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bc.py
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bc.py
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import operator
import jsobject as jsType
from jsparser import parse, opTypeNames as assignOpMap, assignOps, tokens, Node
class ExpressionGenerator(object):
def __call__(self, node):
return getattr(self, node.type)(node)
def _binary_op(self, node, bc):
return (
self(node[0])
+ self(node[1])
+ [bc]
)
def IDENTIFIER(self, node):
return [('LOAD_VAR', node.value)]
def PLUS(self, node):
return self._binary_op(node, ('CALC_BINARY', node.type))
MINUS = MUL = DIV = MOD = PLUS
def GROUP(self, node):
return self(node[0])
def AND(self, node):
return self._binary_op(node, ('BOOL_OP', node.type))
OR = AND
def EQ(self, node):
return self._binary_op(node, ('COMP', node.type))
NE = STRICT_EQ = STRICT_NE = LT = LE = GT = GE = EQ
#constants
def NUMBER(self, node):
return [('LOAD_CONST', jsType.Number(node.value))]
def TRUE(self, node):
return [('LOAD_CONST', jsType.Boolean(True))]
def FALSE(self, node):
return [('LOAD_CONST', jsType.Boolean(False))]
def INCREMENT(self, node):
postfix = getattr(node, 'postfix', False)
return [
('LOAD_VAR', node[0].value),
('LOAD_CONST', jsType.Integer(1)),
('CALC_BINARY', 'PLUS'),
('STORE', node[0].value)
]
def ARRAY_INIT(self, node):
if len(node) > 0:
bc = reduce(operator.add, map(self, node[::-1]))
else:
bc = []
return bc + [('CREATE_ARRAY', len(node))]
LIST = ARRAY_INIT
def PROPERTY_INIT(self, node):
key = node[0]
def OBJECT_INIT(self, node):
print node
def FUNCTION(self, node):
bc = []
params = node.params
for param in params[::-1]:
bc.append(('LOAD_CONST', jsType.String(param)))
bc.append(('CREATE_ARRAY', len(params)))
bc.append(('NEW_FUNC', getattr(node, 'name', None)))
bcg = BytecodeGenerator()
body = bcg(node.body)
if not body or body[-1][0] != 'RETURN':
body.extend([
('LOAD_CONST', jsType.Undefined()),
('RETURN', None)
])
bc.append(('JUMP', len(body)))
bc.extend(body)
return bc
def ASSIGN(self, node):
name = node[0].value
#get right side
bc = self(node[1])
#is += etc.?
if node[0].assignOp:
op = assignOpMap[tokens[node[0].assignOp]]
bc = [('LOAD_VAR', name)] + bc + [('CALC_BINARY', op)]
return bc + [('STORE', name)]
def CALL(self, node):
return (
self(node[1])
+ self(node[0])
+ [('CALL', None )]
)
class ConditionGenerator(object):
def __init__(self):
self._expression = ExpressionGenerator()
def IF(self, node):
bc = self._expression(node.condition)
then = to_bytecode(node.thenPart)
else_ = self.ELSE(node.elsePart)
#1 for jump instruction of then block
bc.append(('JUMP_ON_FALSE', len(then)+1) )
bc.extend(then)
bc.append(('JUMP', len(else_)))
bc.extend(else_)
return bc
def ELSE(self, node):
if node is None:
return []
elif node.type == 'BLOCK':
return to_bytecode(node)
elif node.type == 'IF':
return self.IF(node)
class BytecodeGenerator(object):
def __init__(self, main=False):
self.bytecode = []
self._expression = ExpressionGenerator()
self.main = main
self.clean = False
self._condition = ConditionGenerator()
def expression(self, node):
bc = self._expression(node)
self.bytecode.extend(bc)
def var(self, node):
self.bytecode.append(('DECLARE', node.name))
if hasattr(node, 'initializer'):
self.bytecode.extend(
self._expression(node.initializer)
)
self.bytecode.append(('STORE', node.name))
else:
self.clean = True
def return_(self, node):
if isinstance(node.value, Node):
self.bytecode.extend(self._expression(node.value))
else:
self.bytecode.append(('LOAD_CONST', jsType.Undefined()))
self.bytecode.append(('RETURN', None))
def if_(self, node):
self.bytecode.extend(self._condition.IF(node))
def while_(self, node):
body = to_bytecode(node.body)
bc = self._expression(node.condition)
bc.append(('JUMP_ON_FALSE', len(body)+1) )
for i, code in enumerate(body):
if code[0] == 'CONTINUE' and code[1] is None:
body[i] = ('JUMP', -(i+len(bc)+1))
elif code[0] == 'BREAK':
body[i] = ('JUMP', len(body)-i)
#make it a loop
body.append(('JUMP', -(len(body)+len(bc)+1)))
bc.extend(body)
self.bytecode.extend(bc)
def for_(self, node):
setup = []
if node.setup:
setup = to_bytecode([node.setup])
condition = self._expression(node.condition)
body = to_bytecode(node.body)
update = self._expression(node.update)
condition.append(('JUMP_ON_FALSE',
len(body)+len(update)+1) )
for i, code in enumerate(body):
if code[0] == 'CONTINUE' and code[1] is None:
body[i] = ('JUMP', len(body)-i-1)
elif code[0] == 'BREAK':
body[i] = ('JUMP', len(body)+len(update)-i)
body.extend(update)
#make it a loop
body.append(('JUMP', -(len(body)+len(condition)+1)))
self.bytecode.extend(setup + condition + body)
def continue_(self, node):
self.bytecode.append(('CONTINUE', None))
def break_(self, node):
self.bytecode.append(('BREAK', None))
def __call__(self, nodes):
for node in nodes:
self.clean = False
if node.type == 'SEMICOLON':
self.expression(node.expression)
elif node.type == 'VAR':
map(self.var, node)
elif node.type in {'FUNCTION'}:
self.expression(node)
elif node.type == 'RETURN':
self.return_(node)
self.clean = True
elif node.type == 'WHILE':
self.while_(node)
self.clean = True
elif node.type == 'FOR':
self.for_(node)
self.clean = True
elif node.type == 'IF':
self.if_(node)
self.clean = True
elif node.type == 'CONTINUE':
self.continue_(node)
self.clean = True
elif node.type == 'BREAK':
self.break_(node)
self.clean = True
# else:
# print 'x', node
if not self.clean:
self.bytecode.append(('POP_STACK', None))
if self.main:
self.bytecode.append(('END', None))
return self.bytecode
to_bytecode = lambda xs: BytecodeGenerator()(xs)
if __name__ == '__main__':
from pprint import pprint
with open('example.js') as fobj:
instructions = parse(fobj.read())
bcg = BytecodeGenerator(True)
bytecode = bcg(instructions)
# pprint(bytecode)
from interpreter import Interpreter
ip = Interpreter()
ip.execute(bytecode)
# print 'locals', ip.namespace.locals