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The \spadtype{UniversalSegment} domain generalizes \spadtype{Segment}
by allowing segments without a ``hi'' end point.
\xtc{
}{
\spadcommand{pints  := 1..         \bound{pints}}
}
\xtc{
}{
\spadcommand{nevens := (0..) by -2 \bound{nevens}}
}
\xtc{
Values of type \spadtype{Segment} are automatically converted to
type \spadtype{UniversalSegment} when appropriate.
\exptypeindex{Segment}
}{
\spadcommand{useg: UniversalSegment(Integer) := 3..10 \bound{useg}}
}
\xtc{
The operation \spadfunFrom{hasHi}{UniversalSegment} is used to test
whether a segment has a \spad{hi} end point.
}{
\spadcommand{hasHi pints  \free{pints}}
}
\xtc{
}{
\spadcommand{hasHi nevens \free{nevens}}
}
\xtc{
}{
\spadcommand{hasHi useg   \free{useg}}
}
\xtc{
All operations available on type \spadtype{Segment} apply to
\spadtype{UniversalSegment}, with the proviso that expansions produce
streams rather than lists.
This is to accommodate infinite expansions.
}{
\spadcommand{expand pints \free{pints}}
}
\xtc{
}{
\spadcommand{expand nevens \free{nevens}}
}
\xtc{
}{
\spadcommand{expand [1, 3, 10..15, 100..]}
}

For more information on related topics,  see
\xmpref{Segment},
\xmpref{SegmentBinding},
\xmpref{List}, and
\xmpref{Stream}.
\showBlurb{UniversalSegment}
