diff --git a/pkg/compiler/codegen.go b/pkg/compiler/codegen.go index 42970458b..06dacd81b 100644 --- a/pkg/compiler/codegen.go +++ b/pkg/compiler/codegen.go @@ -269,15 +269,23 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor { ast.Walk(c, n.Rhs[i]) name := t.X.(*ast.Ident).Name c.emitLoadLocal(name) - // For now storm only supports basic index operations. Hence we - // cast this to an *ast.BasicLit (1, 2 , 3) - indexStr := t.Index.(*ast.BasicLit).Value - index, err := strconv.Atoi(indexStr) - if err != nil { - c.prog.Err = fmt.Errorf("failed to convert slice index to integer") + switch ind := t.Index.(type) { + case *ast.BasicLit: + indexStr := ind.Value + index, err := strconv.Atoi(indexStr) + if err != nil { + c.prog.Err = fmt.Errorf("failed to convert slice index to integer") + return nil + } + c.emitStoreStructField(index) + case *ast.Ident: + c.emitLoadLocal(ind.Name) + emitOpcode(c.prog.BinWriter, opcode.ROT) + emitOpcode(c.prog.BinWriter, opcode.SETITEM) + default: + c.prog.Err = fmt.Errorf("unsupported index expression") return nil } - c.emitStoreStructField(index) } } return nil diff --git a/pkg/vm/tests/slice_test.go b/pkg/vm/tests/slice_test.go new file mode 100644 index 000000000..8d0d67f9d --- /dev/null +++ b/pkg/vm/tests/slice_test.go @@ -0,0 +1,53 @@ +package vm_test + +import ( + "math/big" + "testing" +) + +var sliceTestCases = []testCase{ + { + "constant index", + ` + package foo + func Main() int { + a := []int{0,0} + a[1] = 42 + return a[1]+0 + } + `, + big.NewInt(42), + }, + { + "variable index", + ` + package foo + func Main() int { + a := []int{0,0} + i := 1 + a[i] = 42 + return a[1]+0 + } + `, + big.NewInt(42), + }, + { + "complex test", + ` + package foo + func Main() int { + a := []int{1,2,3} + x := a[0] + a[x] = a[x] + 4 + a[x] = a[x] + a[2] + return a[1] + } + `, + big.NewInt(9), + }, +} + +func TestSliceOperations(t *testing.T) { + runTestCases(t, sliceTestCases) +} +