std-iscontrol


Synopsis

(std-iscontrol <ch | int>)

Description

STD-ISCONTROL returns T if the given argument is a string of one character (length 1) or a positive integer number and the character representation is a non-graphic character; a character which is not printable in DCL dialogs. These are all characters with an ascii value below 32.

It denotes the class of chars that are not correctly printed in DCL edit_box or list_box controls. It checks for the class of non-graphic characters, also named formatting characters or control characters. In DCL control chars are not printed well.

This is useful as filter in DCL printing operations.

Example

;;; filters out all non printable chars
;;; analogous to STD-STRCASE in STDSTR.LSP
(defun DCL-PRINTABLE-STRING (s)
  (cond
    ((std-list->string
     (mapcar
      (function (lambda (ch)
        (if (std-iscontrol ch) "" ch)))
      (std-string->list s))))
    (T "")))

Arguments

ch: any valid lisp expression

Return Value

T or nil.

Side Effects

None.

Module

(std-require 'STDSTR)

Defined in STDSTR