bournish: Allow compilation of multiple expressions.

* guix/build/bournish.scm (%bournish-language): Add a joiner to SCHEME.
Compile only to Scheme.
* tests/bournish.scm: New file.
* Makefile.am (SCM_TESTS): Add it.

Makefile.am

@@ -248,6 +248,7 @@ SCM_TESTS =					\
   tests/profiles.scm				\
   tests/syscalls.scm				\
   tests/gremlin.scm				\
+  tests/bournish.scm				\
   tests/lint.scm				\
   tests/publish.scm				\
   tests/scripts.scm				\

guix/build/bournish.scm

@@ -149,11 +149,24 @@ code as an sexp."
 
 (define %bournish-language
   (let ((scheme (lookup-language 'scheme)))
+    ;; XXX: The 'scheme' language lacks a "joiner", so we add one here.  This
+    ;; allows us to have 'read-bournish' read one shell statement at a time
+    ;; instead of having to read until EOF.
+    (set! (language-joiner scheme)
+      (lambda (exps env)
+        (match exps
+          (()   '(begin))
+          ((exp) exp)
+          (_    `(begin ,@exps)))))
+
     (make-language #:name 'bournish
                    #:title "Bournish"
+
+                   ;; The reader does all the heavy lifting.
                    #:reader read-bournish
-                   #:compilers (language-compilers scheme)
-                   #:decompilers (language-decompilers scheme)
+                   #:compilers `((scheme . ,(lambda (exp env options)
+                                              (values exp env env))))
+                   #:decompilers '()
                    #:evaluator (language-evaluator scheme)
                    #:printer (language-printer scheme)
                    #:make-default-environment

tests/bournish.scm

@@ -0,0 +1,42 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2016 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 (test-bournish)
+  #:use-module (guix build bournish)
+  #:use-module (system base compile)
+  #:use-module (system base language)
+  #:use-module (srfi srfi-64))
+
+
+(test-begin "bournish")
+
+(test-equal "single statement"
+  '(chdir "/foo")
+  (read-and-compile (open-input-string "cd /foo")
+                    #:from %bournish-language #:to 'scheme))
+
+(test-equal "multiple statements"
+  '(begin
+     (chdir "/foo")
+     (getcwd)
+     ((@@ (guix build bournish) ls-command-implementation)))
+  (read-and-compile (open-input-string "cd /foo\npwd\nls")
+                    #:from %bournish-language #:to 'scheme))
+
+(test-end "bournish")
+