Test cases for proper call parsing.

sdr> /program = Program.C4;
C4
sdr> ///
sdr> /// simple examples
sdr> /parse("trade")
trade
sdr> /parse("trade and roll")
and roll(trade)
sdr> /parse("do half of a trade and roll")
and roll(_half(trade))
sdr> /parse('do half of a trade twice')
_fractional(2, _half(trade))
sdr> /parse('do half of a trade twice and roll')
and roll(_fractional(2, _half(trade)))
sdr> ///
sdr> /// precedence levels
sdr> /parse("trade twice and roll")
and roll(_fractional(2, trade))
sdr> /parse("trade and roll twice")
_fractional(2, and roll(trade))
sdr> /parse("boys roll the girls away")
_roll away(BOY, GIRL)
sdr> /// tandem binds looser than 'roll'; if you want
sdr> /// something else, call "tandem trade and invidually roll"
sdr> ///  or "tandem trade ; roll"
sdr> /parse("tandem trade and roll")
tandem(and roll(trade))
sdr> /parse("tandem trade and individually roll")
and individually roll(tandem(trade))
sdr> /parse("tandem roll")
tandem(roll)
sdr> ///
sdr> /// "anyone anything" concept
sdr> /parse("centers square thru and roll")
anyone while others(CENTER, and roll(_full_square_thru), nothing)
sdr> /parse("centers centers run")
anyone while others(CENTER, run(CENTER), nothing)
sdr> ///
sdr> /// tricky roll away examples
sdr> /parse("centers roll away")
anyone while others(CENTER, roll away, nothing)
sdr> /parse("centers roll the ends away")
_roll away(CENTER, END)
sdr> /parse("centers centers roll the ends away")
anyone while others(CENTER, _roll away(CENTER, END), nothing)
sdr> ///
sdr> /// precedence of <anyone> <anything> -vs- roll
sdr> /parse("centers trade while the ends trade and roll")
anyone while others(CENTER, trade, and roll(trade))
sdr> ///
sdr> /// precedence of 'down the middle and ...'
sdr> /parse("sides down the middle")
down the middle(SIDE, nothing)
sdr> /parse("heads down the middle and as couples touch 1/4")
down the middle(HEAD, as couples(_touch(1/4)))
sdr> ///
sdr> /// precedence of mirror
sdr> /parse("mirror tandem trade")
mirror(tandem(trade))
sdr> ///
sdr> /// precedence of mirror -vs- left
sdr> /parse("left swing thru and roll")
and roll(left(swing thru))
sdr> /parse("mirror swing thru and roll")
mirror(and roll(swing thru))
sdr> ///
sdr> /// trade down the line:
sdr> /parse('boys trade down the line')
trade down the line(BOY)
sdr> /// the "anyone while others" call has a special case to make
sdr> /// "boys trade" equivalent to "boys trade down the line"
sdr> /parse('boys trade')
anyone while others(BOY, trade, nothing)
sdr> ///
sdr> /// precedence of "as couples" vs roll
sdr> /parse('as couples trade and roll')
as couples(and roll(trade))
sdr> /// XXX: as couples swing and mix?
sdr> /exit