I guess mutable is more consistent with the rest of the api (things like rect IIRC)
2009/5/1 Lorenz Quack <d...@amberfisharts.com>: > Hi > > as a follow up to the "API draft for vector type" I would like to discuss > the merits of having a mutable or immutable vector type. > > > Arguments for an immutable vector type: > > Brian Fisher pointed out two advantages of immutable vector types: > 1) they prevent bugs in programs like the following (adopted from Brian): >> class Angel(object) >> def __init__(self, offset): >> self.offset = offset >> >> t = Angel() >> halo_pos = t.offset >> halo_pos.y -= 5 # BUG: this changes the offset in t > > 2) if vectors are immutable you can use them as keys in dicts > > > > Arguments for a mutable vector type: > > 1) operations such as rotate() and scale_to_length() are more elegant when > operation in-place. for immutable types you would have to do "v = > v.rotate()" or use a module level rotate function "v = > pygame.math.rotate_vector(v)" or something similar. > > 2) a priori I would expect mutable vectors to perform better than immutable > ones because you don't have to create new objects for every operation. > > > > So are there anymore arguments? > And where do people stand on this issue? > > > yours > > //Lorenz >
