calc: Hooks
18.5.7.9 Hooks
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Hooks are variables which contain Lisp functions (or lists of functions)
which are called at various times. Calc defines a number of hooks that
help you to customize it in various ways. Calc uses the Lisp function
‘run-hooks’ to invoke the hooks shown below. Several other
customization-related variables are also described here.
-- Variable: calc-load-hook
This hook is called at the end of ‘calc.el’, after the file has
been loaded, before any functions in it have been called, but after
‘calc-mode-map’ and similar variables have been set up.
-- Variable: calc-ext-load-hook
This hook is called at the end of ‘calc-ext.el’.
-- Variable: calc-start-hook
This hook is called as the last step in a ‘M-x calc’ command. At
this point, the Calc buffer has been created and initialized if
necessary, the Calc window and trail window have been created, and
the “Welcome to Calc” message has been displayed.
-- Variable: calc-mode-hook
This hook is called when the Calc buffer is being created. Usually
this will only happen once per Emacs session. The hook is called
after Emacs has switched to the new buffer, the mode-settings file
has been read if necessary, and all other buffer-local variables
have been set up. After this hook returns, Calc will perform a
‘calc-refresh’ operation, set up the mode line display, then
evaluate any deferred ‘calc-define’ properties that have not been
evaluated yet.
-- Variable: calc-trail-mode-hook
This hook is called when the Calc Trail buffer is being created.
It is called as the very last step of setting up the Trail buffer.
Like ‘calc-mode-hook’, this will normally happen only once per
Emacs session.
-- Variable: calc-end-hook
This hook is called by ‘calc-quit’, generally because the user
presses ‘q’ or ‘C-x * c’ while in Calc. The Calc buffer will be
the current buffer. The hook is called as the very first step,
before the Calc window is destroyed.
-- Variable: calc-window-hook
If this hook is non-‘nil’, it is called to create the Calc window.
Upon return, this new Calc window should be the current window.
(The Calc buffer will already be the current buffer when the hook
is called.) If the hook is not defined, Calc will generally use
‘split-window’, ‘set-window-buffer’, and ‘select-window’ to create
the Calc window.
-- Variable: calc-trail-window-hook
If this hook is non-‘nil’, it is called to create the Calc Trail
window. The variable ‘calc-trail-buffer’ will contain the buffer
which the window should use. Unlike ‘calc-window-hook’, this hook
must _not_ switch into the new window.
-- Variable: calc-embedded-mode-hook
This hook is called the first time that Embedded mode is entered.
-- Variable: calc-embedded-new-buffer-hook
This hook is called each time that Embedded mode is entered in a
new buffer.
-- Variable: calc-embedded-new-formula-hook
This hook is called each time that Embedded mode is enabled for a
new formula.
-- Variable: calc-edit-mode-hook
This hook is called by ‘calc-edit’ (and the other “edit” commands)
when the temporary editing buffer is being created. The buffer
will have been selected and set up to be in ‘calc-edit-mode’, but
will not yet have been filled with text. (In fact it may still
have leftover text from a previous ‘calc-edit’ command.)
-- Variable: calc-mode-save-hook
This hook is called by the ‘calc-save-modes’ command, after Calc’s
own mode features have been inserted into the Calc init file and
just before the “End of mode settings” message is inserted.
-- Variable: calc-reset-hook
This hook is called after ‘C-x * 0’ (‘calc-reset’) has reset all
modes. The Calc buffer will be the current buffer.
-- Variable: calc-other-modes
This variable contains a list of strings. The strings are
concatenated at the end of the modes portion of the Calc mode line
(after standard modes such as “Deg”, “Inv” and “Hyp”). Each string
should be a short, single word followed by a space. The variable
is ‘nil’ by default.
-- Variable: calc-mode-map
This is the keymap that is used by Calc mode. The best time to
adjust it is probably in a ‘calc-mode-hook’. If the Calc
extensions package (‘calc-ext.el’) has not yet been loaded, many of
these keys will be bound to ‘calc-missing-key’, which is a command
that loads the extensions package and “retypes” the key. If your
‘calc-mode-hook’ rebinds one of these keys, it will probably be
overridden when the extensions are loaded.
-- Variable: calc-digit-map
This is the keymap that is used during numeric entry. Numeric
entry uses the minibuffer, but this map binds every non-numeric key
to ‘calcDigit-nondigit’ which generally calls ‘exit-minibuffer’ and
“retypes” the key.
-- Variable: calc-alg-ent-map
This is the keymap that is used during algebraic entry. This is
mostly a copy of ‘minibuffer-local-map’.
-- Variable: calc-store-var-map
This is the keymap that is used during entry of variable names for
commands like ‘calc-store’ and ‘calc-recall’. This is mostly a
copy of ‘minibuffer-local-completion-map’.
-- Variable: calc-edit-mode-map
This is the (sparse) keymap used by ‘calc-edit’ and other temporary
editing commands. It binds <RET>, <LFD>, and ‘C-c C-c’ to
‘calc-edit-finish’.
-- Variable: calc-mode-var-list
This is a list of variables which are saved by ‘calc-save-modes’.
Each entry is a list of two items, the variable (as a Lisp symbol)
and its default value. When modes are being saved, each variable
is compared with its default value (using ‘equal’) and any
non-default variables are written out.
-- Variable: calc-local-var-list
This is a list of variables which should be buffer-local to the
Calc buffer. Each entry is a variable name (as a Lisp symbol).
These variables also have their default values manipulated by the
‘calc’ and ‘calc-quit’ commands; 
Multiple Calculators.
Since ‘calc-mode-hook’ is called after this list has been used the
first time, your hook should add a variable to the list and also
call ‘make-local-variable’ itself.
Info Catalog
calc: Formatting Lisp Functions
calc: Internals