This has multiple effects:
1) The i3 codebase is now consistently formatted. clang-format uncovered
plenty of places where inconsistent code made it into our code base.
2) When writing code, you don’t need to think or worry about our coding
style. Write it in yours, then run clang-format-3.5
3) When submitting patches, we don’t need to argue about coding style.
The basic idea is that we don’t want to care about _how_ we write the
code, but _what_ it does :). The coding style that we use is defined in
the .clang-format config file and is based on the google style, but
adapted in such a way that the number of modifications to the i3 code
base is minimal.
parse_command returns a struct that contains useful information about
the result of a command as a whole (instead of the intermediate
representation used during parsing).
parse_command now requires the caller to allocate the yajl_gen used for
generating a json reply. This is passed as the second parameter to
parse_command. If NULL is passed, no json reply will be generated.
Change the name of structs CommandResult and ConfigResult to
CommandResultIR and ConfigResultIR to show they are an intermediate
representation used during parsing.
e.g. pressing Mod1+x when having the following in your configfile:
bindsym Mod1+x some invalid command
will lead to an i3-nagbar instance popping up, offering you to view the
error log (which will contain parser errors from this commit on).
See also:
http://article.gmane.org/gmane.linux.kernel/1268792
The C compiler will handle (void) as "no arguments" and () as "variadic
function" (equivalent to (...)) which might lead to subtle errors, such
as the one which was fixed with commit 0ea64ae4.
This change has two implications:
1) tree_render() will now be called precisely once for input which consists of
multiple commands (like "focus left; focus right"). Also, the caller of
parse_command() has to call it. This makes us able to fix tickets such as
ticket #608 (where multiple tree_render() calls are noticable).
2) The output of a command is now a JSON array of return values of the
individual subcommands. In the case of "focus left; focus right", this is:
[{"success":true}, {"success":true}]
While this is incompatible with what i3 returned before, the return value of
commands was undocumented and therefore not subject to our API stability.
On the rationale of using a custom parser instead of a lex/yacc one, see this
quote from src/commands_parser.c:
We use a hand-written parser instead of lex/yacc because our commands are
easy for humans, not for computers. Thus, it’s quite hard to specify a
context-free grammar for the commands. A PEG grammar would be easier, but
there’s downsides to every PEG parser generator I have come accross so far.
This parser is basically a state machine which looks for literals or strings
and can push either on a stack. After identifying a literal or string, it
will either transition to the current state, to a different state, or call a
function (like cmd_move()).
Special care has been taken that error messages are useful and the code is
well testable (when compiled with -DTEST_PARSER it will output to stdout
instead of actually calling any function).
During the migration phase (I plan to completely switch to this parser before
4.2 will be released), the new parser will parse every command you send to
i3 and save the resulting call stack. Then, the old parser will parse your
input and actually execute the commands. Afterwards, both call stacks will be
compared and any differences will be logged.
The new parser works with 100% of the test suite and produces identical call
stacks.
shdown