def compile_if(context, ast):
# compile the condition
assert (isinstance(ast, ast_objects.If))
compile_any(context, ast.condition)
# add true
t = context.register_constant(objects.Boolean(True))
context.emit(bytecode.LOAD_CONST, t)
# compare the condition to true
context.emit(bytecode.BINARY_EQ, bytecode.NO_ARG)
# condition:
# jump if zero (false): false block
# true block
# jump to end
# false block
# TODO: let jump target labels, not values! store the name of the jump
# in a constant and then reference that constant name, which can contain the
# jump position and be updated if need be
context.emit(bytecode.JUMP_IF_ZERO, 0)
# make a note of the instruction we'll have to change
false_jump = len(context.instructions) - 1
# then add the true block
compile_any(context, ast.body)
# then a jump from the true block to after the false block
context.emit(bytecode.JUMP, 0)
# the start of the false block is the current length
false_block = len(context.instructions)
# so set the false block jump to that point
context.instructions[false_jump] = (context.instructions[false_jump][0],
false_block)
compile_any(context, ast.else_body)
# get the point we're at now
after_false = len(context.instructions)
# then change the true jump to point here
context.instructions[false_block - 1] = (context.instructions[false_block -
1][0],
after_false)
def compile_while(context, ast):
assert(isinstance(ast, ast_objects.While))
condition_pos = len(context.instructions)
compile_any(context, ast.condition)
# add true
t = context.register_constant(objects.Boolean(True))
context.emit(bytecode.LOAD_CONST,t)
# compare the condition to true
context.emit(bytecode.BINARY_EQ,bytecode.NO_ARG)
# condition:
# jump if zero (false): after the block
# block
# jump to condition
# this will point to after the end
context.emit(bytecode.JUMP_IF_ZERO,0)
# make a note of the instruction we'll have to change
false_jump = len(context.instructions) - 1
compile_any(context,ast.body)
context.emit(bytecode.JUMP,condition_pos)
after_block = len(context.instructions)
context.instructions[false_jump] = (context.instructions[false_jump][0],after_block)
def compile_boolean(context, ast):
assert(isinstance(ast,ast_objects.Boolean))
value = objects.Boolean(ast.value)
index = context.register_constant(value)
context.emit(bytecode.LOAD_CONST,index)
def interpret(self, byte_code, args=[]):
pc = 0 # program counter
stack = []
variables = [objects.Null()] * 255
assert (len(args) == len(byte_code.arguments))
# print "(running %s)" % byte_code.name
# copy args into inner context
for i in range(0, len(args)):
# TODO: this doesn't make sense, indexes change I think?
# Make sure these aren't getting overwritten
index = byte_code.arguments[i]
# print "(arg %s going into %s)" % (args[i].dump(),index)
byte_code.variables[index] = objects.Variable("arg", args[i])
self.last_bc += byte_code.dump(True)
while pc < len(byte_code.instructions):
# the type of instruction and arg (a tuple)
opcode, arg = byte_code.instructions[pc]
# print "(%s %s %s)" % (pc, bytecode.reverse[opcode], arg)
# then increment
pc += 1
if opcode == bytecode.LOAD_CONST:
# grab a value from our constants and add to stack
value = byte_code.constants[arg]
stack.append(value)
elif opcode == bytecode.LOAD_VARIABLE:
var = byte_code.variables[arg]
assert (isinstance(var, objects.Variable))
# print "- appending value %s" % var.value.dump()
stack.append(var.value)
elif opcode == bytecode.STORE_VARIABLE:
value = stack.pop()
oldvar = byte_code.variables.get(arg, None)
if isinstance(oldvar, objects.Variable):
byte_code.variables[arg] = objects.Variable(
oldvar.name, value)
else:
byte_code.variables[arg] = objects.Variable("arg", value)
stack.append(value)
elif opcode == bytecode.STORE_ARRAY:
values = []
for i in range(arg):
values.append(stack.pop())
stack.append(objects.Array(values))
elif opcode == bytecode.STORE_DICT:
values = objects.r_dict(objects.dict_eq, objects.dict_hash)
for i in range(arg):
values[stack.pop()] = stack.pop()
stack.append(objects.Dict(values))
elif opcode == bytecode.PRINT:
value = stack.pop()
print(value.to_string())
stack.append(objects.Null())
elif opcode == bytecode.INDEX:
left = stack.pop()
right = stack.pop()
result = left.index(right)
stack.append(result)
elif opcode == bytecode.BINARY_ADD:
right = stack.pop()
left = stack.pop()
result = left.add(right)
stack.append(result)
elif opcode == bytecode.BINARY_SUB:
right = stack.pop()
left = stack.pop()
result = left.sub(right)
stack.append(result)
elif opcode == bytecode.BINARY_MUL:
right = stack.pop()
left = stack.pop()
result = left.mul(right)
stack.append(result)
elif opcode == bytecode.BINARY_DIV:
right = stack.pop()
left = stack.pop()
result = left.div(right)
stack.append(result)
elif opcode == bytecode.BINARY_NEQ:
right = stack.pop()
left = stack.pop()
result = left.equals(right)
result.boolvalue = not result.boolvalue
stack.append(result)
elif opcode == bytecode.BINARY_EQ:
right = stack.pop()
left = stack.pop()
result = left.equals(right)
stack.append(result)
elif opcode == bytecode.BINARY_GT:
right = stack.pop()
left = stack.pop()
result = left.gt(right)
stack.append(result)
elif opcode == bytecode.BINARY_GTE:
right = stack.pop()
left = stack.pop()
result = left.gte(right)
stack.append(result)
elif opcode == bytecode.BINARY_LT:
right = stack.pop()
left = stack.pop()
result = left.lt(right)
stack.append(result)
elif opcode == bytecode.BINARY_LTE:
right = stack.pop()
left = stack.pop()
result = left.lte(right)
stack.append(result)
elif opcode == bytecode.RETURN:
if arg == 1:
if len(stack) > 0:
result = stack.pop()
return result
return objects.Null()
elif opcode == bytecode.JUMP_IF_NOT_ZERO:
val = stack.pop()
assert (isinstance(val, objects.BaseBox))
result = val.equals(objects.Boolean(True))
assert (isinstance(result, objects.Boolean))
if result.value:
pc = arg
elif opcode == bytecode.JUMP_IF_ZERO:
val = stack.pop()
assert (isinstance(val, objects.BaseBox))
result = val.equals(objects.Boolean(True))
assert (isinstance(result, objects.Boolean))
if not result.value:
pc = arg
elif opcode == bytecode.JUMP:
pc = arg
elif opcode == bytecode.CALL:
assert (isinstance(byte_code.variables[arg], objects.Variable))
val = byte_code.variables[arg].value
if isinstance(val, objects.Function):
func = val.code
self.copy_context(byte_code, func)
args = []
if len(func.arguments) > len(stack):
raise Exception("Not enough arguments")
for i in range(0, len(func.arguments)):
args.append(stack.pop())
stack.append(self.interpret(func, args))
elif isinstance(val, objects.ExternalFunction):
# call
func = val.fn
arglen = val.args
args = []
for i in range(0, arglen):
args.append(stack.pop())
result = func(args)
stack.append(result)
else:
raise Exception("Not a function")
return stack[len(stack) - 1]
