检查同步特征：特质/特质UI

Question

I'm sweeping through all the Traits in a large program, and many of our traits are synchronized. For example, consider HasTrait objects of the structure:

a = Material1.ShellMaterial
b = Material2.CoreMaterial
c = Material3.MaterialX

In our application, it turns out that a and c are synchronized traits. In other words, Material3.MaterialX is the same as Material1.ShellMaterial , and they have set using sync_trait() (HasTraits API) .

Is it possible to inspect a,b,c and dynamically determine that a and c are synchronized?

The goal is to plot all of these, but hide redundant plots from the user. Typical comparisons between these like a==c return False , despite these objects representing the same data.

Answer 1

As far as I know there is no official API that allows to inspect the synchronization state of traits.

Of course, you could simply call the sync_trait() method again to make sure that the traits are synchronized (or not synchronized, if you use remove=True ). As a result, you will know the synchronization state of the traits.

If you do not want to change the synchronization state, you have to rely on non-official API functions, which are not documented and possibly subject to change -- so use them at your own risk.

from traits.api import HasTraits, Float
class AA(HasTraits):
    a =Float()
class BB(HasTraits):
    b = Float()
aa = AA()
bb = BB()
aa.sync_trait("a", bb, "b")

# aa.a and bb.b are synchronized
# Now we use non-official API functions
info = aa._get_sync_trait_info()

synced = info.has_key("a") # True if aa.a is synchronized to some other trait
if synced:
    sync_info = info["a"] # fails if a is not a synchronized trait
    # sync_info is a dictionary which maps (id(bb),"b") to a tuple (wr, "b")
    # If you do not know the id() of the HasTraits-object and the name of
    # the trait, you have to loop through all elements of sync_info and
    # search for the entry you want...
    wr, name = sync_info[(id(bb), "b")]
    # wr is a weakref to the class of bb, and name is the name 
    # of the trait which aa.a is synced to
    cls = wr() # <__main__.BB at 0x6923a98>

Again, use at your own risk, but it works for me.