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• Example-lexer

Lex-id/keyword

Match identifier characters to create an :id or :keyword token, as appropriate.

Signature

(lex-id/keyword sin) → (mv tok sin)

Arguments

sin — The sin stobj.

Returns

tok — The id/keyword token taken from the start of the input stream, or nil if the input stream does not start with some valid identifier or keyword.
    Type (equal (token-p tok) (if tok t nil)).

sin — The remaining input stream, with the leading token removed.

Definitions and Theorems

Function: lex-id/keyword

(defun lex-id/keyword (sin)
       (declare (xargs :stobjs (sin)))
       (declare (xargs :guard t))
       (let ((__function__ 'lex-id/keyword))
            (declare (ignorable __function__))
            (b* (((when (sin-endp sin)) (mv nil sin))
                 (car (sin-car sin))
                 ((unless (char-in-charset-p car (letter-chars)))
                  (mv nil sin))
                 ((mv match sin)
                  (sin-match-charset* (idtail-chars) sin))
                 ((when (or (equal match "void")
                            (equal match "int")
                            (equal match "float")))
                  (mv (make-token :type :keyword :text match)
                      sin)))
                (mv (make-token :type :id :text match)
                    sin))))

Theorem: return-type-of-lex-id/keyword.tok

(defthm return-type-of-lex-id/keyword.tok
        (b* (((mv ?tok ?sin) (lex-id/keyword sin)))
            (equal (token-p tok) (if tok t nil)))
        :rule-classes :rewrite)

Theorem: lex-id/keyword-progress-weak

(defthm lex-id/keyword-progress-weak
        (mv-let (tok new-sin)
                (lex-id/keyword sin)
                (declare (ignorable tok new-sin))
                (<= (len (strin-left new-sin))
                    (len (strin-left sin))))
        :rule-classes ((:rewrite) (:linear)))

Theorem: lex-id/keyword-progress-strong

(defthm lex-id/keyword-progress-strong
        (mv-let (tok new-sin)
                (lex-id/keyword sin)
                (declare (ignorable tok new-sin))
                (implies tok
                         (< (len (strin-left new-sin))
                            (len (strin-left sin)))))
        :rule-classes ((:rewrite) (:linear)))

Theorem: lex-id/keyword-reconstruction

(defthm lex-id/keyword-reconstruction
        (b* (((mv tok new-sin) (lex-id/keyword sin)))
            (implies tok
                     (equal (append (explode (token->text tok))
                                    (strin-left new-sin))
                            (strin-left sin)))))