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Parse-utils

Vl-match-token

Compatible with seq. Consume and return a token of exactly some particular type, or cause an error if the desired kind of token is not at the start of the input stream.

Signature
(vl-match-token type &key (function '__function__) (tokstream 'tokstream)) → (mv errmsg? token new-tokstream)
Arguments: type — Kind of token to match.
Guard (vl-tokentype-p type).; function — Guard (symbolp function).
Returns: errmsg? — Type (and (iff errmsg? (not (vl-is-token? type))) (iff (vl-warning-p errmsg?) errmsg?)) .; token — Type (vl-token-p token), given (vl-is-token? type).

Definitions and Theorems

Function: vl-match-token-fn

(defun vl-match-token-fn (type function tokstream)
 (declare (xargs :stobjs (tokstream)))
 (declare (xargs :guard (and (vl-tokentype-p type)
                             (symbolp function))))
 (let ((__function__ 'vl-match-token))
  (declare (ignorable __function__))
  (b*
   ((tokens (vl-tokstream->tokens))
    ((when (atom tokens))
     (vl-parse-error "Unexpected EOF."
                     :function function))
    (token1 (car tokens))
    ((unless (eq type (vl-token->type token1)))
     (mv (make-vl-warning
              :type :vl-parse-error
              :msg "Parse error at ~a0: expected ~s1 but found ~s2."
              :args (list (vl-token->loc (car tokens))
                          type (vl-token->type token1))
              :fatalp t
              :fn function)
         nil tokstream))
    (tokstream (vl-tokstream-pop)))
   (mv nil token1 tokstream))))

Theorem: return-type-of-vl-match-token.errmsg?

(defthm return-type-of-vl-match-token.errmsg?
  (b* (((mv ?errmsg? ?token ?new-tokstream)
        (vl-match-token-fn type function tokstream)))
    (and (iff errmsg? (not (vl-is-token? type)))
         (iff (vl-warning-p errmsg?) errmsg?)))
  :rule-classes :rewrite)

Theorem: vl-token-p-of-vl-match-token.token

(defthm vl-token-p-of-vl-match-token.token
  (implies (vl-is-token? type)
           (b* (((mv ?errmsg? ?token ?new-tokstream)
                 (vl-match-token-fn type function tokstream)))
             (vl-token-p token)))
  :rule-classes :rewrite)

Theorem: vl-match-token-fails-gracefully

(defthm vl-match-token-fails-gracefully
  (implies (not (vl-is-token? type))
           (equal (mv-nth 1 (vl-match-token type))
                  nil)))

Theorem: vl-match-token-under-iff

(defthm vl-match-token-under-iff
  (iff (mv-nth 1 (vl-match-token type))
       (vl-is-token? type)))

Theorem: vl-token->type-of-vl-match-token

(defthm vl-token->type-of-vl-match-token
  (implies (vl-is-token? type)
           (equal (vl-token->type (mv-nth 1 (vl-match-token type)))
                  type)))

Theorem: vl-match-token-count-strong-on-value

(defthm vl-match-token-count-strong-on-value
  (and (<= (vl-tokstream-measure
                :tokstream (mv-nth 2 (vl-match-token type)))
           (vl-tokstream-measure))
       (implies (mv-nth 1 (vl-match-token type))
                (< (vl-tokstream-measure
                        :tokstream (mv-nth 2 (vl-match-token type)))
                   (vl-tokstream-measure))))
  :rule-classes ((:rewrite) (:linear)))

Theorem: equal-of-vl-match-token-count

(defthm equal-of-vl-match-token-count
  (equal (equal (vl-tokstream-measure
                     :tokstream (mv-nth 2 (vl-match-token type)))
                (vl-tokstream-measure))
         (if (mv-nth 0 (vl-match-token type))
             t
           nil)))