Function: ebnf-eliminate-empty-rules

ebnf-eliminate-empty-rules is an autoloaded and byte-compiled function defined in ebnf-otz.el.gz.

Signature

(ebnf-eliminate-empty-rules SYNTAX-LIST)

Documentation

Eliminate empty rules.

Source Code

;; Defined in /usr/src/emacs/lisp/progmodes/ebnf-otz.el.gz
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Eliminate empty rules


(defun ebnf-eliminate-empty-rules (syntax-list)
  "Eliminate empty rules."
  (while ebnf-empty-rule-list
    (let ((ebnf-total (length syntax-list))
	  (ebnf-nprod 0)
	  (prod-list syntax-list)
	  new-list before)
      (while prod-list
	(ebnf-message-info "Eliminating empty rules")
	(let ((rule (car prod-list)))
	  ;; if any non-terminal pertains to ebnf-empty-rule-list
	  ;; then eliminate non-terminal from rule
	  (if (ebnf-eliminate-empty rule)
	      (setq before prod-list)
	    ;; eliminate empty rule from syntax-list
	    (setq new-list (cons (ebnf-node-name rule) new-list))
	    (if before
		(setcdr before (cdr prod-list))
	      (setq syntax-list (cdr syntax-list)))))
	(setq prod-list (cdr prod-list)))
      (setq ebnf-empty-rule-list new-list)))
  syntax-list)