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diff --git a/doc/coding_standards.md b/doc/coding_standards.md new file mode 100644 index 0000000..b071876 --- /dev/null +++ b/doc/coding_standards.md @@ -0,0 +1,147 @@ +Coding Standards +================ + +shFlags is more than just a simple 20 line shell script. It is a pretty +significant library of shell code that at first glance is not that easy to +understand. To improve code readability and usability, some guidelines have been +set down to make the code more understandable for anyone who wants to read or +modify it. + +Function declaration +-------------------- + +Declare functions using the following form: + +```sh +doSomething() { + echo 'done!' +} +``` + +One-line functions are allowed if they can fit within the 80 char line limit. + +```sh +doSomething() { echo 'done!'; } +``` + +Function documentation +---------------------- + +Each function should be preceded by a header that provides the following: + +1. A one-sentence summary of what the function does. + +1. (optional) A longer description of what the function does, and perhaps some + special information that helps convey its usage better. + +1. Args: a one-line summary of each argument of the form: + + `name: type: description` + +1. Output: a one-line summary of the output provided. Only output to STDOUT + must be documented, unless the output to STDERR is of significance (i.e. not + just an error message). The output should be of the form: + + `type: description` + +1. Returns: a one-line summary of the value returned. Returns in shell are + always integers, but if the output is a true/false for success (i.e. a + boolean), it should be noted. The output should be of the form: + + `type: description` + +Here is a sample header: + +``` +# Return valid getopt options using currently defined list of long options. +# +# This function builds a proper getopt option string for short (and long) +# options, using the current list of long options for reference. +# +# Args: +# _flags_optStr: integer: option string type (__FLAGS_OPTSTR_*) +# Output: +# string: generated option string for getopt +# Returns: +# boolean: success of operation (always returns True) +``` + +Variable and function names +--------------------------- + +All shFlags specific constants, variables, and functions will be prefixed +appropriately with 'flags'. This is to distinguish usage in the shFlags code +from users own scripts so that the shell name space remains predictable to +users. The exceptions here are the standard `assertEquals`, etc. functions. + +All non built-in constants and variables will be surrounded with squiggle +brackets, e.g. `${flags_someVariable}` to improve code readability. + +Due to some shells not supporting local variables in functions, care in the +naming and use of variables, both public and private, is very important. +Accidental overriding of the variables can occur easily if care is not taken as +all variables are technically global variables in some shells. + +Type | Sample +---- | ------ +global public constant | `FLAGS_TRUE` +global private constant | `__FLAGS_SHELL_FLAGS` +global public variable | `flags_variable` +global private variable | `__flags_variable` +global macro | `_FLAGS_SOME_MACRO_` +public function | `flags_function` +public function, local variable | ``flags_variable_` +private function | `_flags_function` +private function, local variable | `_flags_variable_` + +Where it makes sense to improve readability, variables can have the first +letter of the second and later words capitalized. For example, the local +variable name for the help string length is `flags_helpStrLen_`. + +There are three special-case global public variables used. They are used due to +overcome the limitations of shell scoping or to prevent forking. The three +variables are: + +- `flags_error` +- `flags_output` +- `flags_return` + +Local variable cleanup +---------------------- + +As many shells do not support local variables, no support for cleanup of +variables is present either. As such, all variables local to a function must be +cleared up with the `unset` built-in command at the end of each function. + +Indentation +----------- + +Code block indentation is two (2) spaces, and tabs may not be used. + +```sh +if [ -z 'some string' ]; then + someFunction +fi +``` + +Lines of code should be no longer than 80 characters unless absolutely +necessary. When lines are wrapped using the backslash character '\', subsequent +lines should be indented with four (4) spaces so as to differentiate from the +standard spacing of two characters, and tabs may not be used. + +```sh +for x in some set of very long set of arguments that make for a very long \ + that extends much too long for one line +do + echo ${x} +done +``` + +When a conditional expression is written using the built-in [ command, and that +line must be wrapped, place the control || or && operators on the same line as +the expression where possible, with the list to be executed on its own line. + +```sh +[ -n 'some really long expression' -a -n 'some other long expr' ] && \ + echo 'that was actually true!' +``` |