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Acre-internals

Parse-charset-atom

Signature
(parse-charset-atom x index) → (mv err char new-index)
Arguments: x — Guard (stringp x).; index — Guard (natp index).
Returns: err — Type (acl2::maybe-stringp err).; char — Type (characterp char).; new-index — Type (natp new-index).

Definitions and Theorems

Function: parse-charset-atom

(defun parse-charset-atom (x index)
  (declare (xargs :guard (and (stringp x) (natp index))))
  (declare (xargs :guard (<= index (strlen x))))
  (let ((__function__ 'parse-charset-atom))
    (declare (ignorable __function__))
    (b* ((x (lstrfix x))
         (index (lnfix index))
         ((unless (< index (strlen x)))
          (mv "String ended inside charset"
              (code-char 0)
              index))
         (char1 (char x index))
         (index (+ 1 index))
         ((when (eql char1 #\]))
          (mv "End of charset" (code-char 0)
              index))
         ((unless (eql char1 #\\))
          (mv nil char1 index))
         ((unless (< index (strlen x)))
          (mv "String ended inside charset"
              (code-char 0)
              index))
         (char2 (char x index))
         (index (+ 1 index)))
      (case char2
        ((#\\ #\] #\-) (mv nil char2 index))
        (#\n (mv nil #\Newline index))
        (#\t (mv nil #\Tab index))
        (#\r (mv nil #\Return index))
        (#\f (mv nil #\Page index))
        (#\o (parse-octal-charcode x index))
        (#\x (parse-hex-charcode x index))
        (t (mv (str::cat "Unrecognized escape sequence in charset: "
                         (coerce (list char1 char2) 'string))
               (code-char 0)
               index))))))

Theorem: maybe-stringp-of-parse-charset-atom.err

(defthm maybe-stringp-of-parse-charset-atom.err
  (b* (((mv ?err common-lisp::?char ?new-index)
        (parse-charset-atom x index)))
    (acl2::maybe-stringp err))
  :rule-classes :type-prescription)

Theorem: characterp-of-parse-charset-atom.char

(defthm characterp-of-parse-charset-atom.char
  (b* (((mv ?err common-lisp::?char ?new-index)
        (parse-charset-atom x index)))
    (characterp char))
  :rule-classes :rewrite)

Theorem: natp-of-parse-charset-atom.new-index

(defthm natp-of-parse-charset-atom.new-index
  (b* (((mv ?err common-lisp::?char ?new-index)
        (parse-charset-atom x index)))
    (natp new-index))
  :rule-classes :type-prescription)

Theorem: new-index-of-parse-charset-atom

(defthm new-index-of-parse-charset-atom
  (b* (((mv ?err common-lisp::?char ?new-index)
        (parse-charset-atom x index)))
    (<= (nfix index) new-index))
  :rule-classes :linear)

Theorem: new-index-of-parse-charset-atom-strong

(defthm new-index-of-parse-charset-atom-strong
  (b* (((mv ?err common-lisp::?char ?new-index)
        (parse-charset-atom x index)))
    (implies (not err)
             (< (nfix index) new-index)))
  :rule-classes :linear)

Theorem: new-index-of-parse-charset-atom-less-than-length

(defthm new-index-of-parse-charset-atom-less-than-length
  (b* (((mv ?err common-lisp::?char ?new-index)
        (parse-charset-atom x index)))
    (implies (<= (nfix index)
                 (len (acl2::explode x)))
             (<= new-index (len (acl2::explode x)))))
  :rule-classes :linear)

Theorem: parse-charset-atom-of-str-fix-x

(defthm parse-charset-atom-of-str-fix-x
  (equal (parse-charset-atom (acl2::str-fix x)
                             index)
         (parse-charset-atom x index)))

Theorem: parse-charset-atom-streqv-congruence-on-x

(defthm parse-charset-atom-streqv-congruence-on-x
  (implies (acl2::streqv x x-equiv)
           (equal (parse-charset-atom x index)
                  (parse-charset-atom x-equiv index)))
  :rule-classes :congruence)

Theorem: parse-charset-atom-of-nfix-index

(defthm parse-charset-atom-of-nfix-index
  (equal (parse-charset-atom x (nfix index))
         (parse-charset-atom x index)))

Theorem: parse-charset-atom-nat-equiv-congruence-on-index

(defthm parse-charset-atom-nat-equiv-congruence-on-index
  (implies (acl2::nat-equiv index index-equiv)
           (equal (parse-charset-atom x index)
                  (parse-charset-atom x index-equiv)))
  :rule-classes :congruence)