Using subs() with tuples doesn't work when called as a method

[DonSheddow]

@syms x, y, z
ex = x + y + z
ex.subs((x, 1), (y, pi))

should return 1 + pi + z, but it returns x + y + z. Similarly, ex.subs((x, 1)) throws an error.

If you write subs(ex, (x, 1), (y, pi)) instead, it works as expected. I think the method call doesn't dispatch to the correct implementation, so the only method call that works is ex.subs(var, replacement), but I'm not that familiar with Julia, so I'm not sure.

If it's not possible to fix this, the documentation at https://docs.juliahub.com/SymPy/KzewI/1.1.4/introduction/#Substitution-1 should be changed to use the subs(ex, (x, 1), (y, pi)) style instead, and maybe add a note that the method-call syntax doesn't work with tuples.

Thanks for working on this library, it's awesome! :)

[jverzani]

Thanks, that is a documentation error. The underlying sympy call would need to be

ex.subs([(x, 1), (y, PI)])

(the tuples are in some container and not just part of the variadic arguments. The subs(ex, ...) is a julia interface which makes this a bit more natural (in my opinion).