nyacc: removed start from lalr-spec -- not needed

module/nyacc/export.scm

@@ -1,6 +1,6 @@
 ;;; nyacc/export.scm
 ;;;
-;;; Copyright (C) 2015 Matthew R. Wette
+;;; Copyright (C) 2015,2017 Matthew R. Wette
 ;;;
 ;;; This library is free software; you can redistribute it and/or
 ;;; modify it under the terms of the GNU Lesser General Public
@@ -20,7 +20,7 @@
 	    lalr->guile
 	    c-char token->bison elt->bison
 	    )
-  #:use-module ((nyacc lalr) #:select (find-terminal pp-rule))
+  #:use-module ((nyacc lalr) #:select (find-terminal pp-rule lalr-start))
   #:use-module (nyacc lex)
   #:use-module (nyacc util)
   #:use-module ((srfi srfi-1) #:select (fold))
@@ -130,7 +130,7 @@
     ;; Don't compact tables.
     (fmt port "%define lr.default-reduction accepting\n")
     ;; Provide start symbol.
-    (fmt port "%start ~A\n%%\n" (elt->bison (assq-ref spec 'start) terms))
+    (fmt port "%start ~A\n%%\n" (elt->bison (lalr-start spec) terms))
     ;;
     (do ((i 1 (1+ i))) ((= i nrule))
       (let* ((lhs (vector-ref lhs-v i)) (rhs (vector-ref rhs-v i)))

module/nyacc/lalr.scm

@@ -29,7 +29,7 @@
   #:export-syntax (lalr-spec)
   #:export (*nyacc-version*
 	    make-lalr-machine compact-machine hashify-machine 
-	    lalr-match-table
+	    lalr-start lalr-match-table
 	    restart-spec add-recovery-logic!
 	    pp-lalr-notice pp-lalr-grammar pp-lalr-machine
 	    write-lalr-actions write-lalr-tables
@@ -508,12 +508,12 @@
 	       ;; Put most referenced items first, but keep start and rhs-v at
 	       ;; top so that if we want to restart (see restart-spec) we can
 	       ;; reuse the tail here.
-	       (cons 'start start-symbol)
+	       ;;(cons 'start start-symbol) ; use lalr-start, aka rhs-v[0][0]
 	       (cons 'rhs-v (map-attr->vector al 'rhs))
 	       ;;
 	       (cons 'restart-tail #t)	; see @code{restart-spec} below
-	       (cons 'non-terms nl)
 	       (cons 'lhs-v (list->vector (reverse ll)))
+	       (cons 'non-terms nl)
 	       (cons 'terminals tl)
 	       (cons 'attr (list
 			    (cons 'expect (or (assq-ref tree 'expect) 0))
@@ -522,7 +522,7 @@
 	       (cons 'assc (assq-ref pna 'assc))
 	       (cons 'prp-v (map-attr->vector al 'prec)) ; per-rule precedence
 	       (cons 'act-v (map-attr->vector al 'act))
-	       (cons 'ref-v (map-attr->vector al 'ref))
+	       (cons 'ref-v (map-attr->vector al 'ref)) ; action references
 	       (cons 'err-l err-l)
 	       ))))))))
   
@@ -535,14 +535,20 @@
 ;; vector of vector of right-hand side symbols.
 (define *lalr-core* (make-fluid #f))
 
+;; @deffn {Procedure} lalr-start spec => symbol
+;; Return the start symbol for the grammar.
+;; @end deffn
+(define (lalr-start spec)
+  (vector-ref (vector-ref (assq-ref spec 'rhs-v) 0) 0))
+
 ;; This record holds the minimum data from the grammar needed to build the
 ;; machine from the grammar specification.
 (define-record-type lalr-core-type
-  (make-lalr-core non-terms terminals start lhs-v rhs-v eps-l)
+  ;;(make-lalr-core non-terms terminals start lhs-v rhs-v eps-l)
+  (make-lalr-core non-terms terminals lhs-v rhs-v eps-l)
   lalr-core-type?
   (non-terms core-non-terms)	      ; list of non-terminals
   (terminals core-terminals)	      ; list of non-terminals
-  (start core-start)		      ; start non-terminal
   (lhs-v core-lhs-v)		      ; vec of left hand sides
   (rhs-v core-rhs-v)		      ; vec of right hand sides
   (eps-l core-eps-l))		      ; non-terms w/ eps prod's
@@ -551,7 +557,6 @@
 (define (make-core spec)
   (make-lalr-core (assq-ref spec 'non-terms)
 		  (assq-ref spec 'terminals)
-		  (assq-ref spec 'start)
 		  (assq-ref spec 'lhs-v)
 		  (assq-ref spec 'rhs-v)
 		  '()))
@@ -561,10 +566,9 @@
 (define (make-core/extras spec)
   (let ((non-terms (assq-ref spec 'non-terms))
 	(terminals (assq-ref spec 'terminals))
-	(start (assq-ref spec 'start))
 	(lhs-v (assq-ref spec 'lhs-v))
 	(rhs-v (assq-ref spec 'rhs-v)))
-    (make-lalr-core non-terms terminals start lhs-v rhs-v
+    (make-lalr-core non-terms terminals lhs-v rhs-v
 		    (find-eps non-terms lhs-v rhs-v))))
 
 
@@ -1532,9 +1536,9 @@
 ;;   len-v - rule lengths
 ;;   rto-v - hashed lhs symbols (rto = reduce to)
 ;; to print itemsets need:
-;;   kis-v - itemsets
 ;;   lhs-v - left hand sides
 ;;   rhs-v - right hand sides
+;;   kis-v - itemsets
 ;;   pat-v - action table
 
 ;; @deffn restart-spec [spec|mach] start => spec
@@ -1545,8 +1549,7 @@
 (define (restart-spec spec start)
   (let* ((rhs-v (vector-copy (assq-ref spec 'rhs-v))))
     (vector-set! rhs-v 0 (vector start))
-    (cons* (cons 'start start)
-	   (cons 'rhs-v rhs-v)
+    (cons* (cons 'rhs-v rhs-v)
 	   (member '(restart-tail . #t) spec))))
 
 ;; @deffn make-lalr-machine spec => pgen