任意の自然数の体積を持つ直方体の持ち得る自然数x, y, zの組み合わせを求めるEgisonシェル芸

gistfile1.sh

$ echo 64 | \
egison -T -m '1#(match-all (p-f %1) (multiset integer) [ <join $xs <join $ys $zs>> [(foldl * 1 xs) (foldl * 1 ys) (foldl * 1 zs)]])' | \
xargs -n 3 | \
egison -T -f '3#(and (lte? %1 %2) (lte? %2 %3))' | \
sort | uniq

# 結果 (体積64の直方体)
# 1       1       64
# 1       2       32
# 1       4       16
# 1       8       8
# 2       2       16
# 2       4       8
# 4       4       4

!/bin/sh

echo 64 |
egison -T -s '1#(match-all (p-f (car %1)) (multiset integer) [ <join $xs <join $ys $zs>> [(foldl * 1 xs) (foldl * 1 ys) (foldl * 1 zs)]])' |
egison -T -F1c -f '1#(all lte? (match-all %1 (list integer) [ <join _ <cons $x <cons $y _>>> [x y]]))' |
sort | uniq