feat: handle slice expressions

2 files changed, 19 insertions, 1 deletions

diff --git a/interp/interpreter.go b/interp/interpreter.go
index 8d372c3..4faba28 100644
--- a/interp/interpreter.go
+++ b/interp/interpreter.go
@@ -42,7 +42,8 @@ func (i *Interp) Eval(src string) (res reflect.Value, err error) {
 	i.Push(i.Data[dataOffset:]...)
 	i.PushCode(i.Code[codeOffset:]...)
 	if s, ok := i.Symbols["main"]; ok {
-		i.PushCode(vm.Instruction{Op: vm.Calli, Arg: []int{int(i.Data[s.Index].Int())}})
+		i.PushCode(vm.Instruction{Op: vm.Push, Arg: []int{int(i.Data[s.Index].Int())}})
+		i.PushCode(vm.Instruction{Op: vm.Call, Arg: []int{0}})
 	}
 	i.PushCode(vm.Instruction{Op: vm.Exit})
 	i.SetIP(max(codeOffset, i.Entry))
diff --git a/interp/interpreter_test.go b/interp/interpreter_test.go
index bf90357..7a974d1 100644
--- a/interp/interpreter_test.go
+++ b/interp/interpreter_test.go
@@ -230,6 +230,23 @@ func TestMap(t *testing.T) {
 	})
 }
 
+func TestSlice(t *testing.T) {
+	src0 := `s := []int{0, 1, 2, 3};`
+	run(t, []etest{
+		{src: src0 + `s`, res: `[0 1 2 3]`},                                  // #00
+		{src: src0 + `s[:]`, res: `[0 1 2 3]`},                               // #01
+		{src: src0 + `s[1:3]`, res: `[1 2]`},                                 // #02
+		{src: src0 + `s[1:3:4]`, res: `[1 2]`},                               // #03
+		{src: src0 + `s[:3:4]`, res: `[0 1 2]`},                              // #04
+		{src: src0 + `s[:2:]`, err: `final index required in 3-index slice`}, // #05
+		{src: src0 + `s[:3:4:]`, err: `expected ']', found ':'`},             // #06
+		{src: src0 + `s[2:]`, res: `[2 3]`},                                  // #07
+		{src: src0 + `s[:0]`, res: `[]`},                                     // #08
+		{src: `"Hello"[1:3]`, res: `el`},                                     // #09
+		{src: `s := "Hello"; s[1:3]`, res: `el`},                             // #10
+	})
+}
+
 func TestType(t *testing.T) {
 	src0 := `type (
 	I int