Robot's automatic argument conversion (#2890) makes it possible to have a keywords like

def accept_list(arg: list):
    ...

def accept_dict(arg: dict):
    ...

and call them so that argument are Python literals

Accept List    ['list', 'items', 'here']
Accept Dict    {'key': 'value', 'another': 'item'}

This is pretty convenient, but needing to use Python syntax is a bit ugly in general and especially annoying when using embedded arguments that are supposed to enhance readability:

Select animals ['cat', 'dog'] from list

I propose we enhance argument conversion so that we support also the following syntax:

Accept List    list, items, here
Accept Dict    key=value, another=item

The high level semantics would be as follows:

• Separator between items is a comma and a space. This allows using commas in values like first, second,with,commas, third. Having a comma followed by a space in the value wouldn't be possible.
• We could allow using a semicolon and a space as an alternative separator. In that case we'd use the separator that's encountered first. This would allow usages like first; second, with, commas followed by spaces; third.
• With dictionaries the separator between key and value is =. This is the syntax we use also when creating &{dict} variables.
• Values are considered strings by default. This can be changed by using generics (Convert and validate collection contents when using generics in type hints #4433) and TypedDict (Convert and validate TypedDict items #4477).
• Because this would be handled by type convertors, variables would have been resolved already earlier. That means that something like ${1}, ${2} wouldn't create a list of integers. See the above point for alternatives.
• Also escapes are handled before type conversion. That makes it impossible to use something like first, second\,with\,commas for escaping commas in values.

This enhancement would ease using collections a lot especially if #4433 and #4477 are implemented. If we agree above semantics are fine, implementation would also be pretty easy. I thus add this to RF 5.1 scope even though the release is already late.