Make low level table sets error out on nil key, and change API test to expect same. Fixes #20

Author: milochristiansen

api_test.go

@@ -213,7 +213,12 @@ func TestTable(t *testing.T) {
 	assert(t, l.AbsIndex(-1) == 0, "Items remain on stack after all values popped.")
 
 	// Make sure nil is not a valid key
-	assert(t, !f(nil), "Nil acting as valid key.")
+	err := l.Protect(func() {
+		f2(nil, nil)
+	})
+	if err == nil {
+		t.Error("Setting nil key does not raise error.")
+	}
 
 	// And finally do some equivalent key tests
 	assert(t, f2(1, 1.0), "Equivalent keys failing. (1, 1.0)")

table.go

@@ -29,6 +29,8 @@ package lua
 import "math"
 import "runtime"
 
+import "github.com/milochristiansen/lua/luautil"
+
 // Set to 0 for zero based table indexing. This is only partly tested!
 var TableIndexOffset = 1
 
@@ -239,7 +241,7 @@ func (tbl *table) existsInt(k int64) bool {
 func (tbl *table) SetRaw(k, v value) {
 	switch idx := k.(type) {
 	case nil:
-		return
+		luautil.Raise("Cannot set nil table index.", luautil.ErrTypGenRuntime)
 	case float64:
 		if math.IsNaN(idx) {
 			return