Mercurial > molko
view STYLE.md @ 13:c188e9603faf
misc: add basic documentation files
author | David Demelier <markand@malikania.fr> |
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date | Tue, 07 Jan 2020 21:34:03 +0100 |
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children | 98e091b9251e |
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Molko's Adventure CODING STYLE ============================== File content ============ - Use UTF-8 charset, - Use Unix line endings, - Never write two consecutives blank lines. Indent ====== Use tabs to indent and spaces for alignment. Tabs are meant and designed for indenting code and have the advantage of being configurable. On the other hand to keep code clean, you must align content with spaces only *within* a line. Note: we recommend 8 columns to avoid high number of indentations. Example (show whitespace in your editor) ```cpp class foo { public: enum type { dummy_value, // dummy comment other_value // other comment }; void long_function_name(very_long_type x1, very_long_type x2) { const map<string, string> m{ { "hostname", "127.0.0.1" }, { "port", "6667" } }; } }; ``` As a rule of thumb, tabs must always be all length. Example of incorrect usage: ```cpp { "hostname", "127.0.0.1" }, { "port", "6667" } ``` This example will not align correctly if tabstops are not set to 8. C = Style ----- - Do not exceed 80 columns. ### Braces Braces follow the K&R style, they are never placed on their own lines except for function definitions. Do not put braces for single line statements. ```c if (condition) { apply(); add(); } else ok(); if (condition) validate(); if (foo) state = long + conditional + that + requires + several + lines + to + complete; ``` Functions require braces on their own lines. ```c void function() { } ``` Note: the type of a function is broken into its own line. ### Spaces Each reserved keyword (e.g. `if`, `for`, `while`) requires a single space before its argument. Normal function calls do not require it. ```c if (foo) destroy(sizeof (int)); ``` ### Pointers Pointers are always next variable name. ```c void cleanup(struct owner *owner); ``` ### Typedefs Do not use typedef for non-opaque objects. It is allowed for function pointers. ```c struct pack { int x; int y; }; typedef void (*logger)(const char *line); ``` Note: do never add `_t` suffix to typedef's. ### Naming - English names, - No hungarian notation, Almost everything is in `underscore_case` except macros and enumeration constants. ```c #if defined(FOO) # include <foo.hpp> #endif #define MAJOR 1 #define MINOR 0 #define PATCH 0 enum color { COLOR_RED, COLOR_GREEN, COLOR_BLUE }; void add_widget(const struct widget *widget_to_add); ``` ### Header guards Do not use `#pragma once`. Header guards are usually named `PROJECT_COMPONENT_FILENAME_H`. ```c #ifndef FOO_COMMON_UTIL_H #define FOO_COMMON_UTIL_H #endif /* !FOO_COMMON_UTIL_HPP */ ``` ### Enums Enumerations constants are always defined in separate line to allow commenting them as doxygen. Note: enumeration constants are prefixed with its name. ```c enum color { COLOR_RED, COLOR_GREEN, COLOR_BLUE }; ``` ### Switch In a switch case statement, you **must** not declare variables and not indent cases. ```c switch (variable) { case foo: do_some_stuff(); break; default: break; } ``` ### Files - Use `.c` and `.h` as file extensions, - Filenames are all lowercase. ### Comments Avoid useless comments in source files. Comment complex things or why it is done like this. However any public function in the .h **must** be documented as doxygen without exception. ```c /* * Multi line comments look like * this. */ // Short comment ``` Use `#if 0` to comment blocks of code. ```c #if 0 broken_stuff(); #endif ``` ### Includes The includes should always come in the following order. 1. System headers (POSIX mostly) 2. C header 3. Third party libraries 4. Application headers in "" ```c #include <sys/types.h> #include <sys/stat.h> #include <string.h> #include <libircclient.h> #include "foo.h" ``` Programming ----------- ### C Standard Use C99 standard without extensions. ### Assertions Use the `assert` macro from the assert.h header file to verify programming errors. For example, you may use `assert` to verify that the developer access the data between the bounds of an array: ```c int get(struct data *data, unsigned index) { assert(index < data->length); return data->buffer[index]; } ``` The `assert` macro is not meant to check that a function succeeded, this code must not be written that way: ```c assert(listen(10)); ``` ### Return The preferred style is to return early in case of errors. That makes the code more linear and not highly indented. This code is preferred: ```c if (a_condition_is_not_valid) return false; if (an_other_condition) return false; start(); save(); return true; ``` Additional rules: - Do never put parentheses between the returned value, - Do not put a else branch after a return. Shell ===== Write POSIX shell only with no bash, zsh or any extension. Style ----- - Try to keep lines shorter than 80 columns Functions --------- Don't use `function` keyword, just keep the function name. ```sh usage() { } ``` It's usually recommended to prefix functions names with the program name to avoid collisions with global commands. ```sh foo_clean() { } foo_process() { } ``` Options ------- For options, use `getopts` and prefer short options to long unless necessary. Also set OPTERR=0 to avoid printing errors and do it yourself for UX consistency. ```sh OPTERR=0 while getopts "v" arg; do case $arg in v) verbose=1 ;; esac done ``` Naming ------ Use `UPPERCASE` variables for global variables and `lowercase` for temporary or local variables. Markdown ======== Headers ------- For 1st and 2nd level headers, use `===` and `---` delimiters and underline the whole title. Otherwise use `###`. ```markdown Top level title =============== Sub title --------- ### Header 3 #### Header 4 ##### Header 5 ###### Header 6 ``` Lists ----- Use hyphens for unordered lists for consistency, do not indent top level lists, then indent by two spaces each level ```markdown - unordered list 1 - unordered list 2 - sub unordered item 1. unordered list 1 2. unordered list 2 2.1. sub unordered item ``` Code blocks ----------- You can use three backticks and the language specifier or just indent a block by for leading spaces if you don't need syntax. ```cpp std::cout << "hello world" << std::endl; ``` And without syntax: ```markdown This is simple code block. ``` Tables ------ Tables are supported and formatted as following: ```markdown | header 1 | header 2 | |----------|----------| | item 1 | item 2 | ``` Alerts ------ It's possible to prefix a paragraph by one of the following topic, it renders a different block depending on the output format: - Note: - Warning: - Danger: Then, if the paragraph is too long, indent the text correctly. ```markdown Note: this is an information block that is too long to fit between the limits so it is split and indented. ```