ArgumentsOptions

ArgumentsOptions[f[args],n]
tries to separate args into a list of n positional arguments followed by a list of valid options for f.
ArgumentsOptions[f[args],{min,max}]
requires the number of positional arguments to be between min and max.
ArgumentsOptions[f[args],spec,assoc]
modifies the behavior based on the information in the association assoc.
Details

- ArgumentsOptions issues appropriate messages for f and returns a Failure object if f[…] has the wrong number of positional arguments, unknown options or invalid option specifications.
- The following keys can be used for the association assoc:
-
"ExtraOptions" {} additional options to treat as known options for f "OptionsMode" "Longest" how to interpret the optional positional arguments of args "Head" List wrapper for the positional arguments and options lists - Additional options given to "ExtraOptions" can be specified as rules nameval or as symbols func, which is equivalent to Options[func].
- ArgumentsOptions checks whether all options specified for f have valid names.
- The following values of "OptionsMode" can be used: »
-
"Longest" treat all trailing elements of args matching OptionsPattern[] as options for f "Shortest" treat anything other than one or more known options as positional arguments None treat all elements as positional arguments - Even with "OptionsMode""Shortest", an unknown option past position max still generates a message. »
- ArgumentsOptions has the attribute HoldFirst.
Examples
open allclose allBasic Examples (1)
Scope (7)
Separate the positional arguments and options for a function that takes between 1 and 3 positional arguments:
Require at least 2 positional arguments:
Calling f with 1 argument is invalid:

Require exactly 3 positional arguments:
Allow "hidden" options that do not appear in Options[f]:
The option a0 is not a known option for f:
Allow the option named hidden as well as any option of Graphics to be set:
Treat unknown trailing options in positions min+1 though max as positional arguments rather than options for f:
The rule b1 is treated as a positional argument:
With the default "OptionsMode""Longest", a message is issued for unknown options:

A known option is still treated as an option for f with "OptionsMode""Shortest":
Treat all elements as positional arguments rather than options for f:
Applications (2)
Define a function that calls a helper function if called with one or two positional arguments:
When called with one or two positional arguments, the helper function is called:
When called with more than two positional arguments, f returns unevaluated and issues a message:

Use "OptionsMode""Shortest" to treat trailing empty lists as positional arguments:
Properties & Relations (10)
ArgumentsOptions[f[…],…] issues a message and returns Failure[…] for invalid input to f:


If f does not accept options, all arguments are assumed to be positional:
Options are always returned as a flat list, irrespective of how they appeared in the input expression:
ArgumentsOptions[…,{min,max}] will always treat the first min arguments as positional:
Here, even though a0 matches OptionsPattern[], it is treated as a positional argument:
If the rule a0 is given after the positional arguments, it is treated as an option:
Only trailing options are considered when collecting options:
Trailing rules matching OptionsPattern[] are treated as options if they are known options for f:
This is true even if "OptionsMode""Shortest" is given:
An option specification that contains both known and unknown options generates a message:

In "OptionsMode""Shortest", a list with known and unknown options is treated as a positional argument if possible:
An unknown option past the maximum number of positional arguments still generates a message:

Only rules matching OptionsPattern[] can be valid option specifications:
The rule 12 does not match OptionsPattern[]:
Thus it is treated as a positional argument:
If 12 is given after the positional arguments, it is treated as an invalid option specification:

ArgumentsOptions returns Failure[…] when CheckArguments returns False:


Possible Issues (3)
If f accepts options, trailing empty lists are ignored by default because {} matches OptionsPattern[]:
Use "OptionsMode""Shortest" to treat a trailing empty list as a positional argument:
All arguments at or before the minimum argument count are considered positional arguments:
ArgumentsOptions does not check whether the option values are correct:
Infinity is not a valid value for Heads:

Text
Wolfram Research (2020), ArgumentsOptions, Wolfram Language function, https://reference.wolfram.com/language/ref/ArgumentsOptions.html (updated 2024).
CMS
Wolfram Language. 2020. "ArgumentsOptions." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2024. https://reference.wolfram.com/language/ref/ArgumentsOptions.html.
APA
Wolfram Language. (2020). ArgumentsOptions. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ArgumentsOptions.html