This is an implementation of the Boyer-Moore Majority Vote Algorithm for Copilot, which solves the majority vote problem in linear time and constant memory in two passes. majority implements the first pass, and aMajority the second pass. For details of the Boyer-Moore Majority Vote Algorithm see the following papers:

• Wim H. Hesselink, "The Boyer-Moore Majority Vote Algorithm", 2005
• Robert S. Boyer and J Strother Moore, "MJRTY - A Fast Majority Vote Algorithm", 1981

In addition, An Introduction to Copilot and copilot-discussion explain a form of this code in section 4.

For instance, with four streams passed to majority, and the candidate stream then passed to aMajority:

vote1:       vote2:       vote3:       vote4:       majority:    aMajority:
0            0            0            0            0            true
1            0            0            0            0            true
1            1            0            0            1            false
1            1            1            0            1            true
1            1            1            1            1            true

For other examples, see examples/Voting.hs in the Copilot repository.