Trying to write a simple ML program to reverse a list...
Here's what I got:
fun reversehelper nil L = L
| reversehelper (X::L1) L2 = (reversehelper L1 (X::L2))
| reversehelper (X::L3) nil = (reversehelper L3 [X])
fun myreverse List = reversehelper (List,
)
Then I open up my sml editor and type: use "hw1.sml";
and get this:
[opening hw1.sml]
hw1.sml:5.22-5.46 Error: operator and operand don't agree [tycon mismatch]
operation domain: 'Z list
operand: 'Y * 'X list
in expression:
reversehelper (List,nil)
uncaught exception Error
raised at: ../compiler/TopLevel/interact/evalloop.sml:63.48-63.57
../compiler/TopLevel/interact/evalloop.sml:44.54
../compiler/TopLevel/interact/evalloop.sml:291.17-291.20
I'm new to ML and have no idea what this means....