{NAME}{S}*-= {s(ASSIGNMENT);prefix="<minus>";c();BEGIN(R);}
{NAME}{S}*= {s(ASSIGNMENT);c();BEGIN(R);}
<R>{ /* values which appear only on the right-hand side of assignments, like: x=50% */
{NAME}{S}*-= {s(ASSIGNMENT);prefix="<minus>";c();BEGIN(R);}
{NAME}{S}*= {s(ASSIGNMENT);c();BEGIN(R);}
<R>{ /* values which appear only on the right-hand side of assignments, like: x=50% */