Add AsKind and AsInt func

Author: antonmedv

checker/checker.go

@@ -31,7 +31,7 @@ func Check(tree *parser.Tree, config *conf.Config) (t reflect.Type, err error) {
 
 	if v.config.Expect != reflect.Invalid {
 		switch v.config.Expect {
-		case reflect.Int64, reflect.Float64:
+		case reflect.Int, reflect.Int64, reflect.Float64:
 			if !isNumber(t) {
 				return nil, fmt.Errorf("expected %v, but got %v", v.config.Expect, t)
 			}

compiler/compiler.go

@@ -37,10 +37,12 @@ func Compile(tree *parser.Tree, config *conf.Config) (program *Program, err erro
 	c.compile(tree.Node)
 
 	switch c.cast {
-	case reflect.Int64:
+	case reflect.Int:
 		c.emit(OpCast, 0)
-	case reflect.Float64:
+	case reflect.Int64:
 		c.emit(OpCast, 1)
+	case reflect.Float64:
+		c.emit(OpCast, 2)
 	}
 
 	program = &Program{

compiler/compiler_test.go

@@ -2,13 +2,9 @@ package compiler_test
 
 import (
 	"math"
-	"reflect"
 	"testing"
 
 	"github.com/antonmedv/expr"
-	"github.com/antonmedv/expr/compiler"
-	"github.com/antonmedv/expr/conf"
-	"github.com/antonmedv/expr/parser"
 	"github.com/antonmedv/expr/vm"
 	"github.com/antonmedv/expr/vm/runtime"
 	"github.com/stretchr/testify/assert"
@@ -242,25 +238,3 @@ func TestCompile(t *testing.T) {
 		assert.Equal(t, test.program.Disassemble(), program.Disassemble(), test.input)
 	}
 }
-
-func TestCompile_cast(t *testing.T) {
-	input := `1`
-	expected := &vm.Program{
-		Constants: []interface{}{
-			1,
-		},
-		Bytecode: []vm.Opcode{
-			vm.OpPush,
-			vm.OpCast,
-		},
-		Arguments: []int{0, 1},
-	}
-
-	tree, err := parser.Parse(input)
-	require.NoError(t, err)
-
-	program, err := compiler.Compile(tree, &conf.Config{Expect: reflect.Float64})
-	require.NoError(t, err)
-
-	assert.Equal(t, expected.Disassemble(), program.Disassemble())
-}

expr.go

@@ -75,21 +75,35 @@ func ConstExpr(fn string) Option {
 	}
 }
 
-// AsBool tells the compiler to expect boolean result.
+// AsKind tells the compiler to expect kind of the result.
+func AsKind(kind reflect.Kind) Option {
+	return func(c *conf.Config) {
+		c.Expect = kind
+	}
+}
+
+// AsBool tells the compiler to expect a boolean result.
 func AsBool() Option {
 	return func(c *conf.Config) {
 		c.Expect = reflect.Bool
 	}
 }
 
-// AsInt64 tells the compiler to expect int64 result.
+// AsInt tells the compiler to expect an int result.
+func AsInt() Option {
+	return func(c *conf.Config) {
+		c.Expect = reflect.Int
+	}
+}
+
+// AsInt64 tells the compiler to expect an int64 result.
 func AsInt64() Option {
 	return func(c *conf.Config) {
 		c.Expect = reflect.Int64
 	}
 }
 
-// AsFloat64 tells the compiler to expect float64 result.
+// AsFloat64 tells the compiler to expect a float64 result.
 func AsFloat64() Option {
 	return func(c *conf.Config) {
 		c.Expect = reflect.Float64

expr_test.go

@@ -135,6 +135,24 @@ func ExampleEnv_tagged_field_names() {
 	// Output : Hello World
 }
 
+func ExampleAsKind() {
+	program, err := expr.Compile("{a: 1, b: 2}", expr.AsKind(reflect.Map))
+	if err != nil {
+		fmt.Printf("%v", err)
+		return
+	}
+
+	output, err := expr.Run(program, nil)
+	if err != nil {
+		fmt.Printf("%v", err)
+		return
+	}
+
+	fmt.Printf("%v", output)
+
+	// Output: map[a:1 b:2]
+}
+
 func ExampleAsBool() {
 	env := map[string]int{
 		"foo": 0,
@@ -169,8 +187,8 @@ func ExampleAsBool_error() {
 	// Output: expected bool, but got int
 }
 
-func ExampleAsFloat64() {
-	program, err := expr.Compile("42", expr.AsFloat64())
+func ExampleAsInt() {
+	program, err := expr.Compile("42", expr.AsInt())
 	if err != nil {
 		fmt.Printf("%v", err)
 		return
@@ -182,17 +200,9 @@ func ExampleAsFloat64() {
 		return
 	}
 
-	fmt.Printf("%v", output.(float64))
-
-	// Output: 42
-}
+	fmt.Printf("%T(%v)", output, output)
 
-func ExampleAsFloat64_error() {
-	_, err := expr.Compile(`!!true`, expr.AsFloat64())
-
-	fmt.Printf("%v", err)
-
-	// Output: expected float64, but got bool
+	// Output: int(42)
 }
 
 func ExampleAsInt64() {
@@ -217,6 +227,32 @@ func ExampleAsInt64() {
 	// Output: 5
 }
 
+func ExampleAsFloat64() {
+	program, err := expr.Compile("42", expr.AsFloat64())
+	if err != nil {
+		fmt.Printf("%v", err)
+		return
+	}
+
+	output, err := expr.Run(program, nil)
+	if err != nil {
+		fmt.Printf("%v", err)
+		return
+	}
+
+	fmt.Printf("%v", output.(float64))
+
+	// Output: 42
+}
+
+func ExampleAsFloat64_error() {
+	_, err := expr.Compile(`!!true`, expr.AsFloat64())
+
+	fmt.Printf("%v", err)
+
+	// Output: expected float64, but got bool
+}
+
 func ExampleOperator() {
 	code := `
 		Now() > CreatedAt &&

vm/vm.go

@@ -354,8 +354,10 @@ func (vm *VM) Run(program *Program, env interface{}) (out interface{}, err error
 			t := arg
 			switch t {
 			case 0:
-				vm.push(runtime.ToInt64(vm.pop()))
+				vm.push(runtime.ToInt(vm.pop()))
 			case 1:
+				vm.push(runtime.ToInt64(vm.pop()))
+			case 2:
 				vm.push(runtime.ToFloat64(vm.pop()))
 			}