a := "abcd" ----> "abcd"
a1 := a[1:2] ----> "a"
a
every write(!a1) ----> none
a2 := a[3:0] ----> "cd"
c
d
every write(!a2) ----> none
a3 := a[0:3] ----> "cd"
c
d
every write(!a3) ----> none
a4 := a[2:2] ----> ""
every write(!a4) ----> none
a5 := a[0-:2] ----> "cd"
c
d
every write(!a5) ----> none
Run-time error 101 at line 20 in expr43.icn
integer expected
offending value: "cd"