+ (lambda args
+ (show-version-and-exit "guix repl")))
+ (option '(#\t "type") #t #f
+ (lambda (opt name arg result)
+ (alist-cons 'type (string->symbol arg) result)))
+ (option '("listen") #t #f
+ (lambda (opt name arg result)
+ (alist-cons 'listen arg result)))))
+
+
+(define (show-help)
+ (display (G_ "Usage: guix repl [OPTIONS...]
+Start a Guile REPL in the Guix execution environment.\n"))
+ (display (G_ "
+ -t, --type=TYPE start a REPL of the given TYPE"))
+ (newline)
+ (display (G_ "
+ -h, --help display this help and exit"))
+ (display (G_ "
+ -V, --version display version information and exit"))
+ (newline)
+ (show-bug-report-information))
+
+(define (self-quoting? x)
+ "Return #t if X is self-quoting."
+ (letrec-syntax ((one-of (syntax-rules ()
+ ((_) #f)
+ ((_ pred rest ...)
+ (or (pred x)
+ (one-of rest ...))))))
+ (one-of symbol? string? pair? null? vector?
+ bytevector? number? boolean?)))
+
+(define user-module
+ ;; Module where we execute user code.
+ (let ((module (resolve-module '(guix-user) #f #f #:ensure #t)))
+ (beautify-user-module! module)
+ module))
+
+(define* (machine-repl #:optional
+ (input (current-input-port))
+ (output (current-output-port)))
+ "Run a machine-usable REPL over ports INPUT and OUTPUT.
+
+The protocol of this REPL is meant to be machine-readable and provides proper
+support to represent multiple-value returns, exceptions, objects that lack a
+read syntax, and so on. As such it is more convenient and robust than parsing
+Guile's REPL prompt."
+ (define (value->sexp value)
+ (if (self-quoting? value)
+ `(value ,value)
+ `(non-self-quoting ,(object-address value)
+ ,(object->string value))))
+
+ (write `(repl-version 0 0) output)
+ (newline output)
+ (force-output output)
+
+ (let loop ()
+ (match (read input)
+ ((? eof-object?) #t)
+ (exp
+ (catch #t
+ (lambda ()
+ (let ((results (call-with-values
+ (lambda ()
+
+ (primitive-eval exp))
+ list)))
+ (write `(values ,@(map value->sexp results))
+ output)
+ (newline output)
+ (force-output output)))
+ (lambda (key . args)
+ (write `(exception ,key ,@(map value->sexp args)))
+ (newline output)
+ (force-output output)))
+ (loop)))))
+
+(define (call-with-connection spec thunk)
+ "Dynamically-bind the current input and output ports according to SPEC and
+call THUNK."
+ (if (not spec)
+ (thunk)
+
+ ;; Note: the "PROTO:" prefix in SPEC is here so that we can eventually
+ ;; parse things like "fd:123" in a non-ambiguous way.
+ (match (string-index spec #\:)
+ (#f
+ (leave (G_ "~A: invalid listen specification~%") spec))
+ (index
+ (let ((protocol (string-take spec index))
+ (address (string-drop spec (+ index 1))))
+ (define socket
+ (match protocol
+ ("tcp"
+ (make-tcp-server-socket #:port (string->number address)))
+ ("unix"
+ (make-unix-domain-server-socket #:path address))
+ (_
+ (leave (G_ "~A: unsupported protocol family~%")
+ protocol))))
+
+ (listen socket 10)
+ (let loop ()
+ (match (accept socket)
+ ((connection . address)
+ (if (= AF_UNIX (sockaddr:fam address))
+ (info (G_ "accepted connection~%"))
+ (info (G_ "accepted connection from ~a~%")
+ (inet-ntop (sockaddr:fam address)
+ (sockaddr:addr address))))
+ (dynamic-wind
+ (const #t)
+ (lambda ()
+ (parameterize ((current-input-port connection)
+ (current-output-port connection))
+ (thunk)))
+ (lambda ()
+ (false-if-exception (close-port connection))
+ (info (G_ "connection closed~%"))))))
+ (loop)))))))
+
+
+(define (guix-repl . args)
+ (define opts
+ ;; Return the list of package names.
+ (args-fold* args %options
+ (lambda (opt name arg result)
+ (leave (G_ "~A: unrecognized option~%") name))
+ (lambda (arg result)
+ (leave (G_ "~A: extraneous argument~%") arg))
+ %default-options))
+
+ (with-error-handling
+ (let ((type (assoc-ref opts 'type)))
+ (call-with-connection (assoc-ref opts 'listen)
+ (lambda ()
+ (case type
+ ((guile)
+ (save-module-excursion
+ (lambda ()
+ (set-current-module user-module)
+ (start-repl))))
+ ((machine)
+ (machine-repl))
+ (else
+ (leave (G_ "~a: unknown type of REPL~%") type))))))))
+
+;; Local Variables:
+;; eval: (put 'call-with-connection 'scheme-indent-function 1)
+;; End:
diff --git a/tests/inferior.scm b/tests/inferior.scm
new file mode 100644
index 000000000..5e0f8ae66
--- /dev/null
+++ b/tests/inferior.scm
@@ -0,0 +1,69 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix 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 3 of the License,
