fish-shell/share/functions/contains_seq.fish

function contains_seq --description 'Return true if array contains a sequence'
    set -l printnext
    switch $argv[1]
        case --printnext
            set printnext[1] 1
            set -e argv[1]
    end
    set -l pattern
    set -l string
    set -l dest pattern
    for i in $argv
        if test "$i" = --
            set dest string
            continue
        end
        set $dest $$dest $i
    end
    set -l nomatch 1
    set -l i 1
    for s in $string
        if set -q printnext[2]
            return 0
        end
        if test "$s" = "$pattern[$i]"
            set -e nomatch[1]
            set i (math i + 1)
            if not set -q pattern[$i]
                if set -q printnext[1]
                    set printnext[2] 1
                    continue
                end
                return 0
            end
        else
            if not set -q nomatch[1]
                set nomatch 1
                set i 1
            end
        end
    end
    if set -q printnext[1]
        echo ''
    end
    set -q printnext[2]
end