ccmode: Guessing the Style
6.3.4 Guessing the Style
------------------------
Instead of specifying a style, you can get CC Mode to “guess” your style
by examining an already formatted code buffer. CC Mode then determines
the ”most frequent” offset (
c-offsets-alist) for each of the
syntactic symbols (Indentation Engine Basics) encountered in the
buffer, and the ”most frequent” value of c-basic-offset (
Customizing Indentation), then merges the current style with these
”guesses” to form a new style. This combined style is known as the
“guessed style”.
To do this, call ‘c-guess’ (or one of the other 5 guessing commands)
on your sample buffer. The analysis of your code may take some time.
You can then set the guessed style in any CC Mode buffer with
‘c-guess-install’. You can display the style with ‘c-guess-view’, and
preserve it by copying it into your ‘.emacs’ for future use, preferably
after editing it.
‘M-x c-guess-no-install’
‘M-x c-guess-buffer-no-install’
‘M-x c-guess-region-no-install’
These commands analyze a part of the current buffer and guess the
style from it.
The part of the buffer examined is either the region
(‘c-guess-region-no-install’), the entire buffer
(‘c-guess-buffer-no-install’), or the first ‘c-guess-region-max’
bytes (‘c-guess-no-install’).
Each of these commands can be given an optional prefix argument.
This instructs CC Mode to combine the new guesses with the current
guesses before forming the guessed style.
‘M-x c-guess’
‘M-x c-guess-buffer’
‘M-x c-guess-region’
These commands analyze a part of the current buffer, guess the
style from it, then install the guessed style on the buffer. The
guessed style is given a name based on the buffer’s absolute file
name, and you can then set this style on any CC Mode buffer with
‘C-c .’.
The part of the buffer examined is either the region
(‘c-guess-region’), the entire buffer (‘c-guess-buffer’), or the
first ‘c-guess-region-max’ bytes (‘c-guess’).
Each of these commands can be given an optional prefix argument.
This instructs CC Mode to combine the new guesses with the current
guesses before forming the guessed style.
-- User Option: c-guess-region-max
This variable, default 50000, is the size in bytes of the buffer
portion examined by c-guess and c-guess-no-install. If set to
‘nil’, the entire buffer is examined.
-- User Option: c-guess-offset-threshold
This variable, default 10, is the maximum offset, either outwards
or inwards, which will be taken into account by the analysis
process. Any offset bigger than this will be ignored. For no
limit, set this variable to a large number.
‘M-x c-guess-install’
Set the current buffer’s style to the guessed style. This prompts
you to enter an optional new style name to give to the guessed
style. By default, this name is based on the buffer’s absolute
file name. You can then use this style like any other.
‘M-x c-guess-view’
Display the most recently guessed style in a temporary buffer.
This display is in the form of a ‘c-add-style’ form (Adding
Styles) which can be easily copied to your ‘.emacs’. You will
probably want to edit it first.
The display of the guessed style contains these elements:
Placeholder Name
You should replace this with a style name of your own.
Parent Style
The style current when the guessing began, from which the
guessed style inherits (Config Basics) the settings
which weren’t guessed.
Guessed Offsets
These are the core result of the guessing process. Each of
them is marked by a comment.
Inherited Offsets
These are syntactic offsets which have been taken over from
the parent style. To avoid possible future conflicts, you
should remove either these offsets or the parent style name.
Info Catalog
ccmode: Adding Styles
ccmode: Styles
ccmode: File Styles