Constant functions¶

class
sage.misc.constant_function.
ConstantFunction
¶ Bases:
sage.structure.sage_object.SageObject
A class for function objects implementing constant functions.
EXAMPLES:
sage: f = ConstantFunction(3) sage: f The constant function (...) > 3 sage: f() 3 sage: f(5) 3
Such a function could be implemented as a lambda expression, but this is not (currently) picklable:
sage: g = lambda x: 3 sage: g == loads(dumps(g)) Traceback (most recent call last): ... PicklingError: Can't pickle ...: attribute lookup ... failed sage: f == loads(dumps(f)) True
Also, in the long run, the information that this function is constant could be used by some algorithms.
Todo
 Should constant functions have unique representation?
 Should the number of arguments be specified in the input?
 Should this go into
sage.categories.maps
? Then what should be the parent (e.g. forlambda x: True
)?