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Printer

Print-h-char

Print a character usable in header names in angle brackets.

Signature
(print-h-char hchar pstate) → new-pstate
Arguments: hchar — Guard (h-char-p hchar).; pstate — Guard (pristatep pstate).
Returns: new-pstate — Type (pristatep new-pstate).

The abstract syntax puts no limitation on the character (code), but here we check that it satisfies the requirements in the concrete syntax. It must be a character in the grammar, and in addition it must not be a greater-than or a new-line character. The latter check encompasses not only line feed, but also carriage return: recall that both are allowed in our grammar, and that we allow three kinds of new-line characters (line feed alone, carriage return alone, or line feed followed by carriage return).

Definitions and Theorems

Function: print-h-char

(defun print-h-char (hchar pstate)
 (declare (xargs :guard (and (h-char-p hchar)
                             (pristatep pstate))))
 (let ((__function__ 'print-h-char))
  (declare (ignorable __function__))
  (b*
   ((code (h-char->char hchar))
    ((unless (and (grammar-character-p code)
                  (not (= code (char-code #\<)))
                  (not (= code 10))
                  (not (= code 13))))
     (raise
      "Misusage error: ~
                the character code ~x0 is disallowed ~
                in a header in between angle brackets."
      code)
     (pristate-fix pstate)))
   (print-char code pstate))))

Theorem: pristatep-of-print-h-char

(defthm pristatep-of-print-h-char
  (b* ((new-pstate (print-h-char hchar pstate)))
    (pristatep new-pstate))
  :rule-classes :rewrite)

Theorem: pristate->gcc-of-print-h-char

(defthm pristate->gcc-of-print-h-char
  (b* ((?new-pstate (print-h-char hchar pstate)))
    (equal (pristate->gcc new-pstate)
           (pristate->gcc pstate))))

Theorem: print-h-char-of-h-char-fix-hchar

(defthm print-h-char-of-h-char-fix-hchar
  (equal (print-h-char (h-char-fix hchar) pstate)
         (print-h-char hchar pstate)))

Theorem: print-h-char-h-char-equiv-congruence-on-hchar

(defthm print-h-char-h-char-equiv-congruence-on-hchar
  (implies (h-char-equiv hchar hchar-equiv)
           (equal (print-h-char hchar pstate)
                  (print-h-char hchar-equiv pstate)))
  :rule-classes :congruence)

Theorem: print-h-char-of-pristate-fix-pstate

(defthm print-h-char-of-pristate-fix-pstate
  (equal (print-h-char hchar (pristate-fix pstate))
         (print-h-char hchar pstate)))

Theorem: print-h-char-pristate-equiv-congruence-on-pstate

(defthm print-h-char-pristate-equiv-congruence-on-pstate
  (implies (pristate-equiv pstate pstate-equiv)
           (equal (print-h-char hchar pstate)
                  (print-h-char hchar pstate-equiv)))
  :rule-classes :congruence)