def eval_comp(context, comp, expected_type):
"""
Instantiate the given component, computing
the required config.
:type context: ctx.EvaluationContext
:param context: Evaluation context.
:type comp: ast.Component
:param comp: the node to evaluate.
:type expected_type: type_util.IsType
:param expected_type: The expected type of this computation.
:return: Returns the instantiated component.
"""
arguments = {}
# Compute arguments
for arg in comp.args:
arg_name = ast.DotPath(arg.arg_name.span, arg.arg_name, [])
arg_value = eval_rhs(context, arg.value, expected_type[arg_name])
arguments[arg.arg_name.inner_val()] = arg_value
# Lookup component
component_type = introspect.get_class_by_name(comp.type_name.val)
# Get default config for the component
conf = component_type.get_default_config()
# Update modified params
for k, val in arguments.iteritems():
conf[k] = val
# Delay evaluation until we do the assign
return component_type, conf
def action_dot_path(s, l, t):
# First token is the name of the variable
# The rest is the property path
if isinstance(t[0], ast.StringLit) and len(t[1:]) == 0:
return t[0]
return ast.DotPath(ast.make_span(s, l, t), t[0], t[1:])