Author here, a good way to understand algebraic effects is as "resumeable exceptions." In this case the expected_value handler says to run `f ()` and whenever t

Author here, a good way to understand algebraic effects is as "resumeable exceptions." In this case the expected_value handler says to run `f ()` and whenever that computation "throws" a `flip ()` effect to handle it by resuming the computation with the value true returned for flip. The continuation continues as normal, subsequent uses of flip are also handled until the computation finishs. Then we evaluate the rest of `+ resume false) / 2.0` and resume the computation (a second time!) in the same place, this time with the value false. Finally, we add both values returned and divide by two to get the expected value. This way of computing expected value works because for each flip we essentially have a case-split: the value can be true or false with a 50-50 chance, so the expected value of the whole thing is is 0.5 * the result of the true branch + 0.5 * the result of the false branch! This is more of a fun use of effects than a practical one. If you're still curious about effects, check out the full page on them here: https://antelang.org/docs/language/#algebraic-effects https://antelang.org/docs/language/#algebraic-effects which includes some actually useful effects like State, Generators, looping constructs, parsers, etc.