data.INTERVAL.MELODIC A token indicating direction of the interval but not its precise value, an indication of diatonic interval quality and size, or a decimal value in half steps. Decimal values are permitted to accommodate micro-tuning.
Module MEI
Used by
<rng:data type= "decimal"/>
<rng:data type= "token">
<rng:param name= "pattern"> u|d|s </rng:param>
<rng:data type= "token">
<rng:param name= "pattern"> (\+|\-)?[AdMmP][0-9]+ </rng:param>

MEI Guidelines Version 3.0.0