getRange method
Implementation
List<Konto> getRange(Map<String,String> minmax,{List<Konto>? passthrough} )
{
List<Konto> result = (passthrough != null)? passthrough:[];
String min =(minmax.containsKey("min"))?minmax["min"]!.trim():"0";
String max =(minmax.containsKey("max"))?minmax["max"]!.trim():"0";
//print("in getRange : $minmax, '$min'-'$max' from ${konten.keys}");
//select common part
int n =0;
while(min[n] == max[n]) n++;
String common = min.substring(0,n);
Konto parent = (get(common)==null)?Konto():get(common)!;
//print("common : $n=> '$common'; kto: ${parent.desc} ${parent.children.keys}");
parent.getRange(min.substring(n),max.substring(n),passthrough:result);
return result;
}