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Example-lexer

Lex-main

Wrapper: lex the entire input stream or fail with a good error message.

Signature
(lex-main sin) → (mv errmsg tokens sin)
Arguments: sin — The sin stobj.
Returns: errmsg — nil on success, or a good error message (as a string) on failure.
Type (or (stringp errmsg) (not errmsg)).; tokens — Type (tokenlist-p tokens).; sin — Empty input stream on success, or the remaining part of the input stream on failure.

Definitions and Theorems

Function: lex-main

(defun lex-main (sin)
  (declare (xargs :stobjs (sin)))
  (declare (xargs :guard t))
  (let ((__function__ 'lex-main))
    (declare (ignorable __function__))
    (b* (((mv okp tokens sin) (lex* sin))
         ((when okp) (mv nil tokens sin))
         (errmsg (cat (sin-file sin)
                      ":" (natstr (sin-line sin))
                      ":" (natstr (sin-col sin))
                      ": syntax error near: "
                      (sin-firstn (min 20 (sin-len sin)) sin)
                      (newline-string))))
      (mv errmsg tokens sin))))

Theorem: return-type-of-lex-main.errmsg

(defthm return-type-of-lex-main.errmsg
  (b* (((mv ?errmsg ?tokens ?sin)
        (lex-main sin)))
    (or (stringp errmsg) (not errmsg)))
  :rule-classes :type-prescription)

Theorem: tokenlist-p-of-lex-main.tokens

(defthm tokenlist-p-of-lex-main.tokens
  (b* (((mv ?errmsg ?tokens ?sin)
        (lex-main sin)))
    (tokenlist-p tokens))
  :rule-classes :rewrite)

Theorem: tokenlist-all-text-of-lex-main

(defthm tokenlist-all-text-of-lex-main
  (b* (((mv errmsg tokens ?new-sin)
        (lex-main sin)))
    (implies (not errmsg)
             (equal (tokenlist-all-text tokens)
                    (implode (strin-left sin))))))