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diff --git a/notes/coding_standard.rst b/notes/coding_standard.rst deleted file mode 100644 index f761db7..0000000 --- a/notes/coding_standard.rst +++ /dev/null @@ -1,427 +0,0 @@ -libmaple Coding Standards -========================= - -Author: Marti Bolivar (mbolivar@leaflabs.com) - -LeafLabs team members are required to follow these when producing new -code. Community contributors to libmaple are strongly encouraged to -do so; following these rules will greatly increase the probability -that your patches will be folded in. - -In general, do it like this unless there's a really good reason why -not. You being lazy doesn't count as a good reason. Most, if not -all, of these decisions are entirely arbitrary, but it's important for -readability that we be consistent. - -The file ``.dir-locals.el`` in the libmaple root directory already -ensures that many of these standards are followed by default in Emacs -(but not on Windows, where it would need to be named -``_dir_locals.el``, and no way, man). There's also some elisp -scattered about this file which will provide you additional help. - -Vim customizations to do the same thing would be nice (hint, hint)! - -.. contents:: Contents - :local: - -License -------- - -.. highlight:: scheme - -- Put an MIT license at the beginning of the file (look at any of our - source files for an example). Copyright should go either to you or - to LeafLabs, LLC. - - Emacs: if you don't like seeing the license, you should use - elide-head (which will hide it for you). You can use the following:: - - (require 'elide-head) - (setq programming-mode-hooks '(c-mode-hook c++-mode-hook)) - (add-to-list 'elide-head-headers-to-hide - '("The MIT License" . "DEALINGS IN\n [*] THE SOFTWARE")) - (add-to-list 'elide-head-headers-to-hide - '("The MIT License" . "DEALINGS IN THE\n...SOFTWARE")) - (dolist (hook programming-mode-hooks) - (add-hook hook (lambda () (elide-head)))) - -Whitespace/Indentation ----------------------- - -- 4 space indents. [Set in ``.dir-locals.el``] - -- Unix newlines. [Some exceptions are currently grandfathered in; - these will go away in time.] - -- No tab characters. [Set in ``.dir-locals.el``] - -- No trailing whitespace. For help getting this (and no tab - characters) done automatically in Emacs, you can use this: - - http://github.com/mbolivar/code-fascism - - I hear tell you can get something similar in Vim; ask around, I - guess. - -- Files end in exactly one newline. [The presence of a newline at EOF - is already done by ``c-require-final-newline`` in recent versions of - Emacs.] - -- Exactly two newlines separate source paragraphs (you do separate - your code into paragraphs, don't you?). - -- The first line in a function is non-blank. - -.. highlight:: cpp - -- Exactly one space after ``if``, ``else``, ``for``, and ``while``, - before the following ``{`` or ``(``. One space before ``else``, - after the preceding ``}``. For example:: - - // This is good; we like this: - if (foo) { - while (quux) { - bar(); - } - } else { - baz(); - } - - // THIS IS BAD! DON'T DO THIS: - if(foo){ - while(quux){ - bar(); - } - }else{ - baz(); - } - -- Exactly one space in between binary arithmetic, logical, and - comparison operators and their operands. This doesn't apply to the - . and -> operators. Examples:: - - // This is good: - int x = a + b * (c - d); - if (x != 0 && a > 7) { - SerialUSB.println(x); - } - - // THIS IS BAD! - int x = a+b*(c-d); - if (x!=0 && a>7) { - SerialUSB.println(x); - } - - // This is good: - uint32 adc_data = ADC1_BASE->DR; - SerialUSB.println(adc_data); - - // THIS IS BAD! - uint32 adc_data = ADC1_BASE -> DR; - SerialUSB . println(adc_data); - -- No space between a unary operator and its operand. Examples:: - - // Good: - x++; - - // BAD! - x ++; - - // Good: - y = -x; - - // BAD! - y = - x; - -- If you need to break up a long line: - - * Prefer to break up long expressions after a binary operator. Example:: - - // Good: - if (some_really_long_conditional_wow_this_really_goes_on_forever || - maybe_something_else_could_happen_too) { - ... - } - - // BAD! - if (some_really_long_conditional_wow_this_really_goes_on_forever - || maybe_something_else_could_happen_too) { - ... - } - - * When breaking up a function's arguments over multiple lines, align - the arguments on subsequent lines with the first argument. - Example:: - - // Good: - return_type value_i_got = function_with_a_really_long_name(argument1, - argument2, - argument3); - - // BAD! - return_type value_i_got = function_with_a_really_long_name(argument1, - argument2, - argument3); - - // BAD! - return_type value_i_got = function_with_a_really_long_name(argument1, - argument2, - argument3); - -- In function invocations, no space in between the function name and - the opening parenthesis. Example:: - - // Good: - SerialUSB.println("Hello, world!"); - - // BAD! - SerialUSB.println ("Hello, world!"); - -- Don't indent C code within a conditionally-compiled ``extern "C"`` - block. Example:: - - // Good: - #ifdef __cplusplus - extern "C"{ - #endif - - void some_c_function(void); - - #ifdef __cplusplus - } // extern "C" - #endif - - // BAD! - #ifdef __cplusplus - extern "C"{ - #endif - - void some_c_function(void); - - #ifdef __cplusplus - } // extern "C" - #endif - -.. highlight:: scheme - - Emacs does the "bad" behavior by default, which can be very - annoying. You can turn this off with:: - - (defun c-mode-inextern-lang-hook () - (setcdr (assq 'inextern-lang c-offsets-alist) '-)) - (add-hook 'c-mode-hook c-mode-inextern-lang-hook) - -Comments --------- - -.. highlight:: c++ - -- Multi-line comments are pretty flexible. Any of these is fine:: - - /* Comment starts here. - * Continued lines have a '*' before them. - * The comment can end after the last line. - */ - - /* Comment starts here. - * The comment can end on the same line. */ - - /* - * You can also place a newline after the opening "/*". - */ - -- Doxygen comments are multi-line comments that begin with ``/**`` - instead. - -- Single-line comments on the same line are ``//`` in C++. (That's OK - in C as well). - -- Single-line comments on their own source line should be ``/* */`` in - C, but can also be ``//`` in C++. (This isn't of great importance). - In Emacs, you can use M-; (comment-dwim), and it'll Do What You - Mean. - -Braces ------- - -- Mostly 1TBS: - - http://en.wikipedia.org/wiki/Indent_style#Variant:_1TBS - - The only difference is that the opening brace of a function's - definition occurs exactly one space character after the closing - parenthesis in that function's parameter list. Example:: - - void func(void) { - ... - } - -Naming conventions ------------------- - -There's always a fight about upper and lower case vs. underscores. -We'll handle this as follows. - -- First, ``Dont_Mix_Like_This``, because ``It_Looks_Really_Ugly``, ok? - [There's been some debate about this, and some exceptions are - already grandfathered in, so in order to settle it, let's call this - a "recommendation" instead of "requirement".] - -- Variables: Use underscores to separate words in C identifiers:: - - int some_example_name; - - User-facing C++ variables should be camel cased - (``thisIsAnExample``, ``boardPWMPins``, etc.), for consistency with - the Arduino style. It's probably a good idea for you to case - non-user facing C++ variables in the C style; this will help - disambiguate what's part of the Wirish API and what's not. - -- Classes: Pascal case. So ``ThisIsAClassName``, but ``thisIsNot``, - ``this_is_not``, and like I said, - ``Dont_You_DareTryANYTHING_STUPID``. - -- Functions: C functions are all lowercase, and words are separated by - underscores. C++ method names are camel cased. - -- Structs: Usually like variables (``adc_dev``, ``adc_reg_map``, - etc.), but it's not crucial. Don't feel obliged to put ``_t`` at - the end of the type name; we don't. - -- Macros and constants: all caps, separated by underscores. C++ - variables with the ``const`` qualifier generally aren't considered - "constants" for the purposes of this rule; i.e., they are cased - according to the rules for variables. We make an exception for - ``PIN_MAP``, because it's the central Wirish data structure. - -- foo.h gets ``#ifdef``\ 'ed to ``_FOO_H_``. - -- Acronyms: The case of letters in an acronym is determined by the - case of the first letter in the acronym, which is determined by - following the above rules. Examples:: - - // Good: - void usb_func() { ... } - void frob_usb_disc() { ... } - class SomethingUSB { - void usbInit(); - void initUSB(); - }; - - // BAD: - class BadUsb { ... }; // say "GoodUSB" instead - void swizzle_USB_disc() { ... } // say "swizzle_usb_disc" instead - -Documentation -------------- - -- You **must** document your code. At a bare minimum, this means - Doxygen comments on every user-facing function and type. - Additionally, you need to individually document the fields and - enumerator values of ``struct``\ s and ``enum``\ s. See any - register map type's definition for an example. - -- For libmaple proper, you don't need comments for each register bit - definition (for now). - -- Doxygen comments generally just belong on types, functions, - etc. that are part of the public user-facing API. This generally - means that if there's ReST documentation for it under docs/source/, - it needs Doxygen comments, and that ReST should use Breathe to pull - that Doxygen comment out. (For more info on this, see docs/README). - - There are some exceptions to this rule since Breathe isn't totally - mature yet and Sphinx's C++ domain is still in flux. In these - cases, document the code "manually" in ReST. - - This should be avoided if at all possible, since it creates a - maintenance burden of documenting things in two places at once, and - makes it easier for documentation to go stale. - - If you do have to document something manually, put a comment in the - source file informing future maintainers about it, so they'll pay - extra attention when making changes. - -- When adding peripheral support, it would be nice if you put - longer-form comments into the /notes/ directory, with a comment in - the corresponding .h file referring to it. See /libmaple/dac.h for - an example. - - This lets us keep the source files relatively free of "introductory" - material, while allowing new readers a convenient starting point. - These longer-form notes also have a habit of turning into - user-facing documentation. - -- For libmaple proper (the pure C library under libmaple/); the - convention is to document any user-facing function at the point where - it is defined. In particular, this means you should document an - externally-linked function defined in a .c file in that .c file, not - in the header file where it is declared to the user. - -General Formatting ------------------- - -.. highlight:: scheme - -- Keep it 80-column clean. That means Emacs says the largest column - number=79. You should turn on column number mode to help you out: - - (column-number-mode 1) - - You can get more help from lineker-mode: - - http://www.helsinki.fi/~sjpaavol/programs/lineker.el - - Just put lineker.el somewhere in your load-path, and: - - (require 'lineker) - (dolist (hook '(c-mode-hook c++-mode-hook)) - (add-hook hook (lambda () (lineker-mode 1)))) - -.. highlight:: cpp - -Language Features and Compiler Extensions ------------------------------------------ - -- In libmaple proper, aim for C99 compatibility. Some GCC extensions - are OK, but let's not go crazy. - -- If you'd like to get code into libmaple which uses a GCC extension - not already in use elsewhere, ask a LeafLabs developer (or another - one, if you are one) what they think about it first. - -- Explicitly approved GCC extensions: - - * ``asm volatile``: - http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html - - * ``Nested functions``: - http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html - -- In wirish, generally be very conservative when using C++ features - that aren't part of C. We are forced to use C++ for Arduino - compatibility (and the general Arduino style of pretending that an - object is a library), but it's an angry beast, and we don't want to - provoke it. The mantra is "C with classes". - -- Explicitly approved C++ features: - - * Initializers that aren't constant; e.g. the ``gpio_dev*`` values - in a ``PIN_MAP``. - - * Default arguments: e.g., the timeout argument defaulting to 0 - (meaning to wait forever) in ``waitForButtonPress()``. - -- Explicitly forbidden C++ features: - - * Templates - -- C++ features that are conditionally allowed, but require explicit - approval from at least two libmaple developers (one of which may be - yourself): - - * Operator overloading: Never allowed when it's just for style. - Potentially allowed when you're implementing a class that models a - mathematical structure, and you'd like to implement - e.g. ``operator+()``. |