• Top
  • Documentation
  • Books
  • Boolean-reasoning
  • Projects
  • Debugging
  • Std
    • Std/lists
    • Std/alists
    • Obags
    • Std/util
    • Std/strings
      • Pretty-printing
      • Printtree
      • Base64
      • Charset-p
      • Strtok!
      • Cases
      • Concatenation
      • Html-encoding
      • Character-kinds
      • Substrings
      • Strtok
      • Equivalences
      • Url-encoding
      • Lines
      • Explode-implode-equalities
      • Ordering
      • Numbers
        • Decimal
        • Hex
        • Octal
          • Parse-octal-from-string
          • Parse-octal-from-charlist
          • Nat-to-oct-chars
          • Oct-digit-chars-value
          • Oct-digit-char-p
          • Take-leading-oct-digit-chars
          • Oct-digit-char-value
          • Oct-digit-char-list*p
          • Oct-digit-char-listp
          • Skip-leading-octal-digits
          • Oct-digit-string-p
          • Nat-to-oct-string
          • Strval8
          • Nat-to-oct-string-list
          • Revappend-nat-to-oct-chars
          • Nonzero-oct-digit-char-p
          • Nat-to-oct-string-size
          • Octal-digit-to-char
        • Binary
      • Pad-trim
      • Coercion
      • Std/strings/digit-to-char
      • Substitution
      • Symbols
    • Std/io
    • Std/osets
    • Std/basic
    • Std/system
    • Std/typed-lists
    • Std/bitsets
    • Std/testing
    • Std/typed-alists
    • Std/stobjs
  • Proof-automation
  • Macro-libraries
  • ACL2
  • Interfacing-tools
  • Hardware-verification
  • Software-verification
  • Math
  • Testing-utilities

• Octal

Strval8

Interpret a string as a octal number.

Signature

(strval8 x) → value?

Arguments

x — Guard (stringp x).

Returns

value? — Type (or (natp value?) (not value?)).

For example, (strval8 "17") is 15. If the string is empty or has any non octal digit characters (0-7), we return nil.

Definitions and Theorems

Function: strval8

(defun strval8 (x)
  (declare (xargs :guard (stringp x)))
  (declare (type string x))
  (declare (xargs :split-types t))
  (let ((acl2::__function__ 'strval8))
    (declare (ignorable acl2::__function__))
    (mbe :logic
         (let ((chars (explode x)))
           (and (consp chars)
                (oct-digit-char-list*p chars)
                (oct-digit-chars-value chars)))
         :exec
         (b* (((the unsigned-byte xl) (length x))
              ((mv (the unsigned-byte val)
                   (the unsigned-byte len))
               (parse-octal-from-string x 0 0 0 xl)))
           (and (not (eql 0 len))
                (eql len xl)
                val)))))

Theorem: return-type-of-strval8

(defthm return-type-of-strval8
  (b* ((value? (strval8 x)))
    (or (natp value?) (not value?)))
  :rule-classes :type-prescription)

Theorem: istreqv-implies-equal-strval8-1

(defthm istreqv-implies-equal-strval8-1
  (implies (istreqv x x-equiv)
           (equal (strval8 x) (strval8 x-equiv)))
  :rule-classes (:congruence))