Tool for drawing parse trees? [closed]

Question

Does anyone have a good tool for drawing parse trees arising from a context-free grammar? There is this question, but it dealt specifically with finite automata instead of parse trees. I've been using graphviz, but it's kind of annoying to have to label each node individually etc.

Answer 1

You can use http://ironcreek.net/phpsyntaxtree/.

Example:

Input was:

[ROOT
  [S
    [S
      [NP [PRP It]]
      [VP [VBZ is]
        [NP
          [QP [RB nearly] [DT half] [JJ past] [CD five]]]]]
    [, ,]
    [S
      [NP [PRP we]]
      [VP [MD can] [RB not]
        [VP [VB reach]
          [NP [NN town]]
          [PP [IN before]
            [NP [NN dark]]]]]]
    [, ,]
    [S
      [NP [PRP we]]
      [VP [MD will]
        [VP [VB miss]
          [NP [NN dinner]]]]]
    [. .]]]

Also works if the string has no line breaks, e.g.:

[S [NP [DT The] [NN man]] [VP [VBZ is] [VP [VBG running] [PP [IN on] [NP [DT the] [NN mountain]]]]] [. .]]

Answer 2

If you have a well-written context-free grammar(CFG) then you can draw the tree diagram simply by using nltk library.

import nltk
#defining Contex Free Grammar
grammar = nltk.CFG.fromstring("""
  S  -> NP VP
  NP -> Det Nom | PropN
  Nom -> Adj Nom | N
  VP -> V Adj | V NP | V S | V NP PP
  PP -> P NP
  PropN -> 'Buster' | 'Chatterer' | 'Joe'
  Det -> 'the' | 'a'
  N -> 'bear' | 'squirrel' | 'tree' | 'fish' | 'log'
  Adj  -> 'angry' | 'frightened' |  'little' | 'tall'
  V ->  'chased'  | 'saw' | 'said' | 'thought' | 'was' | 'put'
  P -> 'on'
  """)

sentence = 'the angry bear chased the frightened little squirrel'.split()
def parse(sent):
    #Returns nltk.Tree.Tree format output
    a = []  
    parser = nltk.ChartParser(grammar)
    for tree in parser.parse(sent):
        a.append(tree)
    return(a[0]) 

#Gives output as structured tree   
print(parse(sentence))

#Gives tree diagrem in tkinter window
parse(sentence).draw()

Structured tree output

Tree Diagram in Tkinter Window