grp : {1_'(&x=*x)_ x:",",x}
pos : {:[3=l:#p:&"-"=x;0,p@1;2=l;p;0=*p;,0;0,p]}
conv: 0${(x;1_ y)}/'{(pos x)_ x}'
expd: {,/@[x;&2=#:'x;{(*x)+!1+,/-':x}]}
rnge: {expd@conv grp x}