Merge pull request #21 from gobuffalo/handle-variadic-helpers

Handle variadic helpers
gobuffalo · Nov 14, 2017 · b038cde · b038cde
2 parents 7df6c66 + 5a8f698
commit b038cde
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Showing 2 changed files with 138 additions and 54 deletions.
diff --git a/compiler.go b/compiler.go
@@ -425,74 +425,132 @@ func (c *compiler) evalCallExpression(node *ast.CallExpression) (interface{}, er
 
 	rt := rv.Type()
 	rtNumIn := rt.NumIn()
+	isVariadic := rt.IsVariadic()
+	args := []reflect.Value{}
 
-	if len(node.Arguments) > rtNumIn {
-		return nil, errors.WithStack(errors.Errorf("%s too many arguments (%d for %d)", node.String(), len(node.Arguments), rtNumIn))
-	}
+	if !isVariadic {
+		if len(node.Arguments) > rtNumIn {
+			return nil, errors.WithStack(errors.Errorf("%s too many arguments (%d for %d)", node.String(), len(node.Arguments), rtNumIn))
+		}
 
-	args := []reflect.Value{}
-	for pos, a := range node.Arguments {
-		v, err := c.evalExpression(a)
-		if err != nil {
-			return nil, errors.WithStack(err)
+		for pos, a := range node.Arguments {
+			v, err := c.evalExpression(a)
+			if err != nil {
+				return nil, errors.WithStack(err)
+			}
+
+			var ar reflect.Value
+			expectedT := rt.In(pos)
+			if v != nil {
+				ar = reflect.ValueOf(v)
+			} else {
+				ar = reflect.New(expectedT).Elem()
+			}
+
+			actualT := ar.Type()
+			if !actualT.AssignableTo(expectedT) {
+				return nil, errors.WithStack(errors.Errorf("%+v (%T) is an invalid argument for %s at pos %d: expected (%s)", v, v, node.Function.String(), pos, expectedT))
+			}
+
+			args = append(args, ar)
 		}
 
-		var ar reflect.Value
-		expectedT := rt.In(pos)
-		if v != nil {
-			ar = reflect.ValueOf(v)
-		} else {
-			ar = reflect.New(expectedT).Elem()
+		hc := func(arg reflect.Type) {
+			if arg.Name() == helperContextKind {
+				hargs := HelperContext{
+					Context:  c.ctx,
+					compiler: c,
+					block:    node.Block,
+				}
+				args = append(args, reflect.ValueOf(hargs))
+				return
+			}
+			if arg.Name() == "Data" {
+				args = append(args, reflect.ValueOf(c.ctx.export()))
+				return
+			}
+			if arg.Kind() == reflect.Map {
+				args = append(args, reflect.ValueOf(map[string]interface{}{}))
+			}
 		}
 
-		actualT := ar.Type()
-		if !actualT.AssignableTo(expectedT) {
-			return nil, errors.WithStack(errors.Errorf("%+v (%T) is an invalid argument for %s at pos %d - evalCallExpression", v, v, node.Function.String(), pos))
+		if len(args) < rtNumIn {
+			// missing some args, let's see if we can figure out what they are.
+			diff := rtNumIn - len(args)
+			switch diff {
+			case 2:
+				// check last is help
+				// check if last -1 is map
+				arg := rt.In(rtNumIn - 2)
+				hc(arg)
+				last := rt.In(rtNumIn - 1)
+				hc(last)
+			case 1:
+				// check if help or map
+				last := rt.In(rtNumIn - 1)
+				hc(last)
+			}
 		}
 
-		args = append(args, ar)
-	}
+		if len(args) > rtNumIn {
+			return nil, errors.WithStack(errors.Errorf("%s too many arguments (%d for %d) - %+v", node.String(), len(args), rtNumIn, args))
+		}
+	} else {
+		// Variadic func
+		nodeArgs := node.Arguments
+		nodeArgsLen := len(nodeArgs)
+		if nodeArgsLen < rtNumIn {
+			return nil, errors.WithStack(errors.Errorf("%s too few arguments (%d for %d) - %+v", node.String(), len(args), rtNumIn, args))
+		}
+		var pos int
 
-	hc := func(arg reflect.Type) {
-		if arg.Name() == helperContextKind {
-			hargs := HelperContext{
-				Context:  c.ctx,
-				compiler: c,
-				block:    node.Block,
+		// Handle normal args
+		for pos = 0; pos < rtNumIn-1; pos++ {
+			v, err := c.evalExpression(nodeArgs[pos])
+			if err != nil {
+				return nil, errors.WithStack(err)
 			}
-			args = append(args, reflect.ValueOf(hargs))
-			return
-		}
-		if arg.Name() == "Data" {
-			args = append(args, reflect.ValueOf(c.ctx.export()))
-			return
+
+			var ar reflect.Value
+			expectedT := rt.In(pos)
+			if v != nil {
+				ar = reflect.ValueOf(v)
+			} else {
+				ar = reflect.New(expectedT).Elem()
+			}
+
+			actualT := ar.Type()
+			if !actualT.AssignableTo(expectedT) {
+				return nil, errors.WithStack(errors.Errorf("%+v (%T) is an invalid argument for %s at pos %d: expected (%s)", v, v, node.Function.String(), pos, expectedT))
+			}
+
+			args = append(args, ar)
 		}
-		if arg.Kind() == reflect.Map {
-			args = append(args, reflect.ValueOf(map[string]interface{}{}))
+
+		// Unroll variadic arg
+		expectedT := rt.In(pos).Elem()
+		for ; pos < nodeArgsLen; pos++ {
+			v, err := c.evalExpression(nodeArgs[pos])
+			if err != nil {
+				return nil, errors.WithStack(err)
+			}
+
+			var ar reflect.Value
+			if v != nil {
+				ar = reflect.ValueOf(v)
+			} else {
+				ar = reflect.New(expectedT)
+			}
+
+			actualT := ar.Type()
+			if !actualT.AssignableTo(expectedT) {
+				return nil, errors.WithStack(errors.Errorf("%+v (%T) is an invalid argument for %s at pos %d: expected (%s)", v, v, node.Function.String(), pos, expectedT))
+			}
+
+			args = append(args, ar)
 		}
 	}
 
-	if len(args) < rtNumIn {
-		// missing some args, let's see if we can figure out what they are.
-		diff := rtNumIn - len(args)
-		switch diff {
-		case 2:
-			// check last is help
-			// check if last -1 is map
-			arg := rt.In(rtNumIn - 2)
-			hc(arg)
-			last := rt.In(rtNumIn - 1)
-			hc(last)
-		case 1:
-			// check if help or map
-			last := rt.In(rtNumIn - 1)
-			hc(last)
-		}
-	}
-
-	if len(args) > rtNumIn {
-		return nil, errors.WithStack(errors.Errorf("%s too many arguments (%d for %d) - %+v", node.String(), len(args), rtNumIn, args))
-	}
 	if len(args) < rtNumIn {
 		return nil, errors.WithStack(errors.Errorf("%s too few arguments (%d for %d) - %+v", node.String(), len(args), rtNumIn, args))
 	}

diff --git a/plush_test.go b/plush_test.go
@@ -345,6 +345,32 @@ func Test_UndefinedArg(t *testing.T) {
 	r.Equal(ErrUnknownIdentifier, errors.Cause(err))
 }
 
+func Test_VariadicHelper(t *testing.T) {
+	r := require.New(t)
+	input := `<%= foo(1, 2, 3) %>`
+	ctx := NewContext()
+	ctx.Set("foo", func(args ...int) int {
+		return len(args)
+	})
+
+	s, err := Render(input, ctx)
+	r.NoError(err)
+	r.Equal("3", s)
+}
+
+func Test_VariadicHelperWithWrongParam(t *testing.T) {
+	r := require.New(t)
+	input := `<%= foo(1, 2, "test") %>`
+	ctx := NewContext()
+	ctx.Set("foo", func(args ...int) int {
+		return len(args)
+	})
+
+	_, err := Render(input, ctx)
+	r.Error(err)
+	r.Contains(err.Error(), "test (string) is an invalid argument for foo at pos 2: expected (int)")
+}
+
 func Test_RunScript(t *testing.T) {
 	r := require.New(t)
 	bb := &bytes.Buffer{}