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| -rw-r--r-- | README.rst | 98 |
1 files changed, 52 insertions, 46 deletions
@@ -1,4 +1,4 @@ -.. vi: tw=100 +.. vi: tw=100 noet Getgopt ======= @@ -19,40 +19,40 @@ There is only 1 function for you to use, and that is ``getgopt.Getopt()``. The f .. code-block:: go - package main - - import ( - "fmt" - "os" - - "github.com/Mango0x45/getgopt" - ) - - func main() { - for opt := byte(0); getgopt.Getopt(len(os.Args), os.Args, ":a:bcd", &opt); { - switch opt { - case 'a': - fmt.Printf("Parsed the -a flag with the argument '%s'\n", - getgopt.Optarg) - case 'b': - fmt.Println("Parsed the -b flag") - case 'c': - /* ... */ - case 'd': - /* ... */ - case '?': - fmt.Fprintf(os.Stderr, "Invalid flag '%c', read the manpage\n", - getgopt.Optopt) - os.Exit(1) - case ':': - fmt.Fprintf(os.Stderr, "The flag '%c' requires an argument\n", - getgopt.Optopt) - os.Exit(1) - } - } - - fmt.Printf("The first non-option argument is '%s'\n", os.Args[getgopt.Optind]) - } + package main + + import ( + "fmt" + "os" + + "github.com/Mango0x45/getgopt" + ) + + func main() { + for opt := byte(0); getgopt.Getopt(len(os.Args), os.Args, ":a:bcd", &opt); { + switch opt { + case 'a': + fmt.Printf("Parsed the -a flag with the argument '%s'\n", + getgopt.Optarg) + case 'b': + fmt.Println("Parsed the -b flag") + case 'c': + /* ... */ + case 'd': + /* ... */ + case '?': + fmt.Fprintf(os.Stderr, "Invalid flag '%c', read the manpage\n", + getgopt.Optopt) + os.Exit(1) + case ':': + fmt.Fprintf(os.Stderr, "The flag '%c' requires an argument\n", + getgopt.Optopt) + os.Exit(1) + } + } + + fmt.Printf("The first non-option argument is '%s'\n", os.Args[getgopt.Optind]) + } After parsing a flag the ``Getopt()`` function returns true if there are still more flags to parse, or false if there are none more. This means that we can use it in a ``for`` or ``while`` loop to @@ -68,27 +68,33 @@ is ``':'`` and otherwise it will be ``'?'``. The *optstring* is a string passed as the 3rd argument to ``Getopt()`` which specified which flags you want to be able to handle. Each flag you want to handle is given as a single character in the string in any order. For example if you want to support the ``-a``, ``-b``, and ``-x`` flags you can -do:: +do: - getgopt.Getopt(len(os.Args), os.Args, "abx", &opt) - /* or */ - getgopt.Getopt(len(os.Args), os.Args, "bxa", &opt) +.. code-block:: go + + getgopt.Getopt(len(os.Args), os.Args, "abx", &opt) + /* or */ + getgopt.Getopt(len(os.Args), os.Args, "bxa", &opt) If you want a flag to take an argument, you should suffix the character with a ``':'``. So using the -above example, if we want the ``-b`` flag to take an argument, we could write:: +above example, if we want the ``-b`` flag to take an argument, we could write: + +.. code-block:: go - getgopt.Getopt(len(os.Args), os.Args, "ab:x", &opt) + getgopt.Getopt(len(os.Args), os.Args, "ab:x", &opt) Finally, by default the ``Getopt()`` function will print diagnostic error messages to standard output when the user fails to provide an argument to a flag that expects one or passes an invalid flag. If you would like to not have these diagnostics printed you can either prefix the optstring with ``':'`` or you can set the ``Opterr`` global variable to ``false``. Both of the following are -equivalent:: +equivalent: + +.. code-block:: go - getgopt.Getopt(len(os.Args), os.Args, ":ab:x", &opt) - /* or */ - getgopt.Opterr = false - getgopt.Getopt(len(os.Args), os.Args, "ab:x", &opt) + getgopt.Getopt(len(os.Args), os.Args, ":ab:x", &opt) + /* or */ + getgopt.Opterr = false + getgopt.Getopt(len(os.Args), os.Args, "ab:x", &opt) There is a *slight* difference in behavior though which was explained above. |