diff options
Diffstat (limited to 'Documentation/technical/api-parse-options.txt')
| -rw-r--r-- | Documentation/technical/api-parse-options.txt | 129 |
1 files changed, 94 insertions, 35 deletions
diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt index 50f9e9ac17..27bd701c0d 100644 --- a/Documentation/technical/api-parse-options.txt +++ b/Documentation/technical/api-parse-options.txt @@ -1,7 +1,7 @@ parse-options API ================= -The parse-options API is used to parse and massage options in git +The parse-options API is used to parse and massage options in Git and to provide a usage help with consistent look. Basics @@ -21,7 +21,7 @@ that allow to change the behavior of a command. * There are basically two forms of options: 'Short options' consist of one dash (`-`) and one alphanumeric character. - 'Long options' begin with two dashes (`\--`) and some + 'Long options' begin with two dashes (`--`) and some alphanumeric characters. * Options are case-sensitive. @@ -29,9 +29,9 @@ that allow to change the behavior of a command. The parse-options API allows: -* 'sticked' and 'separate form' of options with arguments. - `-oArg` is sticked, `-o Arg` is separate form. - `\--option=Arg` is sticked, `\--option Arg` is separate form. +* 'stuck' and 'separate form' of options with arguments. + `-oArg` is stuck, `-o Arg` is separate form. + `--option=Arg` is stuck, `--option Arg` is separate form. * Long options may be 'abbreviated', as long as the abbreviation is unambiguous. @@ -39,11 +39,14 @@ The parse-options API allows: * Short options may be bundled, e.g. `-a -b` can be specified as `-ab`. * Boolean long options can be 'negated' (or 'unset') by prepending - `no-`, e.g. `\--no-abbrev` instead of `\--abbrev`. + `no-`, e.g. `--no-abbrev` instead of `--abbrev`. Conversely, + options that begin with `no-` can be 'negated' by removing it. + Other long options can be unset (e.g., set string to NULL, set + integer to 0) by prepending `no-`. -* Options and non-option arguments can clearly be separated using the `\--` - option, e.g. `-a -b \--option \-- \--this-is-a-file` indicates that - `\--this-is-a-file` must not be processed as an option. +* Options and non-option arguments can clearly be separated using the `--` + option, e.g. `-a -b --option -- --this-is-a-file` indicates that + `--this-is-a-file` must not be processed as an option. Steps to parse options ---------------------- @@ -75,7 +78,7 @@ before the full parser, which in turn shows the full help message. Flags are the bitwise-or of: `PARSE_OPT_KEEP_DASHDASH`:: - Keep the `\--` that usually separates options from + Keep the `--` that usually separates options from non-option arguments. `PARSE_OPT_STOP_AT_NON_OPTION`:: @@ -113,25 +116,40 @@ say `static struct option builtin_add_options[]`. There are some macros to easily define options: `OPT__ABBREV(&int_var)`:: - Add `\--abbrev[=<n>]`. + Add `--abbrev[=<n>]`. -`OPT__DRY_RUN(&int_var)`:: - Add `-n, \--dry-run`. +`OPT__COLOR(&int_var, description)`:: + Add `--color[=<when>]` and `--no-color`. -`OPT__QUIET(&int_var)`:: - Add `-q, \--quiet`. +`OPT__DRY_RUN(&int_var, description)`:: + Add `-n, --dry-run`. -`OPT__VERBOSE(&int_var)`:: - Add `-v, \--verbose`. +`OPT__FORCE(&int_var, description)`:: + Add `-f, --force`. + +`OPT__QUIET(&int_var, description)`:: + Add `-q, --quiet`. + +`OPT__VERBOSE(&int_var, description)`:: + Add `-v, --verbose`. `OPT_GROUP(description)`:: Start an option group. `description` is a short string that describes the group or an empty string. Start the description with an upper-case letter. -`OPT_BOOLEAN(short, long, &int_var, description)`:: - Introduce a boolean option. - `int_var` is incremented on each use. +`OPT_BOOL(short, long, &int_var, description)`:: + Introduce a boolean option. `int_var` is set to one with + `--option` and set to zero with `--no-option`. + +`OPT_COUNTUP(short, long, &int_var, description)`:: + Introduce a count-up option. + Each use of `--option` increments `int_var`, starting from zero + (even if initially negative), and `--no-option` resets it to + zero. To determine if `--option` or `--no-option` was encountered at + all, initialize `int_var` to a negative value, and if it is still + negative after parse_options(), then neither `--option` nor + `--no-option` was seen. `OPT_BIT(short, long, &int_var, description, mask)`:: Introduce a boolean option. @@ -142,12 +160,9 @@ There are some macros to easily define options: If used, `int_var` is bitwise-anded with the inverted `mask`. `OPT_SET_INT(short, long, &int_var, description, integer)`:: - Introduce a boolean option. - If used, set `int_var` to `integer`. - -`OPT_SET_PTR(short, long, &ptr_var, description, ptr)`:: - Introduce a boolean option. - If used, set `ptr_var` to `ptr`. + Introduce an integer option. + `int_var` is set to `integer` with `--option`, and + reset to zero with `--no-option`. `OPT_STRING(short, long, &str_var, arg_str, description)`:: Introduce an option with string argument. @@ -157,10 +172,20 @@ There are some macros to easily define options: Introduce an option with integer argument. The integer is put into `int_var`. +`OPT_MAGNITUDE(short, long, &unsigned_long_var, description)`:: + Introduce an option with a size argument. The argument must be a + non-negative integer and may include a suffix of 'k', 'm' or 'g' to + scale the provided value by 1024, 1024^2 or 1024^3 respectively. + The scaled value is put into `unsigned_long_var`. + `OPT_DATE(short, long, &int_var, description)`:: Introduce an option with date argument, see `approxidate()`. The timestamp is put into `int_var`. +`OPT_EXPIRY_DATE(short, long, &int_var, description)`:: + Introduce an option with expiry date argument, see `parse_expiry_date()`. + The timestamp is put into `int_var`. + `OPT_CALLBACK(short, long, &var, arg_str, description, func_ptr)`:: Introduce an option with argument. The argument will be fed into the function given by `func_ptr` @@ -183,16 +208,50 @@ There are some macros to easily define options: arguments. Short options that happen to be digits take precedence over it. +`OPT_COLOR_FLAG(short, long, &int_var, description)`:: + Introduce an option that takes an optional argument that can + have one of three values: "always", "never", or "auto". If the + argument is not given, it defaults to "always". The `--no-` form + works like `--long=never`; it cannot take an argument. If + "always", set `int_var` to 1; if "never", set `int_var` to 0; if + "auto", set `int_var` to 1 if stdout is a tty or a pager, + 0 otherwise. + +`OPT_NOOP_NOARG(short, long)`:: + Introduce an option that has no effect and takes no arguments. + Use it to hide deprecated options that are still to be recognized + and ignored silently. + +`OPT_PASSTHRU(short, long, &char_var, arg_str, description, flags)`:: + Introduce an option that will be reconstructed into a char* string, + which must be initialized to NULL. This is useful when you need to + pass the command-line option to another command. Any previous value + will be overwritten, so this should only be used for options where + the last one specified on the command line wins. + +`OPT_PASSTHRU_ARGV(short, long, &argv_array_var, arg_str, description, flags)`:: + Introduce an option where all instances of it on the command-line will + be reconstructed into an argv_array. This is useful when you need to + pass the command-line option, which can be specified multiple times, + to another command. + +`OPT_CMDMODE(short, long, &int_var, description, enum_val)`:: + Define an "operation mode" option, only one of which in the same + group of "operating mode" options that share the same `int_var` + can be given by the user. `enum_val` is set to `int_var` when the + option is used, but an error is reported if other "operating mode" + option has already set its value to the same `int_var`. + The last element of the array must be `OPT_END()`. If not stated otherwise, interpret the arguments as follows: * `short` is a character for the short option - (e.g. `\'e\'` for `-e`, use `0` to omit), + (e.g. `'e'` for `-e`, use `0` to omit), * `long` is a string for the long option - (e.g. `"example"` for `\--example`, use `NULL` to omit), + (e.g. `"example"` for `--example`, use `NULL` to omit), * `int_var` is an integer variable, @@ -217,7 +276,7 @@ The callback mechanism is as follows: * Inside `func`, the only interesting member of the structure given by `opt` is the void pointer `opt->value`. - `\*opt->value` will be the value that is saved into `var`, if you + `*opt->value` will be the value that is saved into `var`, if you use `OPT_CALLBACK()`. For example, do `*(unsigned long *)opt->value = 42;` to get 42 into an `unsigned long` variable. @@ -242,10 +301,10 @@ Examples -------- See `test-parse-options.c` and -`builtin-add.c`, -`builtin-clone.c`, -`builtin-commit.c`, -`builtin-fetch.c`, -`builtin-fsck.c`, -`builtin-rm.c` +`builtin/add.c`, +`builtin/clone.c`, +`builtin/commit.c`, +`builtin/fetch.c`, +`builtin/fsck.c`, +`builtin/rm.c` for real-world examples. |