Piecewise function that corresponds to the SBML piecewice definition
function piecewise input Real[:] value "Input values in the form {value1,value2,...,valueN,valueN+1}."; input Boolean[:] condition "Input conditions in the form {condition1,condition2,...,conditionN}. Not more than one condition is allowed to be true at any given time."; output Real y "Output value selected from the list of inputs."; end piecewise;