diff --git a/expressions/evaluator_test.go b/expressions/evaluator_test.go
index de709ac..fbdf9c8 100644
--- a/expressions/evaluator_test.go
+++ b/expressions/evaluator_test.go
@@ -7,26 +7,17 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-var evaluatorTestContext = Context{map[string]interface{}{
-	"n":  123,
-	"ar": []string{"first", "second", "third"},
-	"obj": map[string]interface{}{
-		"a": "first",
-		"b": map[string]interface{}{"c": "d"},
-		"c": []string{"r", "g", "b"},
-	},
-},
-}
-
 var evaluatorTests = []struct {
 	in       string
 	expected interface{}
 }{
-	// Constants
+	// Literals
 	{"12", 12},
 	{"12.3", 12.3},
 	{"true", true},
 	{"false", false},
+	{`'abc'`, "abc"},
+	{`"abc"`, "abc"},
 
 	// Variables
 	{"n", 123},
@@ -57,6 +48,17 @@ var evaluatorTests = []struct {
 	{"1.0 < 2", true},
 }
 
+var evaluatorTestContext = Context{map[string]interface{}{
+	"n":  123,
+	"ar": []string{"first", "second", "third"},
+	"obj": map[string]interface{}{
+		"a": "first",
+		"b": map[string]interface{}{"c": "d"},
+		"c": []string{"r", "g", "b"},
+	},
+},
+}
+
 func TestEvaluator(t *testing.T) {
 	for i, test := range evaluatorTests {
 		t.Run(fmt.Sprint(i), func(t *testing.T) {
diff --git a/expressions/scanner.go b/expressions/scanner.go
index 649b2b3..fb2ac92 100644
--- a/expressions/scanner.go
+++ b/expressions/scanner.go
@@ -1,162 +1,170 @@
-//line scanner.rl:1
 
+//line scanner.rl:1
 // Adapted from https://github.com/mhamrah/thermostat
 package expressions
 
 import "fmt"
 import "strconv"
 
+
 //line scanner.go:11
 var _expression_actions []byte = []byte{
-	0, 1, 0, 1, 1, 1, 2, 1, 9,
-	1, 10, 1, 11, 1, 12, 1, 13,
-	1, 14, 1, 15, 1, 16, 1, 17,
-	1, 18, 2, 2, 3, 2, 2, 4,
-	2, 2, 5, 2, 2, 6, 2, 2,
-	7, 2, 2, 8,
+	0, 1, 0, 1, 1, 1, 2, 1, 9, 
+	1, 10, 1, 11, 1, 12, 1, 13, 
+	1, 14, 1, 15, 1, 16, 1, 17, 
+	1, 18, 1, 19, 2, 2, 3, 2, 
+	2, 4, 2, 2, 5, 2, 2, 6, 
+	2, 2, 7, 2, 2, 8, 
 }
 
 var _expression_key_offsets []byte = []byte{
-	0, 2, 26, 29, 30, 33, 35, 38,
-	39, 46, 54, 62, 70, 78, 86, 94,
-	102, 110, 118, 126, 134, 142, 150, 158,
-	166,
+	0, 1, 2, 4, 30, 33, 34, 35, 
+	36, 39, 41, 44, 45, 52, 60, 68, 
+	76, 84, 92, 100, 108, 116, 124, 132, 
+	140, 148, 156, 164, 172, 
 }
 
 var _expression_trans_keys []byte = []byte{
-	48, 57, 32, 33, 45, 46, 59, 61,
-	91, 93, 95, 97, 99, 102, 111, 116,
-	9, 13, 48, 57, 60, 62, 65, 90,
-	98, 122, 32, 9, 13, 61, 46, 48,
-	57, 48, 57, 46, 48, 57, 61, 95,
-	48, 57, 65, 90, 97, 122, 95, 110,
-	48, 57, 65, 90, 97, 122, 95, 100,
-	48, 57, 65, 90, 97, 122, 95, 111,
-	48, 57, 65, 90, 97, 122, 95, 110,
-	48, 57, 65, 90, 97, 122, 95, 116,
-	48, 57, 65, 90, 97, 122, 95, 97,
-	48, 57, 65, 90, 98, 122, 95, 105,
-	48, 57, 65, 90, 97, 122, 95, 110,
-	48, 57, 65, 90, 97, 122, 95, 115,
-	48, 57, 65, 90, 97, 122, 95, 97,
-	48, 57, 65, 90, 98, 122, 95, 108,
-	48, 57, 65, 90, 97, 122, 95, 115,
-	48, 57, 65, 90, 97, 122, 95, 101,
-	48, 57, 65, 90, 97, 122, 95, 114,
-	48, 57, 65, 90, 97, 122, 95, 114,
-	48, 57, 65, 90, 97, 122, 95, 117,
-	48, 57, 65, 90, 97, 122,
+	34, 39, 48, 57, 32, 33, 34, 39, 
+	45, 46, 59, 61, 91, 93, 95, 97, 
+	99, 102, 111, 116, 9, 13, 48, 57, 
+	60, 62, 65, 90, 98, 122, 32, 9, 
+	13, 61, 34, 39, 46, 48, 57, 48, 
+	57, 46, 48, 57, 61, 95, 48, 57, 
+	65, 90, 97, 122, 95, 110, 48, 57, 
+	65, 90, 97, 122, 95, 100, 48, 57, 
+	65, 90, 97, 122, 95, 111, 48, 57, 
+	65, 90, 97, 122, 95, 110, 48, 57, 
+	65, 90, 97, 122, 95, 116, 48, 57, 
+	65, 90, 97, 122, 95, 97, 48, 57, 
+	65, 90, 98, 122, 95, 105, 48, 57, 
+	65, 90, 97, 122, 95, 110, 48, 57, 
+	65, 90, 97, 122, 95, 115, 48, 57, 
+	65, 90, 97, 122, 95, 97, 48, 57, 
+	65, 90, 98, 122, 95, 108, 48, 57, 
+	65, 90, 97, 122, 95, 115, 48, 57, 
+	65, 90, 97, 122, 95, 101, 48, 57, 
+	65, 90, 97, 122, 95, 114, 48, 57, 
+	65, 90, 97, 122, 95, 114, 48, 57, 
+	65, 90, 97, 122, 95, 117, 48, 57, 
+	65, 90, 97, 122, 
 }
 
 var _expression_single_lengths []byte = []byte{
-	0, 14, 1, 1, 1, 0, 1, 1,
-	1, 2, 2, 2, 2, 2, 2, 2,
-	2, 2, 2, 2, 2, 2, 2, 2,
-	2,
+	1, 1, 0, 16, 1, 1, 1, 1, 
+	1, 0, 1, 1, 1, 2, 2, 2, 
+	2, 2, 2, 2, 2, 2, 2, 2, 
+	2, 2, 2, 2, 2, 
 }
 
 var _expression_range_lengths []byte = []byte{
-	1, 5, 1, 0, 1, 1, 1, 0,
-	3, 3, 3, 3, 3, 3, 3, 3,
-	3, 3, 3, 3, 3, 3, 3, 3,
-	3,
+	0, 0, 1, 5, 1, 0, 0, 0, 
+	1, 1, 1, 0, 3, 3, 3, 3, 
+	3, 3, 3, 3, 3, 3, 3, 3, 
+	3, 3, 3, 3, 3, 
 }
 
 var _expression_index_offsets []byte = []byte{
-	0, 2, 22, 25, 27, 30, 32, 35,
-	37, 42, 48, 54, 60, 66, 72, 78,
-	84, 90, 96, 102, 108, 114, 120, 126,
-	132,
+	0, 2, 4, 6, 28, 31, 33, 35, 
+	37, 40, 42, 45, 47, 52, 58, 64, 
+	70, 76, 82, 88, 94, 100, 106, 112, 
+	118, 124, 130, 136, 142, 
 }
 
 var _expression_indicies []byte = []byte{
-	1, 0, 3, 4, 5, 6, 8, 10,
-	8, 8, 11, 12, 13, 14, 15, 16,
-	3, 7, 9, 11, 11, 2, 3, 3,
-	17, 19, 18, 21, 7, 20, 1, 18,
-	1, 7, 22, 23, 20, 11, 11, 11,
-	11, 18, 11, 25, 11, 11, 11, 24,
-	11, 26, 11, 11, 11, 24, 11, 27,
-	11, 11, 11, 24, 11, 28, 11, 11,
-	11, 24, 11, 29, 11, 11, 11, 24,
-	11, 30, 11, 11, 11, 24, 11, 31,
-	11, 11, 11, 24, 11, 32, 11, 11,
-	11, 24, 11, 26, 11, 11, 11, 24,
-	11, 33, 11, 11, 11, 24, 11, 34,
-	11, 11, 11, 24, 11, 35, 11, 11,
-	11, 24, 11, 36, 11, 11, 11, 24,
-	11, 26, 11, 11, 11, 24, 11, 37,
-	11, 11, 11, 24, 11, 35, 11, 11,
-	11, 24,
+	2, 1, 2, 3, 4, 0, 6, 7, 
+	8, 9, 10, 11, 13, 15, 13, 13, 
+	16, 17, 18, 19, 20, 21, 6, 12, 
+	14, 16, 16, 5, 6, 6, 22, 24, 
+	23, 2, 1, 2, 3, 26, 12, 25, 
+	4, 23, 4, 12, 27, 28, 25, 16, 
+	16, 16, 16, 23, 16, 30, 16, 16, 
+	16, 29, 16, 31, 16, 16, 16, 29, 
+	16, 32, 16, 16, 16, 29, 16, 33, 
+	16, 16, 16, 29, 16, 34, 16, 16, 
+	16, 29, 16, 35, 16, 16, 16, 29, 
+	16, 36, 16, 16, 16, 29, 16, 37, 
+	16, 16, 16, 29, 16, 31, 16, 16, 
+	16, 29, 16, 38, 16, 16, 16, 29, 
+	16, 39, 16, 16, 16, 29, 16, 40, 
+	16, 16, 16, 29, 16, 41, 16, 16, 
+	16, 29, 16, 31, 16, 16, 16, 29, 
+	16, 42, 16, 16, 16, 29, 16, 40, 
+	16, 16, 16, 29, 
 }
 
 var _expression_trans_targs []byte = []byte{
-	1, 5, 1, 2, 3, 4, 5, 6,
-	1, 3, 7, 8, 9, 11, 18, 22,
-	23, 1, 1, 1, 1, 0, 1, 1,
-	1, 10, 8, 12, 13, 14, 15, 16,
-	17, 19, 20, 21, 8, 24,
+	3, 0, 3, 1, 9, 3, 4, 5, 
+	6, 7, 8, 9, 10, 3, 5, 11, 
+	12, 13, 15, 22, 26, 27, 3, 3, 
+	3, 3, 2, 3, 3, 3, 14, 12, 
+	16, 17, 18, 19, 20, 21, 23, 24, 
+	25, 12, 28, 
 }
 
 var _expression_trans_actions []byte = []byte{
-	23, 27, 13, 0, 42, 5, 30, 0,
-	7, 30, 0, 39, 0, 0, 0, 0,
-	0, 19, 25, 11, 21, 0, 15, 9,
-	17, 0, 36, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 33, 0,
+	25, 0, 7, 0, 29, 15, 0, 44, 
+	5, 5, 5, 35, 0, 9, 35, 0, 
+	41, 0, 0, 0, 0, 0, 21, 27, 
+	13, 23, 0, 17, 11, 19, 0, 38, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 32, 0, 
 }
 
 var _expression_to_state_actions []byte = []byte{
-	0, 1, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0,
+	0, 0, 0, 1, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 
 }
 
 var _expression_from_state_actions []byte = []byte{
-	0, 3, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0,
+	0, 0, 0, 3, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 
 }
 
 var _expression_eof_trans []byte = []byte{
-	1, 0, 18, 19, 21, 19, 23, 21,
-	19, 25, 25, 25, 25, 25, 25, 25,
-	25, 25, 25, 25, 25, 25, 25, 25,
-	25,
+	1, 1, 1, 0, 23, 24, 26, 26, 
+	26, 24, 28, 26, 24, 30, 30, 30, 
+	30, 30, 30, 30, 30, 30, 30, 30, 
+	30, 30, 30, 30, 30, 
 }
 
-const expression_start int = 1
-const expression_first_final int = 1
+const expression_start int = 3
+const expression_first_final int = 3
 const expression_error int = -1
 
-const expression_en_main int = 1
+const expression_en_main int = 3
+
 
 //line scanner.rl:13
+
+
 type lexer struct {
-	data        []byte
-	p, pe, cs   int
-	ts, te, act int
-	val         func(Context) interface{}
+    data []byte
+    p, pe, cs int
+    ts, te, act int
+		val func(Context) interface{}
 }
 
-func (l *lexer) token() string {
+func (l* lexer) token() string {
 	return string(l.data[l.ts:l.te])
 }
 
 func newLexer(data []byte) *lexer {
 	lex := &lexer{
-		data: data,
-		pe:   len(data),
+			data: data,
+			pe: len(data),
 	}
-
-//line scanner.go:159
+	
+//line scanner.go:163
 	{
-		lex.cs = expression_start
-		lex.ts = 0
-		lex.te = 0
-		lex.act = 0
+	 lex.cs = expression_start
+	 lex.ts = 0
+	 lex.te = 0
+	 lex.act = 0
 	}
 
 //line scanner.rl:32
@@ -167,304 +175,273 @@ func (lex *lexer) Lex(out *yySymType) int {
 	eof := lex.pe
 	tok := 0
 
-//line scanner.go:176
+	
+//line scanner.go:180
 	{
-		var _klen int
-		var _trans int
-		var _acts int
-		var _nacts uint
-		var _keys int
-		if (lex.p) == (lex.pe) {
-			goto _test_eof
-		}
-	_resume:
-		_acts = int(_expression_from_state_actions[lex.cs])
-		_nacts = uint(_expression_actions[_acts])
-		_acts++
-		for ; _nacts > 0; _nacts-- {
-			_acts++
-			switch _expression_actions[_acts-1] {
-			case 1:
+	var _klen int
+	var _trans int
+	var _acts int
+	var _nacts uint
+	var _keys int
+	if ( lex.p) == ( lex.pe) {
+		goto _test_eof
+	}
+_resume:
+	_acts = int(_expression_from_state_actions[ lex.cs])
+	_nacts = uint(_expression_actions[_acts]); _acts++
+	for ; _nacts > 0; _nacts-- {
+		 _acts++
+		switch _expression_actions[_acts - 1] {
+		case 1:
 //line NONE:1
-				lex.ts = (lex.p)
+ lex.ts = ( lex.p)
 
-//line scanner.go:196
-			}
-		}
-
-		_keys = int(_expression_key_offsets[lex.cs])
-		_trans = int(_expression_index_offsets[lex.cs])
-
-		_klen = int(_expression_single_lengths[lex.cs])
-		if _klen > 0 {
-			_lower := int(_keys)
-			var _mid int
-			_upper := int(_keys + _klen - 1)
-			for {
-				if _upper < _lower {
-					break
-				}
-
-				_mid = _lower + ((_upper - _lower) >> 1)
-				switch {
-				case lex.data[(lex.p)] < _expression_trans_keys[_mid]:
-					_upper = _mid - 1
-				case lex.data[(lex.p)] > _expression_trans_keys[_mid]:
-					_lower = _mid + 1
-				default:
-					_trans += int(_mid - int(_keys))
-					goto _match
-				}
-			}
-			_keys += _klen
-			_trans += _klen
-		}
-
-		_klen = int(_expression_range_lengths[lex.cs])
-		if _klen > 0 {
-			_lower := int(_keys)
-			var _mid int
-			_upper := int(_keys + (_klen << 1) - 2)
-			for {
-				if _upper < _lower {
-					break
-				}
-
-				_mid = _lower + (((_upper - _lower) >> 1) & ^1)
-				switch {
-				case lex.data[(lex.p)] < _expression_trans_keys[_mid]:
-					_upper = _mid - 2
-				case lex.data[(lex.p)] > _expression_trans_keys[_mid+1]:
-					_lower = _mid + 2
-				default:
-					_trans += int((_mid - int(_keys)) >> 1)
-					goto _match
-				}
-			}
-			_trans += _klen
-		}
-
-	_match:
-		_trans = int(_expression_indicies[_trans])
-	_eof_trans:
-		lex.cs = int(_expression_trans_targs[_trans])
-
-		if _expression_trans_actions[_trans] == 0 {
-			goto _again
-		}
-
-		_acts = int(_expression_trans_actions[_trans])
-		_nacts = uint(_expression_actions[_acts])
-		_acts++
-		for ; _nacts > 0; _nacts-- {
-			_acts++
-			switch _expression_actions[_acts-1] {
-			case 2:
-//line NONE:1
-				lex.te = (lex.p) + 1
-
-			case 3:
-//line scanner.rl:59
-				lex.act = 2
-			case 4:
-//line scanner.rl:76
-				lex.act = 3
-			case 5:
-//line scanner.rl:40
-				lex.act = 4
-			case 6:
-//line scanner.rl:68
-				lex.act = 7
-			case 7:
-//line scanner.rl:45
-				lex.act = 8
-			case 8:
-//line scanner.rl:83
-				lex.act = 10
-			case 9:
-//line scanner.rl:76
-				lex.te = (lex.p) + 1
-				{
-					tok = int(lex.data[lex.ts])
-					(lex.p)++
-					goto _out
-				}
-			case 10:
-//line scanner.rl:78
-				lex.te = (lex.p) + 1
-				{
-					tok = EQ
-					(lex.p)++
-					goto _out
-				}
-			case 11:
-//line scanner.rl:68
-				lex.te = (lex.p) + 1
-				{
-					tok = RELATION
-					out.name = lex.token()
-					(lex.p)++
-					goto _out
-				}
-			case 12:
-//line scanner.rl:83
-				lex.te = (lex.p) + 1
-				{
-					tok = int(lex.data[lex.ts])
-					(lex.p)++
-					goto _out
-				}
-			case 13:
-//line scanner.rl:50
-				lex.te = (lex.p)
-				(lex.p)--
-				{
-					tok = LITERAL
-					n, err := strconv.ParseInt(lex.token(), 10, 64)
-					if err != nil {
-						panic(err)
-					}
-					out.val = int(n)
-					(lex.p)++
-					goto _out
-
-				}
-			case 14:
-//line scanner.rl:45
-				lex.te = (lex.p)
-				(lex.p)--
-				{
-					tok = IDENTIFIER
-					out.name = lex.token()
-					(lex.p)++
-					goto _out
-
-				}
-			case 15:
-//line scanner.rl:82
-				lex.te = (lex.p)
-				(lex.p)--
-
-			case 16:
-//line scanner.rl:83
-				lex.te = (lex.p)
-				(lex.p)--
-				{
-					tok = int(lex.data[lex.ts])
-					(lex.p)++
-					goto _out
-				}
-			case 17:
-//line scanner.rl:83
-				(lex.p) = (lex.te) - 1
-				{
-					tok = int(lex.data[lex.ts])
-					(lex.p)++
-					goto _out
-				}
-			case 18:
-//line NONE:1
-				switch lex.act {
-				case 2:
-					{
-						(lex.p) = (lex.te) - 1
-
-						tok = LITERAL
-						n, err := strconv.ParseFloat(lex.token(), 64)
-						if err != nil {
-							panic(err)
-						}
-						out.val = n
-						(lex.p)++
-						goto _out
-
-					}
-				case 3:
-					{
-						(lex.p) = (lex.te) - 1
-						tok = int(lex.data[lex.ts])
-						(lex.p)++
-						goto _out
-					}
-				case 4:
-					{
-						(lex.p) = (lex.te) - 1
-
-						tok = LITERAL
-						out.val = lex.token() == "true"
-						(lex.p)++
-						goto _out
-
-					}
-				case 7:
-					{
-						(lex.p) = (lex.te) - 1
-						tok = RELATION
-						out.name = lex.token()
-						(lex.p)++
-						goto _out
-					}
-				case 8:
-					{
-						(lex.p) = (lex.te) - 1
-
-						tok = IDENTIFIER
-						out.name = lex.token()
-						(lex.p)++
-						goto _out
-
-					}
-				case 10:
-					{
-						(lex.p) = (lex.te) - 1
-						tok = int(lex.data[lex.ts])
-						(lex.p)++
-						goto _out
-					}
-				}
-
-//line scanner.go:393
-			}
-		}
-
-	_again:
-		_acts = int(_expression_to_state_actions[lex.cs])
-		_nacts = uint(_expression_actions[_acts])
-		_acts++
-		for ; _nacts > 0; _nacts-- {
-			_acts++
-			switch _expression_actions[_acts-1] {
-			case 0:
-//line NONE:1
-				lex.ts = 0
-
-//line scanner.go:407
-			}
-		}
-
-		(lex.p)++
-		if (lex.p) != (lex.pe) {
-			goto _resume
-		}
-	_test_eof:
-		{
-		}
-		if (lex.p) == eof {
-			if _expression_eof_trans[lex.cs] > 0 {
-				_trans = int(_expression_eof_trans[lex.cs] - 1)
-				goto _eof_trans
-			}
-		}
-
-	_out:
-		{
+//line scanner.go:200
 		}
 	}
 
+	_keys = int(_expression_key_offsets[ lex.cs])
+	_trans = int(_expression_index_offsets[ lex.cs])
+
+	_klen = int(_expression_single_lengths[ lex.cs])
+	if _klen > 0 {
+		_lower := int(_keys)
+		var _mid int
+		_upper := int(_keys + _klen - 1)
+		for {
+			if _upper < _lower {
+				break
+			}
+
+			_mid = _lower + ((_upper - _lower) >> 1)
+			switch {
+			case  lex.data[( lex.p)] < _expression_trans_keys[_mid]:
+				_upper = _mid - 1
+			case  lex.data[( lex.p)] > _expression_trans_keys[_mid]:
+				_lower = _mid + 1
+			default:
+				_trans += int(_mid - int(_keys))
+				goto _match
+			}
+		}
+		_keys += _klen
+		_trans += _klen
+	}
+
+	_klen = int(_expression_range_lengths[ lex.cs])
+	if _klen > 0 {
+		_lower := int(_keys)
+		var _mid int
+		_upper := int(_keys + (_klen << 1) - 2)
+		for {
+			if _upper < _lower {
+				break
+			}
+
+			_mid = _lower + (((_upper - _lower) >> 1) & ^1)
+			switch {
+			case  lex.data[( lex.p)] < _expression_trans_keys[_mid]:
+				_upper = _mid - 2
+			case  lex.data[( lex.p)] > _expression_trans_keys[_mid + 1]:
+				_lower = _mid + 2
+			default:
+				_trans += int((_mid - int(_keys)) >> 1)
+				goto _match
+			}
+		}
+		_trans += _klen
+	}
+
+_match:
+	_trans = int(_expression_indicies[_trans])
+_eof_trans:
+	 lex.cs = int(_expression_trans_targs[_trans])
+
+	if _expression_trans_actions[_trans] == 0 {
+		goto _again
+	}
+
+	_acts = int(_expression_trans_actions[_trans])
+	_nacts = uint(_expression_actions[_acts]); _acts++
+	for ; _nacts > 0; _nacts-- {
+		_acts++
+		switch _expression_actions[_acts-1] {
+		case 2:
+//line NONE:1
+ lex.te = ( lex.p)+1
+
+		case 3:
+//line scanner.rl:59
+ lex.act = 2;
+		case 4:
+//line scanner.rl:40
+ lex.act = 4;
+		case 5:
+//line scanner.rl:86
+ lex.act = 5;
+		case 6:
+//line scanner.rl:74
+ lex.act = 8;
+		case 7:
+//line scanner.rl:45
+ lex.act = 9;
+		case 8:
+//line scanner.rl:92
+ lex.act = 11;
+		case 9:
+//line scanner.rl:68
+ lex.te = ( lex.p)+1
+{
+			tok = LITERAL
+			// TODO unescape \x
+			out.val = string(lex.data[lex.ts+1:lex.te-1])
+			( lex.p)++; goto _out
+
+		}
+		case 10:
+//line scanner.rl:86
+ lex.te = ( lex.p)+1
+{ tok = int(lex.data[lex.ts]); ( lex.p)++; goto _out
+ }
+		case 11:
 //line scanner.rl:87
+ lex.te = ( lex.p)+1
+{ tok = EQ; ( lex.p)++; goto _out
+ }
+		case 12:
+//line scanner.rl:74
+ lex.te = ( lex.p)+1
+{ tok = RELATION; out.name = lex.token(); ( lex.p)++; goto _out
+ }
+		case 13:
+//line scanner.rl:92
+ lex.te = ( lex.p)+1
+{ tok = int(lex.data[lex.ts]); ( lex.p)++; goto _out
+ }
+		case 14:
+//line scanner.rl:50
+ lex.te = ( lex.p)
+( lex.p)--
+{
+			tok = LITERAL
+			n, err := strconv.ParseInt(lex.token(), 10, 64)
+			if err != nil {
+				panic(err)
+			}
+			out.val = int(n)
+			( lex.p)++; goto _out
+
+		}
+		case 15:
+//line scanner.rl:45
+ lex.te = ( lex.p)
+( lex.p)--
+{
+			tok = IDENTIFIER
+			out.name = lex.token()
+			( lex.p)++; goto _out
+
+		}
+		case 16:
+//line scanner.rl:91
+ lex.te = ( lex.p)
+( lex.p)--
+
+		case 17:
+//line scanner.rl:92
+ lex.te = ( lex.p)
+( lex.p)--
+{ tok = int(lex.data[lex.ts]); ( lex.p)++; goto _out
+ }
+		case 18:
+//line scanner.rl:92
+( lex.p) = ( lex.te) - 1
+{ tok = int(lex.data[lex.ts]); ( lex.p)++; goto _out
+ }
+		case 19:
+//line NONE:1
+	switch  lex.act {
+	case 2:
+	{( lex.p) = ( lex.te) - 1
+
+			tok = LITERAL
+			n, err := strconv.ParseFloat(lex.token(), 64)
+			if err != nil {
+				panic(err)
+			}
+			out.val = n
+			( lex.p)++; goto _out
+
+		}
+	case 4:
+	{( lex.p) = ( lex.te) - 1
+
+			tok = LITERAL
+			out.val = lex.token() == "true"
+			( lex.p)++; goto _out
+
+		}
+	case 5:
+	{( lex.p) = ( lex.te) - 1
+ tok = int(lex.data[lex.ts]); ( lex.p)++; goto _out
+ }
+	case 8:
+	{( lex.p) = ( lex.te) - 1
+ tok = RELATION; out.name = lex.token(); ( lex.p)++; goto _out
+ }
+	case 9:
+	{( lex.p) = ( lex.te) - 1
+
+			tok = IDENTIFIER
+			out.name = lex.token()
+			( lex.p)++; goto _out
+
+		}
+	case 11:
+	{( lex.p) = ( lex.te) - 1
+ tok = int(lex.data[lex.ts]); ( lex.p)++; goto _out
+ }
+	}
+	
+//line scanner.go:407
+		}
+	}
+
+_again:
+	_acts = int(_expression_to_state_actions[ lex.cs])
+	_nacts = uint(_expression_actions[_acts]); _acts++
+	for ; _nacts > 0; _nacts-- {
+		_acts++
+		switch _expression_actions[_acts-1] {
+		case 0:
+//line NONE:1
+ lex.ts = 0
+
+//line scanner.go:421
+		}
+	}
+
+	( lex.p)++
+	if ( lex.p) != ( lex.pe) {
+		goto _resume
+	}
+	_test_eof: {}
+	if ( lex.p) == eof {
+		if _expression_eof_trans[ lex.cs] > 0 {
+			_trans = int(_expression_eof_trans[ lex.cs] - 1)
+			goto _eof_trans
+		}
+	}
+
+	_out: {}
+	}
+
+//line scanner.rl:96
+
+
 	return tok
 }
 
 func (lex *lexer) Error(e string) {
-	fmt.Println("error:", e)
-}
+    fmt.Println("error:", e)
+}
\ No newline at end of file
diff --git a/expressions/scanner.rl b/expressions/scanner.rl
index 15f7dc9..9043eb4 100644
--- a/expressions/scanner.rl
+++ b/expressions/scanner.rl
@@ -65,16 +65,25 @@ func (lex *lexer) Lex(out *yySymType) int {
 			out.val = n
 			fbreak;
 		}
+		action String {
+			tok = LITERAL
+			// TODO unescape \x
+			out.val = string(lex.data[lex.ts+1:lex.te-1])
+			fbreak;
+		}
 		action Relation { tok = RELATION; out.name = lex.token(); fbreak; }
 
 		ident = (alpha | '_') . (alnum | '_')* ;
-		float = '-'? (digit+ '.' digit* | '.' digit+);
+		int = '-'? digit+ ;
+		float = '-'? (digit+ '.' digit* | '.' digit+) ;
+		string = '"' (any - '"')* '"' | "'" (any - "'")* "'" ; # TODO escapes
 
 		main := |*
-			'-'? digit+ => Int;
+			int => Int;
 			float => Float;
-			[.;<>] | '[' | ']' => { tok = int(lex.data[lex.ts]); fbreak; };
+			string => String;
 			("true" | "false") => Bool;
+			[.;<>] | '[' | ']' => { tok = int(lex.data[lex.ts]); fbreak; };
 			"==" => { tok = EQ; fbreak; };
 			("!=" | ">" | ">" | ">=" | "<=") => Relation;
 			("and" | "or" | "contains") => Relation;