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Syntax-abstraction

Abs-ascii-character-escape

Abstract an ascii-character-escape to a Leo character.

Signature
(abs-ascii-character-escape tree) → char
Arguments: tree — Guard (abnf::treep tree).
Returns: char — Type (char-resultp char).

Definitions and Theorems

Function: abs-ascii-character-escape

(defun abs-ascii-character-escape (tree)
 (declare (xargs :guard (abnf::treep tree)))
 (let ((__function__ 'abs-ascii-character-escape))
   (declare (ignorable __function__))
   (b* (((okf (abnf::tree-list-tuple3 sub))
         (abnf::check-tree-nonleaf-3 tree "ascii-character-escape"))
        ((okf x-tree)
         (abnf::check-tree-list-1 sub.1st))
        ((okf &)
         (abnf::check-tree-schars x-tree "\\x"))
        ((okf oct-tree)
         (abnf::check-tree-list-1 sub.2nd))
        ((okf hi)
         (abs-octal-digit-to-nat oct-tree))
        ((okf hex-tree)
         (abnf::check-tree-list-1 sub.3rd))
        ((okf lo)
         (abs-hexadecimal-digit-to-nat hex-tree)))
     (char (+ (* 16 hi) lo)))))

Theorem: char-resultp-of-abs-ascii-character-escape

(defthm char-resultp-of-abs-ascii-character-escape
  (b* ((char (abs-ascii-character-escape tree)))
    (char-resultp char))
  :rule-classes :rewrite)

Theorem: abs-ascii-character-escape-of-tree-fix-tree

(defthm abs-ascii-character-escape-of-tree-fix-tree
  (equal (abs-ascii-character-escape (abnf::tree-fix tree))
         (abs-ascii-character-escape tree)))

Theorem: abs-ascii-character-escape-tree-equiv-congruence-on-tree

(defthm abs-ascii-character-escape-tree-equiv-congruence-on-tree
  (implies (abnf::tree-equiv tree tree-equiv)
           (equal (abs-ascii-character-escape tree)
                  (abs-ascii-character-escape tree-equiv)))
  :rule-classes :congruence)