diff --git a/ucl/ast.go b/ucl/ast.go
index 54aaa64..719f381 100644
--- a/ucl/ast.go
+++ b/ucl/ast.go
@@ -98,6 +98,7 @@ type astDotSuffix struct {
 }
 
 type astDot struct {
+	Pos       lexer.Position
 	Arg       astCmdArg      `parser:"@@"`
 	DotSuffix []astDotSuffix `parser:"( DOT @@ )*"`
 }
diff --git a/ucl/builtins.go b/ucl/builtins.go
index cc946b3..0c84824 100644
--- a/ucl/builtins.go
+++ b/ucl/builtins.go
@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+
+	"github.com/alecthomas/participle/v2/lexer"
 )
 
 func echoBuiltin(ctx context.Context, args invocationArgs) (Object, error) {
@@ -509,7 +511,10 @@ func lenBuiltin(ctx context.Context, args invocationArgs) (Object, error) {
 	return IntObject(0), nil
 }
 
-func indexLookup(ctx context.Context, obj, elem Object) (Object, error) {
+func indexLookup(ctx context.Context, obj, elem Object, pos lexer.Position) (Object, error) {
+	if obj == nil {
+		return nil, nil
+	}
 	switch v := obj.(type) {
 	case Listable:
 		intIdx, ok := elem.(IntObject)
@@ -525,9 +530,11 @@ func indexLookup(ctx context.Context, obj, elem Object) (Object, error) {
 	case Hashable:
 		strIdx, ok := elem.(StringObject)
 		if !ok {
-			return nil, errors.New("expected string for Hashable")
+			return nil, nil
 		}
 		return v.Value(string(strIdx)), nil
+	default:
+		return nil, notIndexableError(pos)
 	}
 	return nil, nil
 }
@@ -539,7 +546,7 @@ func indexBuiltin(ctx context.Context, args invocationArgs) (Object, error) {
 
 	val := args.args[0]
 	for _, idx := range args.args[1:] {
-		newVal, err := indexLookup(ctx, val, idx)
+		newVal, err := indexLookup(ctx, val, idx, lexer.Position{})
 		if err != nil {
 			return nil, err
 		}
diff --git a/ucl/builtins_test.go b/ucl/builtins_test.go
index 9361ae4..effb183 100644
--- a/ucl/builtins_test.go
+++ b/ucl/builtins_test.go
@@ -5,9 +5,10 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"github.com/stretchr/testify/assert"
 	"strings"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 type testIterator struct {
@@ -57,6 +58,19 @@ func WithTestBuiltin() InstOption {
 			return &a, nil
 		}))
 
+		i.rootEC.addCmd("rearrange", invokableFunc(func(ctx context.Context, args invocationArgs) (Object, error) {
+			var as ListObject = make([]Object, 0)
+
+			for _, a := range args.args {
+				vs, ok := args.kwargs[a.String()]
+				if ok {
+					as = append(as, vs.Index(0))
+				}
+			}
+
+			return &as, nil
+		}))
+
 		i.rootEC.addCmd("error", invokableFunc(func(ctx context.Context, args invocationArgs) (Object, error) {
 			if len(args.args) == 0 {
 				return nil, errors.New("an error occurred")
@@ -131,10 +145,10 @@ func TestBuiltins_Echo(t *testing.T) {
 			echo "world"	# command after this
 ;
 		`, want: "Hello\nworld\n"},
-		{desc: "interpolated string 1", expr: `$what = "world" ; echo "Hello, $what"`, want: "Hello, world\n"},
-		{desc: "interpolated string 2", expr: `$what = "world" ; echo "Hello, \$what"`, want: "Hello, $what\n"},
+		{desc: "interpolated string 1", expr: `what = "world" ; echo "Hello, $what"`, want: "Hello, world\n"},
+		{desc: "interpolated string 2", expr: `what = "world" ; echo "Hello, \$what"`, want: "Hello, $what\n"},
 		{desc: "interpolated string 3", expr: `echo "separate\nlines\n\tand tabs"`, want: "separate\nlines\n\tand tabs\n"},
-		{desc: "interpolated string 4", expr: `$what = "Hello" ; $where = "world" ; echo "$what, $where"`, want: "Hello, world\n"},
+		{desc: "interpolated string 4", expr: `what = "Hello" ; where = "world" ; echo "$what, $where"`, want: "Hello, world\n"},
 		{desc: "interpolated string 5", expr: `
 			for [123 "foo" true ()] { |x|
                 echo "[[$x]]"
@@ -167,19 +181,19 @@ func TestBuiltins_If(t *testing.T) {
 		want string
 	}{
 		{desc: "single then", expr: `
-			$x = "Hello"
+			x = "Hello"
 			if $x {
 				echo "true"
 			}`, want: "true\n(nil)\n"},
 		{desc: "single then and else", expr: `
-			$x = "Hello"
+			x = "Hello"
 			if $x {
 				echo "true"
 			} else {
 				echo "false"
 			}`, want: "true\n(nil)\n"},
 		{desc: "single then, elif and else", expr: `
-			$x = "Hello"
+			x = "Hello"
 			if $y {
 				echo "y is true"
 			} elif $x {
@@ -188,14 +202,14 @@ func TestBuiltins_If(t *testing.T) {
 				echo "nothings x"
 			}`, want: "x is true\n(nil)\n"},
 		{desc: "single then and elif, no else", expr: `
-			$x = "Hello"
+			x = "Hello"
 			if $y {
 				echo "y is true"
 			} elif $x {
 				echo "x is true"
 			}`, want: "x is true\n(nil)\n"},
 		{desc: "single then, two elif, and else", expr: `
-			$x = "Hello"
+			x = "Hello"
 			if $z {
 				echo "z is true"
 			} elif $y {
@@ -213,15 +227,15 @@ func TestBuiltins_If(t *testing.T) {
 			} else {
 				echo "none is true"
 			}`, want: "none is true\n(nil)\n"},
-		{desc: "compressed then", expr: `$x = "Hello" ; if $x { echo "true" }`, want: "true\n(nil)\n"},
+		{desc: "compressed then", expr: `x = "Hello" ; if $x { echo "true" }`, want: "true\n(nil)\n"},
 		{desc: "compressed else", expr: `if $x { echo "true" } else { echo "false" }`, want: "false\n(nil)\n"},
 		{desc: "compressed if", expr: `if $x { echo "x" } elif $y { echo "y" } else { echo "false" }`, want: "false\n(nil)\n"},
-		{desc: "if of itr 1", expr: `$i = itr ; if $i { echo "more" } else { echo "none" }`, want: "more\n(nil)\n"},
-		{desc: "if of itr 2", expr: `$i = itr ; for (seq 1) { head $i } ; if $i { echo "more" } else { echo "none" }`, want: "more\n(nil)\n"},
-		{desc: "if of itr 3", expr: `$i = itr ; for (seq 3) { head $i } ; if $i { echo "more" } else { echo "none" }`, want: "none\n(nil)\n"},
-		{desc: "if of itr 4", expr: `$i = (itr | map { |x| add 2 $x }) ; if $i { echo "more" } else { echo "none" }`, want: "more\n(nil)\n"},
-		{desc: "if of itr 5", expr: `$i = (itr | filter { |x| () }) ; if $i { echo "more" } else { echo "none" }`, want: "none\n(nil)\n"},
-		{desc: "if of itr 6", expr: `$i = (itr | filter { |x| 1 }) ; if $i { echo "more" } else { echo "none" }`, want: "more\n(nil)\n"},
+		{desc: "if of itr 1", expr: `i = itr ; if $i { echo "more" } else { echo "none" }`, want: "more\n(nil)\n"},
+		{desc: "if of itr 2", expr: `i = itr ; for (seq 1) { head $i } ; if $i { echo "more" } else { echo "none" }`, want: "more\n(nil)\n"},
+		{desc: "if of itr 3", expr: `i = itr ; for (seq 3) { head $i } ; if $i { echo "more" } else { echo "none" }`, want: "none\n(nil)\n"},
+		{desc: "if of itr 4", expr: `i = (itr | map { |x| add 2 $x }) ; if $i { echo "more" } else { echo "none" }`, want: "more\n(nil)\n"},
+		{desc: "if of itr 5", expr: `i = (itr | filter { |x| () }) ; if $i { echo "more" } else { echo "none" }`, want: "none\n(nil)\n"},
+		{desc: "if of itr 6", expr: `i = (itr | filter { |x| 1 }) ; if $i { echo "more" } else { echo "none" }`, want: "more\n(nil)\n"},
 	}
 
 	for _, tt := range tests {
@@ -508,6 +522,9 @@ func TestBuiltins_Procs(t *testing.T) {
 			echo (call $er ["xxx"])
 			echo (call $er ["yyy"])
 			`, want: "Xxxx\nXxxxyyy\n(nil)\n"},
+		{desc: "calling with kwargs", expr: `
+			echo (call rearrange [b a] [a:"ey" b:"bee"])
+			`, want: "[bee ey]\n(nil)\n"},
 	}
 
 	for _, tt := range tests {
diff --git a/ucl/errors.go b/ucl/errors.go
index a948b03..f7f80e9 100644
--- a/ucl/errors.go
+++ b/ucl/errors.go
@@ -3,6 +3,7 @@ package ucl
 import (
 	"errors"
 	"fmt"
+
 	"github.com/alecthomas/participle/v2/lexer"
 )
 
@@ -12,6 +13,7 @@ var (
 
 var (
 	tooManyFinallyBlocksError = newBadUsage("try needs at most 1 finally")
+	notIndexableError         = newBadUsage("index only support on lists and hashes")
 )
 
 type errorWithPos struct {
diff --git a/ucl/eval.go b/ucl/eval.go
index b2edca2..82313df 100644
--- a/ucl/eval.go
+++ b/ucl/eval.go
@@ -5,6 +5,8 @@ import (
 	"errors"
 	"fmt"
 	"strings"
+
+	"github.com/alecthomas/participle/v2/lexer"
 )
 
 type evaluator struct {
@@ -205,7 +207,7 @@ func (e evaluator) evalDot(ctx context.Context, ec *evalCtx, n astDot) (Object,
 			}
 		}
 
-		res, err = indexLookup(ctx, res, idx)
+		res, err = indexLookup(ctx, res, idx, n.Pos)
 		if err != nil {
 			return nil, err
 		}
@@ -258,9 +260,11 @@ func (e evaluator) evalArg(ctx context.Context, ec *evalCtx, n astCmdArg) (Objec
 
 func (e evaluator) assignArg(ctx context.Context, ec *evalCtx, n astCmdArg, toVal Object) (Object, error) {
 	switch {
+	case n.Ident != nil:
+		ec.setOrDefineVar(n.Ident.String(), toVal)
+		return toVal, nil
 	case n.Literal != nil:
-		// We may use this for variable setting?
-		return nil, errors.New("cannot assign to a literal")
+		return nil, errors.New("cannot assign to a literal value")
 	case n.Var != nil:
 		ec.setOrDefineVar(*n.Var, toVal)
 		return toVal, nil
@@ -428,7 +432,7 @@ func (e evaluator) interpolateLongIdent(ctx context.Context, ec *evalCtx, n *ast
 			}
 		}
 
-		res, err = indexLookup(ctx, res, idx)
+		res, err = indexLookup(ctx, res, idx, lexer.Position{})
 		if err != nil {
 			return "", err
 		}
diff --git a/ucl/inst_test.go b/ucl/inst_test.go
index e2dbf60..718d0b7 100644
--- a/ucl/inst_test.go
+++ b/ucl/inst_test.go
@@ -4,19 +4,22 @@ import (
 	"bytes"
 	"context"
 	"strings"
+
 	"ucl.lmika.dev/ucl"
 
-	"github.com/stretchr/testify/assert"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestInst_Eval(t *testing.T) {
 	tests := []struct {
-		desc    string
-		expr    string
-		want    any
-		wantObj bool
-		wantErr error
+		desc      string
+		expr      string
+		want      any
+		wantObj   bool
+		wantAnErr bool
+		wantErr   error
 	}{
 		{desc: "simple string", expr: `firstarg "hello"`, want: "hello"},
 		{desc: "simple int 1", expr: `firstarg 123`, want: 123},
@@ -100,7 +103,14 @@ func TestInst_Eval(t *testing.T) {
 		{desc: "dot idents 6", expr: `$x = [alpha:"hello" bravo:"world"] ; $x.("charlie")`, want: nil},
 		{desc: "dot idents 7", expr: `$x = [MORE:"stuff"] ; $x.("more" | toUpper)`, want: "stuff"},
 		{desc: "dot idents 8", expr: `$x = [MORE:"stuff"] ; $x.(toUpper ("more"))`, want: "stuff"},
-		{desc: "dot idents 9", expr: `$x = [MORE:"stuff"] ; x.y`, want: nil},
+		{desc: "dot idents 9", expr: `$x = [MORE:"stuff"] ; $x.y`, want: nil},
+
+		{desc: "dot err 1", expr: `$x = [1 2 3] ; $x.Hello`, want: nil},
+		{desc: "dot err 2", expr: `$x = [1 2 3] ; $x.("world")`, want: nil},
+		{desc: "dot err 4", expr: `$x = [a:1 b:2] ; $x.(5)`, want: nil},
+		{desc: "dot err 3", expr: `$x = [a:1 b:2] ; $x.(0)`, want: nil},
+		{desc: "dot err 5", expr: `$x = 123 ; $x.(5)`, wantAnErr: true},
+		{desc: "dot err 6", expr: `$x = 123 ; $x.Five`, wantAnErr: true},
 
 		{desc: "parse comments 1", expr: parseComments1, wantObj: true, wantErr: nil},
 		{desc: "parse comments 2", expr: parseComments2, wantObj: true, wantErr: nil},
@@ -118,6 +128,8 @@ func TestInst_Eval(t *testing.T) {
 
 			if tt.wantErr != nil {
 				assert.ErrorIs(t, err, tt.wantErr)
+			} else if tt.wantAnErr {
+				assert.Error(t, err)
 			} else if tt.wantObj {
 				assert.NoError(t, err)
 				_, isObj := res.(ucl.Object)