Better pretty printing for ASDL's own AST.

This will help with generating code to support reflection over ASDL
types.

asdl/asdl_.py

@@ -19,6 +19,7 @@
# [1] "The Zephyr Abstract Syntax Description Language" by Wang, et. al. See
#     http://asdl.sourceforge.net/
#-------------------------------------------------------------------------------
import cStringIO
import re

__all__ = [
@@ -94,39 +95,59 @@ def __repr__(self):
# See the EBNF at the top of the file to understand the logical connection
# between the various node types.

# TODO:
# - Add id type -- or should it be py(id) or something?

builtin_types = {'string', 'int', 'bool'}

class AST:
    def __repr__(self):
    def Print(self, f, indent):
        raise NotImplementedError

    def __repr__(self):
        f = cStringIO.StringIO()
        self.Print(f, 0)
        return f.getvalue()


class Module(AST):
    def __init__(self, name, dfns):
        self.name = name
        self.dfns = dfns
        self.types = {type.name: type.value for type in dfns}

    def __repr__(self):
        return 'Module({0.name}, {0.dfns})'.format(self)
    def Print(self, f, indent):
        ind = indent * '  '
        f.write('%sModule %s {\n' % (ind, self.name))

        for d in self.dfns:
          d.Print(f, indent+1)
          f.write('\n')
        f.write('%s}\n' % ind)


class Type(AST):
    def __init__(self, name, value):
        self.name = name
        self.value = value

    def __repr__(self):
        return 'Type({0.name}, {0.value})'.format(self)
    def Print(self, f, indent):
        ind = indent * '  '
        f.write('%sType %s {\n' % (ind, self.name))
        self.value.Print(f, indent+1)
        f.write('%s}\n' % ind)


class Constructor(AST):
    def __init__(self, name, fields=None):
        self.name = name
        self.fields = fields or []

    def __repr__(self):
        return 'Constructor({0.name}, {0.fields})'.format(self)
    def Print(self, f, indent):
        ind = indent * '  '
        f.write('%sConstructor %s {\n' % (ind, self.name))

        for field in self.fields:
          field.Print(f, indent+1)
        f.write('%s}\n' % ind)


class Field(AST):
    def __init__(self, type, name=None, seq=False, opt=False):
@@ -135,39 +156,52 @@ def __init__(self, type, name=None, seq=False, opt=False):
        self.seq = seq
        self.opt = opt

    def __repr__(self):
    def Print(self, f, indent):
        extra = []
        if self.seq:
            extra = ", seq=True"
            extra.append('seq=True')
        elif self.opt:
            extra = ", opt=True"
            extra.append('opt=True')
        else:
            extra = ""
        if self.name is None:
            return 'Field({0.type}{1})'.format(self, extra)
        else:
            return 'Field({0.type}, {0.name}{1})'.format(self, extra)

        ind = indent * '  '
        f.write('%sField %s %s' % (ind, self.name, self.type))
        if extra:
          f.write('(')
          f.write(', '.join(extra))
          f.write(')')
        f.write('\n')


class Sum(AST):
    def __init__(self, types, attributes=None):
        self.types = types
        self.attributes = attributes or []

    def __repr__(self):
    def Print(self, f, indent):
        ind = indent * '  '
        f.write('%sSum {\n' % ind)
        for t in self.types:
          t.Print(f, indent+1)
        if self.attributes:
            return 'Sum({0.types}, {0.attributes})'.format(self)
        else:
            return 'Sum({0.types})'.format(self)
          f.write('%s\n' % self.attributes)
        f.write('%s}\n' % ind)


class Product(AST):
    def __init__(self, fields, attributes=None):
        self.fields = fields
        self.attributes = attributes or []

    def __repr__(self):
    def Print(self, f, indent):
        ind = indent * '  '
        f.write('%sProduct {\n' % ind)
        for field in self.fields:
          field.Print(f, indent+1)
        if self.attributes:
            return 'Product({0.fields}, {0.attributes})'.format(self)
        else:
            return 'Product({0.fields})'.format(self)
          f.write('%s\n' % self.attributes)
        f.write('%s}\n' % ind)

# A generic visitor for the meta-AST that describes ASDL. This can be used by
# emitters. Note that this visitor does not provide a generic visit method, so a

asdl/format.py

@@ -315,7 +315,6 @@ def MakeTree(obj, abbrev_hook=None, omit_empty=True):
  else:
    # Id uses this now.  TODO: Should we have plugins?  Might need it for
    # color.
    #print('OTHER', obj.__class__, isinstance(obj, py_meta.CompoundObj))
    return _ColoredString(repr(obj), _OTHER_TYPE)

  return out_node

asdl/gen_python.py

@@ -1,6 +1,10 @@
#!/usr/bin/python
"""
gen_python.py

Generate Python code from and ASDL schema.

TODO: What about Id?  app_types?
"""

import sys