emacs: Lisp Interaction
27.10 Lisp Interaction Buffers
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When Emacs starts up, it contains a buffer named ‘*scratch*’, which is
provided for evaluating Emacs Lisp expressions interactively. Its major
mode is Lisp Interaction mode. You can also enable Lisp Interaction
mode by typing ‘M-x lisp-interaction-mode’.
In the ‘*scratch*’ buffer, and other Lisp Interaction mode buffers,
‘C-j’ (‘eval-print-last-sexp’) evaluates the Lisp expression before
point, and inserts the value at point. Thus, as you type expressions
into the buffer followed by ‘C-j’ after each expression, the buffer
records a transcript of the evaluated expressions and their values. All
other commands in Lisp Interaction mode are the same as in Emacs Lisp
mode.
At startup, the ‘*scratch*’ buffer contains a short message, in the
form of a Lisp comment, that explains what it is for. This message is
controlled by the variable ‘initial-scratch-message’, which should be
either a documentation string, or ‘nil’ (which means to suppress the
message).
An alternative way of evaluating Emacs Lisp expressions interactively
is to use Inferior Emacs Lisp mode, which provides an interface rather
like Shell mode (
Shell Mode) for evaluating Emacs Lisp
expressions. Type ‘M-x ielm’ to create an ‘*ielm*’ buffer which uses
this mode. For more information, see that command’s documentation.
Info Catalog
emacs: Lisp Eval
emacs: Building
emacs: External Lisp