Implemented macros in elisp compiler.

* module/language/elisp/README: Document it.
* module/language/elisp/compile-tree-il.scm: Implement defmacro and expansion.
* module/language/elisp/runtime/macro-slot.scm: New module to keep definitions.
* test-suite/Makefile.am: Add elisp-compiler.test to list of tests.
* test-suite/tests/elisp-compiler.test: Basic macro tests.

module/language/elisp/README

@@ -14,6 +14,7 @@ Already implemented:
   * lambda expressions, function calls using list notation
   * some built-ins (mainly numbers/arithmetic)
   * defconst, defvar, defun
+  * macros
 
 Especially still missing:
   * other progX forms, will be done in macros
@@ -22,7 +23,6 @@ Especially still missing:
   * catch/throw, unwind-protect
   * real elisp reader instead of Scheme's
   * set, makunbound, boundp functions
-  * macros
   * more general built-ins
   * funcall and apply functions
   * fset & friends, defalias functions
@@ -30,3 +30,5 @@ Especially still missing:
   * defsubst and inlining
   * real quoting
   * need fluids for function bindings?
+  * recursive macros
+  * anonymous macros

module/language/elisp/compile-tree-il.scm

@@ -22,6 +22,7 @@
 (define-module (language elisp compile-tree-il)
   #:use-module (language tree-il)
   #:use-module (system base pmatch)
+  #:use-module (system base compile)
   #:export (compile-tree-il))
 
 
@@ -46,6 +47,7 @@
 (define runtime '(language elisp runtime))
 (define value-slot '(language elisp runtime value-slot))
 (define function-slot '(language elisp runtime function-slot))
+(define macro-slot '(language elisp runtime macro-slot))
 
 
 ; Build a call to a primitive procedure nicely.
@@ -282,6 +284,23 @@
     (else #t)))
 
 
+; Handle macro bindings.
+
+(define (is-macro? sym)
+  (module-defined? (resolve-interface macro-slot) sym))
+
+(define (define-macro! loc sym definition)
+  (let ((resolved (resolve-module macro-slot)))
+    (if (is-macro? sym)
+      (report-error loc "macro is already defined" sym)
+      (begin
+        (module-define! resolved sym definition)
+        (module-export! resolved (list sym))))))
+
+(define (get-macro sym)
+  (module-ref (resolve-module macro-slot) sym))
+
+
 ; Compile a symbol expression.  This is a variable reference or maybe some
 ; special value like nil.
 
@@ -470,9 +489,24 @@
                               (compile-lambda loc args body))
                (make-const loc name)))))
 
+    ; Define a macro (this is done directly at compile-time!).
+    ; FIXME: Recursive macros don't work!
+    ((defmacro ,name ,args . ,body)
+     (if (not (symbol? name))
+       (error "expected symbol as macro name" name)
+       (let* ((tree-il (compile-lambda loc args body))
+              (object (compile tree-il #:from 'tree-il #:to 'value)))
+         (define-macro! loc name object)
+         (make-const loc name))))
+
     (('quote ,val)
      (make-const loc val))
 
+    ; Macro calls are simply expanded and recursively compiled.
+    ((,macro . ,args) (guard (and (symbol? macro) (is-macro? macro)))
+     (let ((expander (get-macro macro)))
+       (compile-expr (apply expander args))))
+
     ; Function calls using (function args) standard notation; here, we have to
     ; take the function value of a symbol if it is one.  It seems that functions
     ; in form of uncompiled lists are not supported in this syntax, so we don't

module/language/elisp/runtime/macro-slot.scm

@@ -0,0 +1,27 @@
+;;; Guile Emac Lisp
+
+;; Copyright (C) 2001 Free Software Foundation, Inc.
+
+;; This program 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 2, or (at your option)
+;; any later version.
+;; 
+;; This program 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 this program; see the file COPYING.  If not, write to
+;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Code:
+
+(define-module (language elisp runtime macro-slot))
+
+; This module contains the macro definitions of elisp symbols.  In contrast to
+; the other runtime modules, those are used directly during compilation, of
+; course, so not really in runtime.  But I think it fits well to the others
+; here.

test-suite/Makefile.am

@@ -32,6 +32,7 @@ SCM_TESTS = tests/alist.test			\
 	    tests/common-list.test		\
 	    tests/continuations.test		\
 	    tests/elisp.test			\
+	    tests/elisp-compiler.text		\
 	    tests/environments.test		\
 	    tests/eval.test			\
 	    tests/exceptions.test		\

test-suite/tests/elisp-compiler.test

@@ -211,6 +211,19 @@
                 (zerop a)))))
 
 
+; Macros.
+; =======
+
+(with-test-prefix/compile "Macros"
+
+  (pass-if-equal "defmacro value" 'magic-number
+    (defmacro magic-number () 42))
+
+  (pass-if-equal "macro expansion" 1
+    (progn (defmacro take-first (a b) a)
+           (take-first 1 (/ 1 0)))))
+
+
 ; Test the built-ins.
 ; ===================