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%
% OVAR.htex

The domain \spadtype{OrderedVariableList} provides symbols
which are restricted to a particular list and have a definite
ordering. Those two features are specified by a \spadtype{List Symbol}
object that is the argument to the domain.
\xtc{
This is a sample ordering of three symbols.
}{
\spadcommand{ls:List Symbol:=['x,'a,'z] \bound{ls}}
}
\xtc{
Let's build the domain
}{
\spadcommand{Z:=OVAR ls \bound{Z} \free{ls}}
}
\xtc{
How many variables does it have?
}{
\spadcommand{size()\$Z \free{Z}}
}
\xtc{
They are (in the imposed order)
}{
\spadcommand{lv:=[index(i::PI)\$Z for i in 1..size()\$Z] \bound{lv}\free{Z}}
}
\xtc{
Check that the ordering is right
}{
\spadcommand{sorted?(>,lv) \free{lv}}
}
