camxes 0.2

Parsing Lojban

The parse() function returns a parse tree of named nodes.

>>> import camxes
>>> print camxes.parse("coi rodo")
text
 `- free
     +- CMAVO
     |   `- COI
     |       `- u'coi'
     `- sumti5
         +- CMAVO
         |   `- PA
         |       `- u'ro'
         `- CMAVO
             `- KOhA
                 `- u'do'

Turn a tree back into Lojban with the lojban property.

>>> camxes.parse("coi rodo!").lojban
u'coi ro do'

This joins the leaf nodes with a space, but you can preserve spaces and punctuation by passing spaces=True to parse().

>>> camxes.parse("coi rodo!", spaces=True).lojban
u'coi rodo!'

Child nodes can be accessed by name as attributes, giving a list of such nodes. If there are no child nodes with that name an exception is raised.

>>> print camxes.parse("coi rodo").free[0].sumti5[0].CMAVO[1]
CMAVO
 `- KOhA
     `- u'do'

You can also access nodes by sequential position without giving the name.

>>> print camxes.parse("coi rodo")[0][1]
sumti5
 +- CMAVO
 |   `- PA
 |       `- u'ro'
 `- CMAVO
     `- KOhA
         `- u'do'

Nodes iterate over their children.

>>> list(camxes.parse("coi rodo")[0][1])
[<CMAVO {ro}>, <CMAVO {do}>]

They also know their name.

>>> camxes.parse("coi rodo")[0][1].name
u'sumti5'

Verifying grammatical validity

parse() is able to parse some ungrammatical input by processing as much as is grammatical. It is therefore unreliable for checking if some text is grammatical. For this purpose, there is the isgrammatical() predicate.

>>> camxes.isgrammatical("coi rodo")
True
>>> camxes.isgrammatical("mupli cu fliba")
False
>>> print camxes.parse("mupli cu fliba")
text
 `- BRIVLA
     `- gismu
         `- u'mupli'

Deconstructing compound words into affixes

decompose() gives you the affixes and hyphens of a compound.

>>> camxes.decompose("genturfa'i")
(u'gen', u'tur', u"fa'i")

It will complain for input that is not a single, valid compound.

>>> camxes.decompose("camxes")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid compound 'camxes'

Parsing only morphology

The morphology() function works much like parse().

>>> print camxes.morphology("coi")
text
 `- CMAVO
     `- COI
         +- c
         |   `- u'c'
         +- o
         |   `- u'o'
         `- i
             `- u'i'

Tree traversal

Search for nodes with the find() method. It takes any number of arguments that are wildcard-matched against node names. This operation recurses down each branch until a match is found, but does not search children of matching nodes.

>>> camxes.parse("coi rodo").find('sumti*')
(<sumti5 {ro do}>,)

>>> camxes.parse("coi rodo").find('PA', 'KOhA')
(<PA {ro}>, <KOhA {do}>)

Key access on nodes is a shortcut for the first match of a find.

>>> camxes.parse("la camxes genturfa'i fi la lojban")['cmene']
<cmene {camxes}>

The leafs property is a tuple of all leaf nodes, which should be the unicode lexemes.

>>> camxes.parse("coi rodo").leafs
(u'coi', u'ro', u'do')

The branches() method finds the parents of nodes whose leafs match the arguments. This lets you search for the branches a sequence of lexemes belong to.

>>> camxes.parse("lo ninmu cu klama lo tcadu").branches("lo")
(<sumti6 {lo ninmu}>, <sumti6 {lo tcadu}>)
>>> camxes.parse("lo ninmu cu klama lo tcadu").branches("ninmu")
(<sumti6 {lo ninmu}>,)
>>> camxes.parse("lo ninmu cu klama lo tcadu").branches("klama", "lo", "tcadu")
(<sentence {lo ninmu cu klama lo tcadu}>,)

A generalization of these is called filter() and takes a predicate function that decides if a node should be listed. filter() is a generator so we use list() here to see the results.

>>> leafparent = lambda node: not isinstance(node[0], camxes.Node)
>>> list(camxes.parse("coi rodo").filter(leafparent))
[<COI {coi}>, <PA {ro}>, <KOhA {do}>]

Tree transformation

You can transform a node, recursively, into a tuple of strings, where the first item is the name of the node and the rest are the child nodes. This property is called primitive and can be useful if you’re serializing a parse tree to a more “dumb” format such as JSON.

>>> from pprint import pprint
>>> pprint(camxes.parse("coi rodo").primitive)
(u'text',
 (u'free',
  (u'CMAVO', (u'COI', u'coi')),
  (u'sumti5', (u'CMAVO', (u'PA', u'ro')), (u'CMAVO', (u'KOhA', u'do')))))

>>> import json
>>> print json.dumps(camxes.parse("coi").primitive, indent=2)
[
  "text",
  [
    "CMAVO",
    [
      "COI",
      "coi"
    ]
  ]
]

The generalization of primitive is called map() and takes a transformer function that in turn takes a node. The transformation is then mapped recursively on all nodes and a nested tuple, similar to that of primitive, is returned.

>>> camxes.parse("coi rodo").map(len)
(1, (2, (1, (1, 3)), (2, (1, (1, 2)), (1, (1, 2)))))