5.3. spy.prelude

Utilities that are automatically imported during spy runs. Specfically, the CLI runs the equivalent of from builtins import *; from spy.prelude import * before it starts running user code.

spy.prelude.id(x)

Return x.

spy.prelude.exhaust(iterable)

Iterate over iterable for its side effects, returning nothing.

spy.prelude.ft(*args)

Return a tuple that, when called, calls all its members with the same argument.

spy.prelude.mt(*args)

Return a tuple that, when called, calls each of its members with corresponding arguments from the call:

$ spy '"abcde", [1,2,3]' -c 'mt(len, sum)'
(5, 6)

spy.prelude.sum(iterable, start=0)

Like the built-in sum, but written with generic usage in mind: this version accepts anything for which + is defined, and avoids quadratic behaviour where possible.

This depends on in-place addition’s being consistent with basic addition. The Python documentation does guarantee this, but some significant libraries don’t.

If start is not provided, spy’s sum will use iterable’s first element, if it has one. Thus -ac sum will normally just work.