Allow negative numbers as optional optional arguments and command arguments when unambiguous

[shadowspawn]

Problem

It is unexpected when negative numbers don't work as option-arguments or command arguments and require special treatment.

e.g.

test --optional -3 => test --optional=-3
test -12.4 => test -- -12.4

See: #61 #413 #2338

Solution

Allow negative numbers for optional option-arguments and for command arguments.

Like Python, if there are options with digit short flag then don't treat negative numbers as special since they overlap with some options. Keep the behaviour simple and conservative.

Description of what some other libraries do: pkgjs/parseargs#77 (comment)

• yargs has support for negative numbers
• Python allows negative numbers for positionals if there are not options that look like negative numbers (Python Arguments containing -)

ChangeLog

• add: support for negative numbers as option-arguments and command-arguments

[mmkal]

Looks good to me! FYI I opened a small PR which could either complement this, or become unnecessary if this gets in, or go in first if it's less controversial - I don't feel strongly: #2341

[shadowspawn]

Moved out of draft, ready for review.