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ANSI Common Lisp 22 Printer 22.4 Dictionary of Printer
22.4.5 pprint-fill, pprint-linear, pprint-tabular |
Function |
- Syntax:
-
pprint-fill
stream object &optional colon-p at-sign-p
nil
pprint-linear
stream object &optional colon-p at-sign-p
nil
pprint-tabular
stream object &optional colon-p at-sign-p tabsize
nil
- Arguments and Values:
-
stream - an output stream designator.
object - an object.
colon-p - a generalized boolean.
The default is true.
at-sign-p - a generalized boolean.
The default is implementation-dependent.
tabsize - a non-negative integer.
The default is 16.
- Description:
-
The functions pprint-fill, pprint-linear, and
pprint-tabular specify particular ways of pretty printing
a list to stream.
Each function prints parentheses around the output if and only
if colon-p is true.
Each function ignores its at-sign-p argument.
(Both arguments are included even though only one is needed
so that these functions can be used via ~/.../
and as set-pprint-dispatch functions, as well as directly.)
Each function handles abbreviation and the detection of circularity
and sharing correctly, and uses write to print object
when it is a non-list.
If object is a list and
if the value of *print-pretty* is false,
each of these functions prints object
using a minimum of whitespace,
as described in Section 22.1.3.5 Printing Lists and Conses.
Otherwise (if object is a list and
if the value of *print-pretty* is true):
- Examples:
-
Evaluating the following with a line length of 25 produces the output shown.
(progn (princ "Roads ")
(pprint-tabular *standard-output* '(elm main maple center) nil nil 8))
Roads ELM MAIN
MAPLE CENTER
- Side Effects:
-
Performs output to the indicated stream.
- Affected By:
-
The cursor position on the indicated stream, if it can be determined.
- Notes:
-
The function pprint-tabular could be defined as follows:
(defun pprint-tabular (s list &optional (colon-p t) at-sign-p (tabsize nil))
(declare (ignore at-sign-p))
(when (null tabsize) (setq tabsize 16))
(pprint-logical-block (s list :prefix (if colon-p "(" "")
:suffix (if colon-p ")" ""))
(pprint-exit-if-list-exhausted)
(loop (write (pprint-pop) :stream s)
(pprint-exit-if-list-exhausted)
(write-char #\Space s)
(pprint-tab :section-relative 0 tabsize s)
(pprint-newline :fill s))))
Note that it would have been inconvenient to specify this function
using format, because of the need to pass its tabsize argument
through to a ~:T format directive nested within an iteration over a list.
- Allegro CL Implementation Details:
-
None.
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