diff --git a/CODECONVENTIONS.md b/CODECONVENTIONS.md index d6af0418e4..d3f71cb083 100644 --- a/CODECONVENTIONS.md +++ b/CODECONVENTIONS.md @@ -206,14 +206,21 @@ adhere to the existing style and use `tools/codeformat.py` to check any changes. The main conventions, and things not enforceable via the auto-formatter, are described below. -White space: +As the MicroPython code base is over ten years old, not every source file +conforms fully to these conventions. If making small changes to existing code, +then it's usually acceptable to follow the existing code's style. New code or +major changes should follow the conventions described here. + +## White space + - Expand tabs to 4 spaces. - Don't leave trailing whitespace at the end of a line. - For control blocks (if, for, while), put 1 space between the keyword and the opening parenthesis. - Put 1 space after a comma, and 1 space around operators. -Braces: +## Braces + - Use braces for all blocks, even no-line and single-line pieces of code. - Put opening braces on the end of the line it belongs to, not on @@ -221,18 +228,43 @@ Braces: - For else-statements, put the else on the same line as the previous closing brace. -Header files: +## Header files + - Header files should be protected from multiple inclusion with #if directives. See an existing header for naming convention. -Names: +## Names + - Use underscore_case, not camelCase for all names. - Use CAPS_WITH_UNDERSCORE for enums and macros. - When defining a type use underscore_case and put '_t' after it. -Integer types: MicroPython runs on 16, 32, and 64 bit machines, so it's -important to use the correctly-sized (and signed) integer types. The -general guidelines are: +### Public names (declared in headers) + +- MicroPython-specific names (especially any declared in `py/` and `extmod/` + directories) should generally start with `mp_` or `MP_`. +- Functions and variables declared in a header should generally share a longer + common prefix. Usually the prefix matches the file name (i.e. items defined in + `py/obj.c` are declared in `py/obj.h` and should be prefixed `mp_obj_`). There + are exceptions, for example where one header file contains declarations + implemented in multiple source files for expediency. + +### Private names (specific to a single .c file) + +- For static functions and variables exposed to Python (i.e. a static C function + that is wrapped in `MP_DEFINE_CONST_FUN_...` and attached to a module), use + the file-level shared common prefix, i.e. name them as if the function or + variable was not static. +- Other static definitions in source files (i.e. functions or variables defined + in a .c file that are only used within that .c file) don't need any prefix + (specifically: no `s_` or `_` prefix, and generally avoid adding the + file-level common prefix). + +## Integer types + +MicroPython runs on 16, 32, and 64 bit machines, so it's important to use the +correctly-sized (and signed) integer types. The general guidelines are: + - For most cases use mp_int_t for signed and mp_uint_t for unsigned integer values. These are guaranteed to be machine-word sized and therefore big enough to hold the value from a MicroPython small-int @@ -241,11 +273,13 @@ general guidelines are: - You can use int/uint, but remember that they may be 16-bits wide. - If in doubt, use mp_int_t/mp_uint_t. -Comments: +## Comments + - Be concise and only write comments for things that are not obvious. - Use `// ` prefix, NOT `/* ... */`. No extra fluff. -Memory allocation: +## Memory allocation + - Use m_new, m_renew, m_del (and friends) to allocate and free heap memory. These macros are defined in py/misc.h.