Parser for elisp and use it as reader.

* module/language/elisp/parser.scm: New parser file.
* module/language/elisp/lexer.scm: Fix lexer/1 and add unquote-splicing support.
* module/language/elisp/spec.scm: Use new elisp-reader.
* module/language/elisp/README: Document we've got a reader now.
* test-suite/tests/elisp-reader.test: Test the parser.

module/language/elisp/parser.scm

@@ -0,0 +1,76 @@
+;;; 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 parser)
+  #:use-module (language elisp lexer)
+  #:use-module (language ecmascript parse-lalr)
+  #:export (read-elisp))
+
+; The parser (reader) for elisp expressions.  It is implemented using the
+; (text parse-lalr) parser generator and uses my hand-written lexer as
+; the tokenizer.
+
+
+; Build the parser itself using parse-lalr.
+
+(define elisp-parser
+  (lalr-parser (integer float symbol character string
+                paren-open paren-close square-open square-close
+                dot quote backquote unquote unquote-splicing)
+
+    ; Expressions are our main interest.
+    ; It seems the symbol we're interested for return from the parser must
+    ; come very first, so here it is.
+    (expression (integer) -> $1
+                (float) -> $1
+                (symbol) -> $1
+                (character) -> $1
+                (string) -> $1
+                (list) -> $1
+                (quotation) -> $1
+                (vector) -> $1)
+
+    ; Pairs, lists and dotted lists.
+    (partial-list (expression) -> (list $1)
+                  (expression dot expression) -> (cons $1 $3)
+                  (expression partial-list) -> (cons $1 $2))
+    (list (paren-open paren-close) -> '()
+          (paren-open dot expression paren-close) -> $3
+          (paren-open partial-list paren-close) -> $2)
+
+    ; Quotation and unquotation expressions.
+    (quotation (quote expression) -> `(quote ,$2)
+               (backquote expression) -> `(\` ,$2)
+               (unquote expression) -> `(\, ,$2)
+               (unquote-splicing expression) -> `(\,@ ,$2))
+
+    ; Vectors.
+    (vector-elements (expression) -> (list $1)
+                     (expression vector-elements) -> (cons $1 $2))
+    (vector (square-open square-close) -> (make-vector 0)
+            (square-open vector-elements square-close) -> (list->vector $2))))
+
+
+; Use the parser to define the elisp reader function.
+; We only want to read a single expression at a time, so use get-lexer/1.
+
+(define (read-elisp port)
+  (elisp-parser (get-lexer/1 port) error))