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Getopt
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Method Getopt.find_option()
- Method
find_option
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string|int(0..1) Getopt.find_option(array(string) argv, array(string)|string shortform, array(string)|string|void longform, array(string)|string|void envvars, string|int(0..1)|void def, int|void throw_errors)
- Description
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This is a generic function to parse command line options of the
type -f, --foo or --foo=bar.
- Parameter argv
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The first argument should be the array of strings that was sent as
the second argument to your main() function.
- Parameter shortform
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The second is a string with the short form of your option. The
short form must be only one character long. It can also be an
array of strings, in which case any of the options in the array
will be accepted.
- Parameter longform
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This is an alternative and maybe more readable way to give the
same option. If you give "foo" as longform your program
will accept --foo as argument. This argument can also be
an array of strings, in which case any of the options in the
array will be accepted.
- Parameter envvars
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This argument specifies an environment variable that can be used
to specify the same option, to make it easier to customize
program usage. It can also be an array of strings, in which case
any of the mentioned variables in the array may be used.
- Parameter def
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This argument has two functions: It specifies if the option takes an
argument or not, and it informs find_option() what to return if the
option is not present. If def is given and the option does not have an
argument find_option() will fail. def can be specified as
UNDEFINED or left out if the option does not take an argument.
- Parameter throw_errors
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If throw_errors has been specified find_option() will
throw errors on failure. If it has been left out, or is
0 (zero), it will instead print an error message on
Stdio.stderr and exit the program with result code 1 on
failure.
- Returns
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Returns the value the option has been set to if any.
If the option is present, but has not been set to anything
1 will be returned.
Otherwise if any of the environment variables specified in envvars has
been set, that value will be returned.
If all else fails, def will be returned.
- Throws
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If an option that requires an argument lacks an argument and
throw_errors is set an error will be thrown.
- Note
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find_option() modifies argv . Parsed options will be removed
from argv . Elements of argv that have been removed entirely will
be replaced with zeroes.
This function reads options even if they are written after the first
non-option on the line.
Index 0 (zero) of argv is not scanned for options,
since it is reserved for the program name.
Only the first ocurrance of an option will be parsed. To parse
multiple ocurrances, call find_option() multiple times.
- See also
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Getopt.get_args()
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