hchasestevens / show_ast

An IPython notebook plugin for visualizing ASTs.

showast

An IPython/Jupyter notebook plugin for visualizing abstract syntax trees.

Example usage

Examples can be found in this IPython notebook.

import showast

%%showast
print 1 + 2

from showast import show_source
import antigravity
show_source(antigravity)

Installation

pip install showast

showast has the following Python dependencies:

ipython
graphviz

You will also need to have Graphviz installed.

Use of the alternative nltk-based rendering engine requires the following packages:

nltk
pillow

When using this option, you will additionally need to have Ghostscript installed.

Contacts

• Name: H. Chase Stevens
• Twitter: @hchasestevens

show_ast's Issues

How to get the tree output as a data structure?

Is there any way of instead of printing the tree, extracting the tree as a data structure to iterate with?

Using SVG output in ipywidget.HTML?

Hi I'd like to use the SVG output generated by the graphviz renderer inside ipywidgets. I don't see yet, if there is a way to get direct access to the SVG, so I could use it like in the attached screenshot.

Requires DISPLAY

This would be a very useful utility (I'm teaching Programming Languages). But, when trying to use showast on a server (no DISPLAY is set) running JupyterHub you get this error:

---------------------------------------------------------------------------
TclError                                  Traceback (most recent call last)
<ipython-input-8-389e57529b45> in <module>()
----> 1 get_ipython().run_cell_magic('showast', '', '\n1 + 1')

/opt/anaconda3/lib/python3.5/site-packages/IPython/core/interactiveshell.py in run_cell_magic(self, magic_name, line, cell)
   2113             magic_arg_s = self.var_expand(line, stack_depth)
   2114             with self.builtin_trap:
-> 2115                 result = fn(magic_arg_s, cell)
   2116             return result
   2117 

/opt/anaconda3/lib/python3.5/site-packages/showast/__init__.py in showast(__, cell)
    154 def showast(__, cell):
    155     m = ast.parse(cell)
--> 156     show_ast(m)
    157 
    158 

/opt/anaconda3/lib/python3.5/site-packages/showast/__init__.py in show_ast(module)
    148     else:
    149         treestring = nltk_treestring(module)
--> 150     tree_image(treestring)
    151 
    152 

/opt/anaconda3/lib/python3.5/site-packages/showast/__init__.py in tree_image(tree)
    122 def tree_image(tree):
    123     t = Tree.fromstring(tree)
--> 124     tv = SizableTreeView(t)
    125     tv._cframe.print_to_file('.temp.ps')
    126     im = Image.open('.temp.ps')

/opt/anaconda3/lib/python3.5/site-packages/showast/__init__.py in __init__(self, *trees)
     86         self._trees = trees
     87 
---> 88         self._top = Tk()
     89 
     90         cf = self._cframe = CanvasFrame(self._top)

/opt/anaconda3/lib/python3.5/tkinter/__init__.py in __init__(self, screenName, baseName, className, useTk, sync, use)
   1866                 baseName = baseName + ext
   1867         interactive = 0
-> 1868         self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
   1869         if useTk:
   1870             self._loadtk()

TclError: no display name and no $DISPLAY environment variable

This seems like a roundabout way to get a graphical representation. Any ideas for a workaround?

BTW, an SVG would be preferable as an image format.