Position of a node

Hi Goodman.

Does the penman library have a method to return the position of each node in the graph? Ex. (w / want-01 :ARG0 (b / boy) :ARG1 (g / go-01 : ARG0 b)) want-01 - 0 boy - 0.0 go-01 - 0.1

[goodmami]

Ok, I’ve reconsidered this and changed Tree.positions() to Tree.walk() which yields paths to branches. That is, it should yield one pair for every branch in the tree structure. This is still not exactly the same as the alignment annotations, but this is more general and should be able to be applied to alignment annotation conversion. Here’s an example:

>>> import penman
>>> t = penman.parse('''
... # ::tok I swam in the lake .
... (s / swim-01~e.1
...    :ARG0 (i / i~e.0)
...    :location~e.2 (l / lake~e.4))''')
>>> for path, branch in t.walk():
...     print(path, branch)
... 
(0,) ('/', 'swim-01~e.1')
(1,) (':ARG0', ('i', [('/', 'i~e.0')]))
(1, 0) ('/', 'i~e.0')
(2,) (':location~e.2', ('l', [('/', 'lake~e.4')]))
(2, 0) ('/', 'lake~e.4')

Note that the top node doesn’t have an index, because these are indices of branches. They are 0-based but the concept is included as a branch, so it looks like 1-based indices. Here’s an example of how you could get most of the way to the alignment metadata format:

>>> from penman.tree import is_atomic
>>> for path, branch in t.walk():
...     if is_atomic(branch[1]):
...         if path[-1] == 0:
...             path = path[:-1]
...         path = '.'.join(map(str, (1,) + path))
...         print(path, branch[1])
... 
1 swim-01~e.1
1.1 i~e.0
1.2 lake~e.4

To get the rest of the way would require parsing the alignment info from the roles or concepts. The AlignmentMarker.from_string() function would help here. Also one would need to consider role alignments on branches whose target is not atomic.

@rafaelanchieta does this look better?

[rafaelanchieta]

It’s great. I’ll close the issue.