#!/usr/bin/env python

# -*- coding: utf-8 -*-

# java2python.compiler.template -> Base classes for writing Python source.

#

# This module defines templates -- chunks of Python source code --

# that can be easily manipulated and written. Each class provides

# string methods (__str__, dump, dumps) for serializing instances as a

# source code string.

#

# The Factory class is used to to provide runtime lookup of concrete

# classes; this was necessary to accommodate splitting the behavior of

# the compiler subpackage into multiple modules. So-called patterns

# are usually a sign of a bad design and/or language limitations, and

# this case is no exception.

from cStringIO import StringIO

from functools import partial

from itertools import chain, ifilter, imap

from java2python.lang import tokens

from java2python.lib import FS, colors

class Factory(object):

""" Factory -> creates pre-configured callables for new block instances.

Both templates and visitors use an instance of this class as a simple

interface to create new blocks like this:

stat = self.factory.statement()

The `__getattr__` method does the work of looking up and returning

the appropriate block class. The lookup depends on the types

registry, which is populated by the FactoryTypeDetector metaclass

below.

One important thing to realize regarding this factory is this:

when an attribute is requested (`self.factory.expr` for example),

the factory locates the type and returns a constructor for it with

the config object pre-applied.

"""

types = {}

def __init__(self, config):

self.config = config

def __getattr__(self, name):

try:

return partial(self.types[name], self.config)

except (KeyError, ):

raise AttributeError('Factory missing "{0}" type.'.format(name))

class FactoryTypeDetector(type):

""" FactoryTypeDetector -> detects factory-creatable types as they are defined.

As subclasses are created they are checked for an attribute called

`factoryName`. If present, that key is used to populate the

type registry in the Factory class.

Note that the actual subclasses are not created here (templates and

visitors do not specify a `factoryName`). Actual factory types are created

in `java2python.compiler.block`. This is because we're after not

templates or visitors, but rather visitors combined with templates (aka

blocks). Refer to the `blocks` module for the specific factory

type names.

"""

def __init__(cls, name, bases, namespace):

try:

Factory.types[cls.factoryName] = cls

except (AttributeError, ):

pass

class Base(object):

""" Base -> base class for formatting Python output.

This class defines a large set of attributes and methods for the

other concrete templates defined below. The items defined here

can be grouped as follows:

* References

This class defines `bases`, `children`, `decorators`, etc. for

tracking the relationship between this instance and other blocks.

* Type Information

This class defines many is-A properties, such as isClass,

isModule, isVoid, etc. Subclasses typically override one or more

of these with an attribute or property.

* Configuration

This class provides utility methods for retrieving values from the

runtime configuration. See the definition of `configHandler` and

`configHandlers` for details.

* Serialization

This class provides a default implementation for subclasses to

serialize their instances as Python source code strings. Notably,

the `__str__` method is provided, which in turn defers most of its

work to the `dumps` method. Subclasses provide different

implementations of these methods where needed.

Also, the `__repr__` method is defined by this class for printing

a the template as tree for debugging.

"""

__metaclass__ = FactoryTypeDetector

isAnnotation = isClass = isComment = isEnum = isExpression = \

isInterface = isMethod = isModule = isStatement = False

def __init__(self, config, name=None, type=None, parent=None):

self.bases = []

self.children = []

self.config = config

self.decorators = []

self.factory = Factory(config)

self.modifiers = []

self.name = name

self.parameters = []

self.parent = parent

self.type = type

self.variables = []

if parent:

parent.children.append(self)

def __repr__(self):

""" Returns the debug string representation of this template. """

name = colors.white('name:') + colors.cyan(self.name) if self.name else ''

parts = [colors.green(self.typeName), name]

if self.type:

parts.append(colors.white('type:') + colors.cyan(self.type))

if self.modifiers:

parts.append(colors.white('modifiers:') + colors.cyan(','.join(self.modifiers)))

return ' '.join(parts)

def __str__(self):

""" Returns the Python source code representation of this template. """

handlers = self.configHandlers('Output')

return reduce(lambda v, func:func(self, v), handlers, self.dumps(-1))

def adopt(self, child, index=-1):

""" Adds child to this objecs children and sets the childs parent. """

self.children.insert(index, child)

child.parent = self

def altIdent(self, name):

""" Returns an alternate identifier for the one given. """

for klass in self.parents(lambda v:v.isClass):

if name in klass.variables:

try:

method = self.parents(lambda v:v.isMethod).next()

except (StopIteration, ):

return name

if name in [p['name'] for p in method.parameters]:

return name

if name in method.variables:

return name

return ('cls' if method.isStatic else 'self') + '.' + name

return name

def configHandler(self, part, suffix='Handler', default=None):

""" Returns the config handler for this type of template. """

name = '{0}{1}{2}'.format(self.typeName, part, suffix)

return self.config.last(name, default)

def configHandlers(self, part, suffix='Handlers'):

""" Returns config handlers for this type of template """

name = '{0}{1}{2}'.format(self.typeName, part, suffix)

return imap(self.toIter, self.config.last(name, ()))

def dump(self, fd, level=0):

""" Writes the Python source code for this template to the given file. """

indent, isNotNone = level * self.indent, lambda x:x is not None

lineFormat = '{0}{1}\n'.format

for line in ifilter(isNotNone, self.iterPrologue()):

line = lineFormat(indent, line)

fd.write(line if line.strip() else '\n')

for item in ifilter(isNotNone, self.iterHead()):

item.dump(fd, level+1)

for item in self.iterBody():

item.dump(fd, level+1)

for line in ifilter(isNotNone, self.iterEpilogue()):

line = lineFormat(indent, line)

fd.write(line if line.strip() else '\n')

def dumps(self, level=0):

""" Dumps this template to a string. """

fd = StringIO()

self.dump(fd, level)

return fd.getvalue()

def dumpRepr(self, fd, level=0):

""" Writes a debug string for this template to the given file. """

indent, default = self.indent, lambda x, y:None

fd.write('{0}{1!r}\n'.format(indent*level, self))

for child in ifilter(None, self.children):

getattr(child, 'dumpRepr', default)(fd, level+1)

@property

def indent(self):

""" Returns the indent string for this item. """

return self.config.last('indentPrefix', ' ')

@property

def isPublic(self):

""" True if this item is static. """

return 'public' in self.modifiers

@property

def isStatic(self):

""" True if this item is static. """

return 'static' in self.modifiers

@property

def isVoid(self):

""" True if this item is void. """

return 'void' == self.type

def iterPrologue(self):

""" Yields the items in the prologue of this template. """

return chain(*(h(self) for h in self.configHandlers('Prologue')))

def iterHead(self):

""" Yields the items in the head of this template. """

items = chain(*(h(self) for h in self.configHandlers('Head')))

return imap(self.toExpr, items)

def iterBody(self):

""" Yields the items in the body of this template. """

return iter(self.children)

def iterEpilogue(self):

""" Yields the items in the epilogue of this template. """

return chain(*(h(self) for h in self.configHandlers('Epilogue')))

def makeParam(self, name, type, **kwds):

""" Creates a parameter as a mapping. """

param = dict(name=name, type=type)

if 'default' in kwds:

param['default'] = kwds['default']

return param

def parents(self, pred=lambda v:True):

""" Yield each parent in the family tree. """

while self:

if pred(self):

yield self

self = self.parent

def find(self, pred=lambda v:True):

""" Yield each child in the family tree. """

for child in self.children:

if pred(child):

yield child

if hasattr(child, 'find'):

for value in child.find(pred):

yield value

@property

def className(self):

""" Returns the name of the class of this item. """

return self.__class__.__name__

@property

def typeName(self):

""" Returns the name of this template type. """

return self.className.lower()

def toExpr(self, value):

""" Returns an expression for the given value if it is a string. """

try:

return self.factory.expr(left=value+'')

except (TypeError, ):

return value

def toIter(self, value):

""" Returns an iterator for the given value if it is a string. """

try:

value + ''

except (TypeError, ):

return value

else:

def wrapper(*a, **b):

yield value

return wrapper

class Expression(Base):

""" Expression -> formatting for Python expressions. """

isExpression = True

def __init__(self, config, left='', right='', fs=FS.lr, parent=None, tail=''):

super(Expression, self).__init__(config, parent=parent)

self.left, self.right, self.fs, self.tail = left, right, fs, tail

def __repr__(self):

""" Returns the debug string representation of this template. """

parts, parent, showfs = [colors.blue(self.typeName)], self.parent, True

if isinstance(self.left, (basestring, )) and self.left:

parts.append(colors.white('left:') + colors.yellow(self.left))

showfs = False

if isinstance(self.right, (basestring, )) and self.right:

parts.append(colors.white('right:') + colors.yellow(self.right))

showfs = False

if self.modifiers:

parts.append(colors.white('modifiers:') + colors.cyan(','.join(self.modifiers)))

if self.type:

parts.append(colors.white('type:') + colors.cyan(self.type))

if showfs:

parts.append(colors.white('format:') + colors.yellow(self.fs))

if self.tail:

parts.append(colors.white('tail:') + colors.black(self.tail))

return ' '.join(parts)

def __str__(self):

""" Returns the Python source code representation of this template. """

return self.fs.format(left=self.left, right=self.right) + self.tail

def dump(self, fd, level=0):

""" Writes the Python source code for this template to the given file. """

line = '{0}{1}\n'.format(self.indent*level, self)

fd.write(line if line.strip() else '\n')

def dumpRepr(self, fd, level=0):

""" Writes a debug string for this template to the given file. """

fd.write('{0}{1!r}\n'.format(self.indent*level, self))

for obj in (self.left, self.right):

dumper = getattr(obj, 'dumpRepr', lambda x, y:None)

dumper(fd, level+1)

@property

def isComment(self):

""" True if this expression is a comment. """

try:

return self.left.strip().startswith('#')

except (AttributeError, ):

return False

class Comment(Expression):

""" Comment -> formatting for Python comments. """

isComment = True

def __repr__(self):

""" Returns the debug string representation of this comment. """

parts = [colors.white(self.typeName+':'),

colors.black(self.left) + colors.black(self.right) + colors.black(self.tail), ]

return ' '.join(parts)

class Statement(Base):

""" Statement -> formatting for Python statements. """

isStatement = True

def __init__(self, config, keyword, fs=FS.lr, parent=None):

super(Statement, self).__init__(config, parent=parent)

self.keyword = keyword

self.expr = self.factory.expr(left=keyword, fs=fs)

self.expr.parent = self

def __repr__(self):

""" Returns the debug string representation of this statement. """

parts = [colors.green(self.typeName), colors.white('keyword:')+colors.cyan(self.keyword)]

return ' '.join(parts)

def iterPrologue(self):

""" Yields the keyword (and clause, if any) for this statement . """

yield self.expr

class Module(Base):

""" Module -> formatting for Python modules. """

isModule = True

def iterBody(self):

""" Yields the items in the body of this template. """

blank, prev = self.factory.expr(), None

for child in super(Module, self).iterBody():

if prev and not prev.isComment:

yield blank

if prev and prev.isClass and child and child.isClass:

yield blank

yield child

prev = child

class ClassMethodSharedMixin(object):

""" ClassMethodSharedMixin -> shared methods for Class and Method types. """

def iterPrologue(self):

""" Yields the items in the prologue of this template. """

prologue = super(ClassMethodSharedMixin, self).iterPrologue()

return chain(prologue, self.decorators, self.iterDecl())

class Class(ClassMethodSharedMixin, Base):

""" Class -> formatting for Python classes. """

isClass = True

def iterBases(self):

""" Yields the base classes for this type. """

return chain(*(h(self) for h in self.configHandlers('Base')))

def iterDecl(self):

""" Yields the declaration for this type. """

bases = ', '.join(self.iterBases())

bases = '({0})'.format(bases) if bases else ''

yield 'class {0}{1}:'.format(self.name, bases)

def iterBody(self):

""" Yields the items in the body of this template. """

def sprinkleBlanks(body):

blank, prev = self.factory.expr(), None

for item in body:

if prev:

if type(prev) != type(item) and not prev.isComment:

yield blank

elif item.isMethod and prev.isMethod:

yield blank

elif prev.isClass:

yield blank

yield item

prev = item

for handler in self.configHandlers('PostWalk'):

handler(self)

head = any(self.iterHead())

body = list(super(Class, self).iterBody())

tail = () if (body or head) else [self.factory.expr(left='pass')]

body = () if tail else sprinkleBlanks(body)

return chain(body, tail)

class Annotation(Class):

""" Annotation -> formatting for annotations converted to Python classes. """

isAnnotation = True

def __init__(self, config, name=None, type=None, parent=None):

super(Annotation, self).__init__(config, name, type, parent)

class Enum(Class):

""" Enum -> formatting for enums converted to Python classes. """

isEnum = True

class Interface(Class):

""" Interface -> formatting for interfaces converted to Python classes. """

isInterface = True

class MethodContent(Base):

""" MethodContent -> formatting for content within Python methods. """

class Method(ClassMethodSharedMixin, Base):

""" Method -> formatting for Python methods. """

isMethod = True

def __init__(self, config, name=None, type=None, parent=None):

super(Method, self).__init__(config, name, type, parent)

self.parameters.append(self.makeParam('self', 'object'))

def iterParams(self):

""" Yields the parameters of this method template. """

return chain(*(h(self) for h in self.configHandlers('Param')))

def iterDecl(self):

""" Yields the declaration for this method template. """

def formatParam(p):

if 'default' in p:

return '{0}={1}'.format(p['name'], p['default'])

return p['name']

params = ', '.join(formatParam(param) for param in self.iterParams())

yield 'def {0}({1}):'.format(self.name, params)

def iterBody(self):

""" Yields the items in the body of this method template. """

head = any(self.iterHead())

body = list(super(Method, self).iterBody())

tail = () if (body or head) else [self.factory.expr(left='pass')]

return chain(body, tail)