def parse(expression):
output = ffi.new('char[{}]'.format(MAX_CHARS))
error = ffi.new('char[{}]'.format(ERROR_CHARS))
handler = calculate.parse(expression.encode(), error)
raise_if(decode(error))
calculate.variables(handler, output)
return Expression(expression, decode(output))
def evaluate(self, args):
size = len(args)
if size > 0:
args = [float(x) for x in args]
values = ffi.new('double[]', args)
else:
values = ffi.new('double *')
error = ffi.new('char[{}]'.format(ERROR_CHARS))
result = calculate.evaluate(self._handler, values, size, error)
raise_if(decode(error))
return result
def __init__(self, expression, variables=''):
if not isinstance(variables, str) and isinstance(variables, Iterable):
variables = ','.join(variables) if len(variables) > 0 else ''
error = ffi.new('char[{}]'.format(ERROR_CHARS))
self._handler = calculate.create(expression.encode(),
variables.encode(), error)
raise_if(decode(error))
def __getattr__(self, item):
try:
output = ffi.new('char[{}]'.format(MAX_CHARS))
if item not in self._properties:
raise KeyError
getattr(calculate, item)(self._handler, output)
output = decode(output)
if item == 'variables':
output = output.split(',') if output else []
return lambda: output
except KeyError:
raise AttributeError('{} object has no attribute {}'.format(
repr(self.__class__.__name__), repr(item)))