The value of this variable is the default output stream—the stream
that print functions use when the stream argument is nil.
The default is t, meaning display in the echo area.
If this is non-nil, that means to print quoted forms using
abbreviated reader syntax, e.g., (quote foo) prints as
'foo, and (function foo) as #'foo. The default
is t.
If this variable is non-nil, then newline characters in strings
are printed as ‘\n’ and formfeeds are printed as ‘\f’.
Normally these characters are printed as actual newlines and formfeeds.
This variable affects the print functions prin1 and print
that print with quoting. It does not affect princ. Here is an
example using prin1:
(prin1 "a\nb")
-| "a
-| b"
⇒ "a
b"
(let ((print-escape-newlines t))
(prin1 "a\nb"))
-| "a\nb"
⇒ "a
b"
In the second expression, the local binding of
print-escape-newlines is in effect during the call to
prin1, but not during the printing of the result.
If this variable is non-nil, control characters in strings are
printed as backslash sequences by the print functions prin1 and
print that print with quoting. If this variable and
print-escape-newlines are both non-nil, the latter takes
precedences for newlines and formfeeds.
If this variable is non-nil, then unibyte non-ASCII
characters in strings are unconditionally printed as backslash sequences
by the print functions prin1 and print that print with
quoting.
Those functions also use backslash sequences for unibyte non-ASCII characters, regardless of the value of this variable, when the output stream is a multibyte buffer or a marker pointing into one.
If this variable is non-nil, then multibyte non-ASCII
characters in strings are unconditionally printed as backslash sequences
by the print functions prin1 and print that print with
quoting.
Those functions also use backslash sequences for multibyte non-ASCII characters, regardless of the value of this variable, when the output stream is a unibyte buffer or a marker pointing into one.
This variable controls printing of ‘charset’ text property on printing
a string. The value should be nil, t, or
default.
If the value is nil, charset text properties are never
printed. If t, they are always printed.
If the value is default, only print charset text
properties if there is an “unexpected” charset property. For
ascii characters, all charsets are considered “expected”.
Otherwise, the expected charset property of a character is
given by char-charset.
The value of this variable is the maximum number of elements to print in any list, vector or bool-vector. If an object being printed has more than this many elements, it is abbreviated with an ellipsis.
If the value is nil (the default), then there is no limit.
(setq print-length 2)
⇒ 2
(print '(1 2 3 4 5))
-| (1 2 ...)
⇒ (1 2 ...)
The value of this variable is the maximum depth of nesting of
parentheses and brackets when printed. Any list or vector at a depth
exceeding this limit is abbreviated with an ellipsis. A value of
nil (which is the default) means no limit.
These are the values for print-length and print-level
used by eval-expression, and thus, indirectly, by many
interactive evaluation commands (see Evaluating
Emacs Lisp Expressions in The GNU Emacs Manual).
These variables are used for detecting and reporting circular and shared structure:
If non-nil, this variable enables detection of circular and
shared structure in printing. See Read Syntax for Circular Objects.
By default, Emacs prints unreadable objects as ‘#<...>"’. For instance:
(prin1-to-string (make-marker))
⇒ "#<marker in no buffer>"
If this variable is non-nil, it should be a function that will
be called to handle printing of these objects. The function will be
called with two arguments: the object and the noescape flag used by
the printing functions (see Output Functions).
The function should return either nil (print the object as
usual), or a string (which will be printed), or any other object
(don’t print the object). For instance:
(let ((print-unreadable-function
(lambda (object escape) "hello")))
(prin1-to-string (make-marker)))
⇒ "hello"
If non-nil, this variable enables detection of uninterned symbols
(see Creating and Interning Symbols) in printing. When this is enabled,
uninterned symbols print with the prefix ‘#:’, which tells the Lisp
reader to produce an uninterned symbol.
If non-nil, that means number continuously across print calls.
This affects the numbers printed for ‘#n=’ labels and
‘#m#’ references.
Don’t set this variable with setq; you should only bind it
temporarily to t with let. When you do that, you should
also bind print-number-table to nil.
This variable holds a vector used internally by printing to implement
the print-circle feature. You should not use it except
to bind it to nil when you bind print-continuous-numbering.
This variable specifies how to print floating-point numbers. The
default is nil, meaning use the shortest output
that represents the number without losing information.
To control output format more precisely, you can put a string in this
variable. The string should hold a ‘%’-specification to be used
in the C function sprintf. For further restrictions on what
you can use, see the variable’s documentation string.
When this variable is non-nil, integers that represent
graphic base characters will be printed using Lisp character syntax
(see Basic Char Syntax). Other numbers are printed the usual way.
For example, the list (4 65 -1 10) would be printed as
‘(4 ?A -1 ?\n)’.
More precisely, values printed in character syntax are those representing characters belonging to the Unicode general categories Letter, Number, Punctuation, Symbol and Private-use (see Character Properties), as well as the control characters having their own escape syntax such as newline.