added first working pieces of compiler
--HG--
branch : trunk
diff --git a/jinja2/compiler.py b/jinja2/compiler.py
new file mode 100644
index 0000000..330db56
--- /dev/null
+++ b/jinja2/compiler.py
@@ -0,0 +1,380 @@
+# -*- coding: utf-8 -*-
+"""
+ jinja2.compiler
+ ~~~~~~~~~~~~~~~
+
+ Compiles nodes into python code.
+
+ :copyright: Copyright 2008 by Armin Ronacher.
+ :license: GNU GPL.
+"""
+from random import randrange
+from operator import xor
+from cStringIO import StringIO
+from jinja2 import nodes
+from jinja2.visitor import NodeVisitor, NodeTransformer
+from jinja2.exceptions import TemplateAssertionError
+
+
+operators = {
+ 'eq': '==',
+ 'ne': '!=',
+ 'gt': '>',
+ 'gteq': '>=',
+ 'lt': '<',
+ 'lteq': '<=',
+ 'in': 'in',
+ 'notin': 'not in'
+}
+
+
+def generate(node, filename, stream=None):
+ is_child = node.find(nodes.Extends) is not None
+ generator = CodeGenerator(is_child, filename, stream)
+ generator.visit(node)
+ if stream is None:
+ return generator.stream.getvalue()
+
+
+class Identifiers(object):
+ """Tracks the status of identifiers in frames."""
+
+ def __init__(self):
+ # variables that are known to be declared (probably from outer
+ # frames or because they are special for the frame)
+ self.declared = set()
+
+ # names that are accessed without being explicitly declared by
+ # this one or any of the outer scopes. Names can appear both in
+ # declared and undeclared.
+ self.undeclared = set()
+
+ # names that are declared locally
+ self.declared_locally = set()
+
+ # names that are declared by parameters
+ self.declared_parameter = set()
+
+ def add_special(self, name):
+ """Register a special name like `loop`."""
+ self.undeclared.discard(name)
+ self.declared.add(name)
+
+ def is_declared(self, name):
+ """Check if a name is declared in this or an outer scope."""
+ return name in self.declared or name in self.declared_locally or \
+ name in self.declared_parameter
+
+ def find_shadowed(self):
+ """Find all the shadowed names."""
+ return self.declared & (self.declared_locally | self.declared_parameter)
+
+
+class Frame(object):
+
+ def __init__(self, parent=None):
+ self.identifiers = Identifiers()
+ self.parent = parent
+ if parent is not None:
+ self.identifiers.declared.update(
+ parent.identifiers.declared |
+ parent.identifiers.undeclared |
+ parent.identifiers.declared_locally |
+ parent.identifiers.declared_parameter
+ )
+
+ def inspect(self, nodes):
+ """Walk the node and check for identifiers."""
+ visitor = FrameIdentifierVisitor(self.identifiers)
+ for node in nodes:
+ visitor.visit(node)
+
+ def inner(self):
+ """Return an inner frame."""
+ return Frame(self)
+
+
+class FrameIdentifierVisitor(NodeVisitor):
+ """A visitor for `Frame.inspect`."""
+
+ def __init__(self, identifiers):
+ self.identifiers = identifiers
+
+ def visit_Name(self, node):
+ """All assignments to names go through this function."""
+ if node.ctx in ('store', 'param'):
+ self.identifiers.declared_locally.add(node.name)
+ elif node.ctx == 'load':
+ if not self.identifiers.is_declared(node.name):
+ self.identifiers.undeclared.add(node.name)
+
+ def visit_Macro(self, node):
+ """Macros set local."""
+ self.identifiers.declared_locally.add(node.name)
+
+ # stop traversing at instructions that have their own scope.
+ visit_Block = visit_Call = visit_FilterBlock = \
+ visit_For = lambda s, n: None
+
+
+class CodeGenerator(NodeVisitor):
+
+ def __init__(self, is_child, filename, stream=None):
+ if stream is None:
+ stream = StringIO()
+ self.is_child = is_child
+ self.filename = filename
+ self.stream = stream
+ self.blocks = {}
+ self.indentation = 0
+ self.new_lines = 0
+ self.last_identifier = 0
+ self._last_line = 0
+ self._first_write = True
+
+ def temporary_identifier(self):
+ self.last_identifier += 1
+ return 't%d' % self.last_identifier
+
+ def indent(self):
+ self.indentation += 1
+
+ def outdent(self):
+ self.indentation -= 1
+
+ def blockvisit(self, nodes, frame, force_generator=False):
+ self.indent()
+ if force_generator:
+ self.writeline('if 0: yield None')
+ for node in nodes:
+ self.visit(node, frame)
+ self.outdent()
+
+ def write(self, x):
+ if self.new_lines:
+ if not self._first_write:
+ self.stream.write('\n' * self.new_lines)
+ self._first_write = False
+ self.stream.write(' ' * self.indentation)
+ self.new_lines = 0
+ self.stream.write(x)
+
+ def writeline(self, x, node=None, extra=0):
+ self.newline(node, extra)
+ self.write(x)
+
+ def newline(self, node=None, extra=0):
+ self.new_lines = max(self.new_lines, 1 + extra)
+ if node is not None and node.lineno != self._last_line:
+ self.write('# line: %s' % node.lineno)
+ self.new_lines = 1
+ self._last_line = node.lineno
+
+ def pull_locals(self, frame, no_indent=False):
+ if not no_indent:
+ self.indent()
+ for name in frame.identifiers.undeclared:
+ self.writeline('l_%s = context[%r]' % (name, name))
+ if not no_indent:
+ self.outdent()
+
+ # -- Visitors
+
+ def visit_Template(self, node, frame=None):
+ assert frame is None, 'no root frame allowed'
+ self.writeline('from jinja2.runtime import *')
+ self.writeline('filename = %r' % self.filename)
+ self.writeline('context = TemplateContext(global_context, '
+ 'make_undefined, filename)')
+
+ # generate the body render function.
+ self.writeline('def body(context=context):', extra=1)
+ frame = Frame()
+ frame.inspect(node.body)
+ self.pull_locals(frame)
+ self.blockvisit(node.body, frame, True)
+
+ # top level changes to locals are pushed back to the
+ # context of *this* template for include.
+ self.indent()
+ self.writeline('context.from_locals(locals())')
+ self.outdent()
+
+ # at this point we now have the blocks collected and can visit them too.
+ for name, block in self.blocks.iteritems():
+ block_frame = Frame()
+ block_frame.inspect(block.body)
+ self.writeline('def block_%s(context=context):' % name, block, 1)
+ self.pull_locals(block_frame)
+ self.blockvisit(block.body, block_frame, True)
+
+ def visit_Block(self, node, frame):
+ """Call a block and register it for the template."""
+ if node.name in self.blocks:
+ raise TemplateAssertionError("the block '%s' was already defined" %
+ node.name, node.lineno,
+ self.filename)
+ self.blocks[node.name] = node
+ self.writeline('for event in block_%s():' % node.name)
+ self.indent()
+ self.writeline('yield event')
+ self.outdent()
+
+ def visit_Extends(self, node, frame):
+ """Calls the extender."""
+ self.writeline('extends(', node, 1)
+ self.visit(node.template)
+ self.write(', globals())')
+
+ def visit_For(self, node, frame):
+ loop_frame = frame.inner()
+ loop_frame.inspect(node.iter_child_nodes())
+ loop_frame.identifiers.add_special('loop')
+ extended_loop = bool(node.else_) or \
+ 'loop' in loop_frame.identifiers.undeclared
+
+ # make sure we "backup" overridden, local identifiers
+ # TODO: we should probably optimize this and check if the
+ # identifier is in use afterwards.
+ aliases = {}
+ for name in loop_frame.identifiers.find_shadowed():
+ aliases[name] = ident = self.temporary_identifier()
+ self.writeline('%s = l_%s' % (ident, name))
+
+ self.pull_locals(loop_frame, True)
+
+ self.newline(node)
+ if node.else_:
+ self.writeline('l_loop = None')
+ self.write('for ')
+ self.visit(node.target, loop_frame)
+ self.write(extended_loop and ', l_loop in looper(' or ' in ')
+ self.visit(node.iter, loop_frame)
+ self.write(extended_loop and '):' or ':')
+ self.blockvisit(node.body, loop_frame)
+
+ if node.else_:
+ self.writeline('if l_loop is None:')
+ self.blockvisit(node.else_, loop_frame)
+
+ # reset the aliases and clean them up
+ for name, alias in aliases.iteritems():
+ self.writeline('l_%s = %s; del %s' % (name, alias, alias))
+
+ def visit_If(self, node, frame):
+ self.writeline('if ', node)
+ self.visit(node.test, frame)
+ self.write(':')
+ self.blockvisit(node.body, frame)
+ if node.else_:
+ self.writeline('else:')
+ self.blockvisit(node.else_, frame)
+
+ def visit_ExprStmt(self, node, frame):
+ self.newline(node)
+ self.visit(node, frame)
+
+ def visit_Output(self, node, frame):
+ self.newline(node)
+
+ # try to evaluate as many chunks as possible into a static
+ # string at compile time.
+ body = []
+ for child in node.nodes:
+ try:
+ const = unicode(child.as_const())
+ except:
+ body.append(child)
+ continue
+ if body and isinstance(body[-1], list):
+ body[-1].append(const)
+ else:
+ body.append([const])
+
+ # if we have less than 3 nodes we just yield them
+ if len(body) < 3:
+ for item in body:
+ if isinstance(item, list):
+ self.writeline('yield %s' % repr(u''.join(item)))
+ else:
+ self.newline(item)
+ self.write('yield unicode(')
+ self.visit(item, frame)
+ self.write(')')
+
+ # otherwise we create a format string as this is faster in that case
+ else:
+ format = []
+ arguments = []
+ for item in body:
+ if isinstance(item, list):
+ format.append(u''.join(item).replace('%', '%%'))
+ else:
+ format.append('%s')
+ arguments.append(item)
+ self.writeline('yield %r %% (' % u''.join(format))
+ idx = -1
+ for idx, argument in enumerate(arguments):
+ if idx:
+ self.write(', ')
+ self.visit(argument, frame)
+ self.write(idx == 0 and ',)' or ')')
+
+ def visit_Name(self, node, frame):
+ # at this point we should only have locals left as the
+ # blocks, macros and template body ensure that they are set.
+ self.write('l_' + node.name)
+
+ def visit_Const(self, node, frame):
+ val = node.value
+ if isinstance(val, float):
+ # XXX: add checks for infinity and nan
+ self.write(str(val))
+ else:
+ self.write(repr(val))
+
+ def binop(operator):
+ def visitor(self, node, frame):
+ self.write('(')
+ self.visit(node.left, frame)
+ self.write(' %s ' % operator)
+ self.visit(node.right, frame)
+ self.write(')')
+ return visitor
+
+ def uaop(operator):
+ def visitor(self, node, frame):
+ self.write('(' + operator)
+ self.visit(node.node)
+ self.write(')')
+ return visitor
+
+ visit_Add = binop('+')
+ visit_Sub = binop('-')
+ visit_Mul = binop('*')
+ visit_Div = binop('/')
+ visit_FloorDiv = binop('//')
+ visit_Pow = binop('**')
+ visit_Mod = binop('%')
+ visit_And = binop('and')
+ visit_Or = binop('or')
+ visit_Pos = uaop('+')
+ visit_Neg = uaop('-')
+ visit_Not = uaop('not ')
+ del binop, uaop
+
+ def visit_Compare(self, node, frame):
+ self.visit(node.expr, frame)
+ for op in node.ops:
+ self.visit(op, frame)
+
+ def visit_Operand(self, node, frame):
+ self.write(' %s ' % operators[node.op])
+ self.visit(node.expr, frame)
+
+ def visit_Subscript(self, node, frame):
+ self.write('subscript(')
+ self.visit(node.node, frame)
+ self.write(', ')
+ self.visit(node.arg, frame)
+ self.write(')')