 "Finding the start of a subsequence:"
 { $subsections
     subseq-start
+    subseq-start-from
     subseq-index
     subseq-index-from
     subseq-starts-at?

    }
}
{ $errors "Throws an error if the index is out of bounds." } ;

HELP: tail
{ $values { "seq" sequence } { "n" "a non-negative integer" } { "tailseq" "a new sequence" } }

{ $values { "n" "a start index" } { "seq" sequence } { "subseq" sequence } { "i/f" "a start index or " { $snippet "f" } } }
{ $description "Outputs the start index of the first contiguous subsequence equal to " { $snippet "subseq" } ", starting the search from the " { $snippet "n" } "th element. If no matching subsequence is found, outputs " { $link f } "." } ;

HELP: subseq-start-from
{ $values
    { "subseq" object } { "seq" sequence } { "n" integer }
    { "i/f" { $maybe integer } }
}
{ $description "Outputs the start index of the first contiguous subsequence equal to " { $snippet "subseq" } ", or " { $link f } " if no matching subsequence is found starting from " { $snippet "n" } "." } ;

HELP: subseq-start
{ $values { "subseq" sequence } { "seq" sequence } { "i/f" "a start index or " { $snippet "f" } } }
{ $description "Outputs the start index of the first contiguous subsequence equal to " { $snippet "subseq" } ", or " { $link f } " if no matching subsequence is found." } ;
