Support for PEP508

With PEP508 you can limit certain package to a specific platforms, e.g. waitress==1.0.2;platform_system=="Windows" to install waitress only on Windows.

It seem like poetry doesn’t support this feature at all or at least i wasn’t able to specify the constraint from above. Neither poetry add waitress==1.0.2;platform_system=="Windows" nor writing waitress = "=1.0.2;platform_system=Windows" to the pyproject.toml works.

[sdispater]

Thanks for your interest in Poetry!

As of now, neither the add command nor the pyproject.toml support PEP 508 when specifying dependencies. And while the pyproject.toml might support it in the future, the add command will most likely not.

The reason for it is that PEP 508 is not really readable when you have markers:

waitress==1.0.2;platform_system="Windows"

is, in my opinion, less readable than:

waitress = { version = "1.0.2", system = "Windows" }  # pyproject.tml

or for the add command:

poetry add waitress=1.0.2 --system Windows

Note that this is not yet supported but this is an idea of what one might expect in a near future for Poetry.

[sdispater]

@jacebrowning It should be fixed in the latest 0.10.0a2 prerelease.