Elisp: Print, Output

Print to Messages Buffer

message

(message FORMAT_STRING &rest ARGS)

Print a Format String to the Messages Buffer .

(message "Name is: %s" "Joe")

Insert Text to Current Buffer

insert

(insert &rest ARGS)

Insert string to current buffer, at cursor position.

(insert "something")

〔see Elisp: Text Editing Functions〕

Print to a Buffer

print

(print OBJECT &optional TARGET)

• Print lisp object in lisp syntax.
• Print a newline at end.
• Optional arg for a target buffer, or other functions.

Add format if you need to print multiple items in one shot. 〔see Elisp: Format String〕

When writing a elisp script that does batch processing, it's best to print to your own buffer, because the Messages Buffer scrolls off.

(setq xbuff (generate-new-buffer "*my output*"))

(print "something" xbuff)

(switch-to-buffer xbuff )

〔see Buffer Functions〕

prin1

(prin1 OBJECT &optional TARGET)

Like print, but does not add newline at end.

princ

(princ OBJECT &optional TARGET)

• Print in more human-readable format. (e.g. no string delimiters.)
• No newline at end.

warn

(warn FORMAT_STRING &rest ARGS)

Print a warning of Format String to a buffer named *Warnings* .

(warn "Name is: %s" "Joe")

Temporarily Specify a Buffer for Output

with-output-to-temp-buffer

(with-output-to-temp-buffer BUFNAME &rest BODY)

Bind standard-output to buffer BUFNAME, eval BODY, then show that buffer.

• buffer is cleared before printing to it.
• print functions default to print to the buffer.

(let ((xbuff (generate-new-buffer "*my output*")))
  (with-output-to-temp-buffer xbuff
    ;; this is printed to xbuff
    (print "abc")
    ;;
    ))

Reference

• Output Functions (ELISP Manual)