shithub: mc

ref: a2ef6bfcd8de0ae9f7f2df2fcdd692bde6ea422c
dir: /lib/iter/test/perm.myr/

use std
use testr

use iter

const main = {
	testr.run([
		[.name = "byperm-01", .fn = byperm01],
		[.name = "byperm-02", .fn = byperm02],
		[.name = "byperm-03", .fn = byperm03],
		[.name = "byperm-04", .fn = byperm04],
	][:])
}

const byperm01 = {c
	var v : int[:] = [ 0, 2, 1 ][:]
	var sb : std.strbuf# = std.mksb()
	std.sbfmt(sb, " ")

	for w : iter.byperm(v, std.numcmp)
		std.sbfmt(sb, "{} ", w)
	;;

	var expected : byte[:] = " [0, 1, 2] [0, 2, 1] [1, 0, 2] [1, 2, 0] [2, 0, 1] [2, 1, 0] "
	var actual : byte[:] = std.sbfin(sb)
	testr.check(c, std.eq(expected, actual), "expected “{}”, got “{}”", expected, actual)
}

const byperm02 = {c
	var v : int[:] = [ 1, 1 ][:]
	var sb : std.strbuf# = std.mksb()
	std.sbfmt(sb, " ")

	for w : iter.byperm(v, std.numcmp)
		std.sbfmt(sb, "{} ", w)
	;;

	var expected : byte[:] = " [1, 1] "
	var actual : byte[:] = std.sbfin(sb)
	testr.check(c, std.eq(expected, actual), "expected “{}”, got “{}”", expected, actual)
}

const byperm03 = {c
	var v : int[:] = [ 3, 1, 1 ][:]
	var sb : std.strbuf# = std.mksb()
	std.sbfmt(sb, " ")

	for w : iter.byperm(v, std.numcmp)
		std.sbfmt(sb, "{} ", w)
	;;

	var expected : byte[:] = " [1, 1, 3] [1, 3, 1] [3, 1, 1] "
	var actual : byte[:] = std.sbfin(sb)
	testr.check(c, std.eq(expected, actual), "expected “{}”, got “{}”", expected, actual)
}

const byperm04 = {c
	var v : int[:] = [ 0, 3, 1, 1 ][:]
	var nperm = 0

	for w : iter.byperm(v, std.numcmp)
		nperm++
	;;
	
	/*
	  There are 24 permutations for 4 elements, but we get only
	  half because two elements are equal.
	*/
	const expected = 12
	testr.check(c, std.eq(expected, nperm), "expected “{}”, got “{}”", expected, nperm)
}