diff --git a/boot.go b/boot.go
index 0f5c932..f454552 100644
--- a/boot.go
+++ b/boot.go
@@ -97,7 +97,7 @@ func parseClass(class []rune) (not bool, chars []rune, ranges [][]rune, err erro
 
 func defineBootAnything(s *Syntax, d []string) error {
 	ct := stringToCommitType(d[2])
-	return s.AnyChar(d[1], ct)
+	return s.anyChar(d[1], ct)
 }
 
 func defineBootClass(s *Syntax, d []string) error {
@@ -109,7 +109,7 @@ func defineBootClass(s *Syntax, d []string) error {
 		return err
 	}
 
-	return s.Class(name, ct, not, chars, ranges)
+	return s.class(name, ct, not, chars, ranges)
 }
 
 func defineBootCharSequence(s *Syntax, d []string) error {
@@ -121,7 +121,7 @@ func defineBootCharSequence(s *Syntax, d []string) error {
 		return err
 	}
 
-	return s.CharSequence(name, ct, chars)
+	return s.charSequence(name, ct, chars)
 }
 
 func splitQuantifiedSymbol(s string) (string, int, int) {
@@ -159,14 +159,14 @@ func defineBootSequence(s *Syntax, defs []string) error {
 	name := defs[1]
 	ct := stringToCommitType(defs[2])
 	items := namesToSequenceItemsQuantify(defs[3:])
-	return s.Sequence(name, ct, items...)
+	return s.sequence(name, ct, items...)
 }
 
 func defineBootChoice(s *Syntax, defs []string) error {
 	name := defs[1]
 	ct := stringToCommitType(defs[2])
 	items := defs[3:]
-	return s.Choice(name, ct, items...)
+	return s.choice(name, ct, items...)
 }
 
 func defineBoot(s *Syntax, defs []string) error {
@@ -197,7 +197,7 @@ func defineAllBoot(s *Syntax, defs [][]string) error {
 }
 
 func createBoot() (*Syntax, error) {
-	s := NewSyntax()
+	s := &Syntax{}
 	if err := defineAllBoot(s, bootSyntaxDefs); err != nil {
 		return nil, err
 	}
@@ -211,7 +211,7 @@ func bootSyntax() (*Syntax, error) {
 		return nil, err
 	}
 
-	f, err := os.Open("treerack.treerack")
+	f, err := os.Open("syntax.treerack")
 	if err != nil {
 		return nil, err
 	}
@@ -223,6 +223,6 @@ func bootSyntax() (*Syntax, error) {
 		return nil, err
 	}
 
-	s := NewSyntax()
+	s := &Syntax{}
 	return s, define(s, doc)
 }
diff --git a/boot_test.go b/boot_test.go
index eab4746..ad6523b 100644
--- a/boot_test.go
+++ b/boot_test.go
@@ -15,7 +15,7 @@ func parseWithSyntax(s *Syntax, f io.ReadSeeker) (*Node, error) {
 }
 
 func syntaxFromTree(n *Node) (*Syntax, error) {
-	s := NewSyntax()
+	s := &Syntax{}
 	if err := define(s, n); err != nil {
 		return nil, err
 	}
@@ -51,7 +51,7 @@ func TestBoot(t *testing.T) {
 		return
 	}
 
-	f, err := os.Open("treerack.treerack")
+	f, err := os.Open("syntax.treerack")
 	if err != nil {
 		t.Error(err)
 		return
diff --git a/bootsyntax.go b/bootsyntax.go
index 0c3b25d..6668c11 100644
--- a/bootsyntax.go
+++ b/bootsyntax.go
@@ -135,7 +135,7 @@ var bootSyntaxDefs = [][]string{{
 }, {
 	"choice", "terminal", "alias", "any-char", "char-class", "char-sequence",
 }, {
-	"class", "symbol-char", "alias", "^\\\\ \\n\\t\\b\\f\\r\\v\\b/.\\[\\]\\\"{}\\^+*?|():=;",
+	"class", "symbol-char", "alias", symbolChars,
 }, {
 	"sequence", "symbol-chars", "alias", "symbol-char:1:-1",
 }, {
diff --git a/char.go b/char.go
index 8e100cb..467a25c 100644
--- a/char.go
+++ b/char.go
@@ -56,20 +56,24 @@ func (p *charParser) builder() builder {
 	return p
 }
 
+func matchChars(chars []rune, ranges [][]rune, not bool, char rune) bool {
+	for _, ci := range chars {
+		if ci == char {
+			return !not
+		}
+	}
+
+	for _, ri := range ranges {
+		if char >= ri[0] && char <= ri[1] {
+			return !not
+		}
+	}
+
+	return not
+}
+
 func (p *charParser) match(t rune) bool {
-	for _, ci := range p.chars {
-		if ci == t {
-			return !p.not
-		}
-	}
-
-	for _, ri := range p.ranges {
-		if t >= ri[0] && t <= ri[1] {
-			return !p.not
-		}
-	}
-
-	return p.not
+	return matchChars(p.chars, p.ranges, p.not, t)
 }
 
 func (p *charParser) parse(c *context) {
@@ -86,17 +90,4 @@ func (p *charParser) parse(c *context) {
 
 func (p *charParser) build(c *context) ([]*Node, bool) {
 	panic("called char build")
-	// // TODO: how to remove this check
-	// t, ok := c.token()
-	// if !ok {
-	// 	panic("damaged parser context")
-	// }
-
-	// if !p.match(t) {
-	// 	return nil, false
-	// }
-
-	// // always alias
-	// c.offset++
-	// return nil, true
 }
diff --git a/define.go b/define.go
index 4af7927..12bf599 100644
--- a/define.go
+++ b/define.go
@@ -95,7 +95,7 @@ func defineClass(s *Syntax, name string, ct CommitType, n []*Node) error {
 		}
 	}
 
-	return s.Class(name, ct, not, chars, ranges)
+	return s.class(name, ct, not, chars, ranges)
 }
 
 func defineCharSequence(s *Syntax, name string, ct CommitType, charNodes []*Node) error {
@@ -104,7 +104,7 @@ func defineCharSequence(s *Syntax, name string, ct CommitType, charNodes []*Node
 		chars = append(chars, nodeChar(ci))
 	}
 
-	return s.CharSequence(name, ct, chars)
+	return s.charSequence(name, ct, chars)
 }
 
 func getQuantity(n *Node) (min int, max int, err error) {
@@ -148,7 +148,7 @@ func getQuantity(n *Node) (min int, max int, err error) {
 }
 
 func defineSymbol(s *Syntax, name string, ct CommitType, n *Node) error {
-	return s.Sequence(name, ct, SequenceItem{Name: n.Text()})
+	return s.sequence(name, ct, SequenceItem{Name: n.Text()})
 }
 
 func defineSequence(s *Syntax, name string, ct CommitType, n ...*Node) error {
@@ -180,7 +180,7 @@ func defineSequence(s *Syntax, name string, ct CommitType, n ...*Node) error {
 		items = append(items, item)
 	}
 
-	return s.Sequence(name, ct, items...)
+	return s.sequence(name, ct, items...)
 }
 
 func defineChoice(s *Syntax, name string, ct CommitType, n ...*Node) error {
@@ -190,14 +190,14 @@ func defineChoice(s *Syntax, name string, ct CommitType, n ...*Node) error {
 		return err
 	}
 
-	return s.Choice(name, ct, refs...)
+	return s.choice(name, ct, refs...)
 }
 
 func defineExpression(s *Syntax, name string, ct CommitType, expression *Node) error {
 	var err error
 	switch expression.Name {
 	case "any-char":
-		err = s.AnyChar(name, ct)
+		err = s.anyChar(name, ct)
 	case "char-class":
 		err = defineClass(s, name, ct, expression.Nodes)
 	case "char-sequence":
diff --git a/open_test.go b/open_test.go
index 960237d..b439c29 100644
--- a/open_test.go
+++ b/open_test.go
@@ -17,7 +17,7 @@ func openSyntaxReader(r io.Reader) (*Syntax, error) {
 		return nil, err
 	}
 
-	s := NewSyntax()
+	s := &Syntax{}
 	if err := define(s, doc); err != nil {
 		return nil, err
 	}
diff --git a/parse_test.go b/parse_test.go
index af5ee88..43edb4c 100644
--- a/parse_test.go
+++ b/parse_test.go
@@ -573,7 +573,7 @@ func TestUndefined(t *testing.T) {
 		t.Error(err)
 	}
 
-	stest := NewSyntax()
+	stest := &Syntax{}
 	err = define(stest, n)
 	if err != nil {
 		t.Error(err)
diff --git a/syntax.go b/syntax.go
index 31692b8..4921744 100644
--- a/syntax.go
+++ b/syntax.go
@@ -46,16 +46,36 @@ var (
 	ErrRootWhitespace          = errors.New("root node cannot be a whitespace")
 	ErrNotImplemented          = errors.New("not implemented")
 	ErrMultipleRoots           = errors.New("multiple roots")
+	ErrInvalidSymbolName       = errors.New("invalid symbol name")
 )
 
+const symbolChars = "^\\\\ \\n\\t\\b\\f\\r\\v/.\\[\\]\\\"{}\\^+*?|():=;"
+
+func parseSymbolChars(c []rune) []rune {
+	_, chars, _, err := parseClass(c)
+	if err != nil {
+		panic(err)
+	}
+
+	return chars
+}
+
+var symbolCharRunes = parseSymbolChars([]rune(symbolChars))
+
 func duplicateDefinition(name string) error {
 	return fmt.Errorf("duplicate definition: %s", name)
 }
 
-func NewSyntax() *Syntax {
-	return &Syntax{
-		registry: newRegistry(),
+func isValidSymbol(n string) bool {
+	runes := []rune(n)
+	for _, r := range runes {
+		if !matchChars(symbolCharRunes, nil, true, r) {
+			return false
+		}
 	}
+
+	return true
+
 }
 
 func (s *Syntax) register(d definition) error {
@@ -63,6 +83,10 @@ func (s *Syntax) register(d definition) error {
 		return ErrSyntaxInitialized
 	}
 
+	if s.registry == nil {
+		s.registry = newRegistry()
+	}
+
 	if d.commitType()&Root != 0 {
 		if s.explicitRoot {
 			return ErrMultipleRoots
@@ -90,8 +114,16 @@ func (s *Syntax) register(d definition) error {
 	return s.registry.setDefinition(d)
 }
 
+func (s *Syntax) anyChar(name string, ct CommitType) error {
+	return s.class(name, ct, true, nil, nil)
+}
+
 func (s *Syntax) AnyChar(name string, ct CommitType) error {
-	return s.Class(name, ct, true, nil, nil)
+	if !isValidSymbol(name) {
+		return ErrInvalidSymbolName
+	}
+
+	return s.anyChar(name, ct)
 }
 
 func childName(name string, childIndex int) string {
@@ -107,16 +139,24 @@ func namesToSequenceItems(n []string) []SequenceItem {
 	return si
 }
 
-func (s *Syntax) Class(name string, ct CommitType, not bool, chars []rune, ranges [][]rune) error {
+func (s *Syntax) class(name string, ct CommitType, not bool, chars []rune, ranges [][]rune) error {
 	cname := childName(name, 0)
 	if err := s.register(newChar(cname, not, chars, ranges)); err != nil {
 		return err
 	}
 
-	return s.Sequence(name, ct, SequenceItem{Name: cname})
+	return s.sequence(name, ct, SequenceItem{Name: cname})
 }
 
-func (s *Syntax) CharSequence(name string, ct CommitType, chars []rune) error {
+func (s *Syntax) Class(name string, ct CommitType, not bool, chars []rune, ranges [][]rune) error {
+	if !isValidSymbol(name) {
+		return ErrInvalidSymbolName
+	}
+
+	return s.class(name, ct, not, chars, ranges)
+}
+
+func (s *Syntax) charSequence(name string, ct CommitType, chars []rune) error {
 	var refs []string
 	for i, ci := range chars {
 		ref := childName(name, i)
@@ -126,17 +166,41 @@ func (s *Syntax) CharSequence(name string, ct CommitType, chars []rune) error {
 		}
 	}
 
-	return s.Sequence(name, ct|NoWhitespace, namesToSequenceItems(refs)...)
+	return s.sequence(name, ct|NoWhitespace, namesToSequenceItems(refs)...)
 }
 
-func (s *Syntax) Sequence(name string, ct CommitType, items ...SequenceItem) error {
+func (s *Syntax) CharSequence(name string, ct CommitType, chars []rune) error {
+	if !isValidSymbol(name) {
+		return ErrInvalidSymbolName
+	}
+
+	return s.charSequence(name, ct, chars)
+}
+
+func (s *Syntax) sequence(name string, ct CommitType, items ...SequenceItem) error {
 	return s.register(newSequence(name, ct, items))
 }
 
-func (s *Syntax) Choice(name string, ct CommitType, elements ...string) error {
+func (s *Syntax) Sequence(name string, ct CommitType, items ...SequenceItem) error {
+	if !isValidSymbol(name) {
+		return ErrInvalidSymbolName
+	}
+
+	return s.sequence(name, ct, items...)
+}
+
+func (s *Syntax) choice(name string, ct CommitType, elements ...string) error {
 	return s.register(newChoice(name, ct, elements))
 }
 
+func (s *Syntax) Choice(name string, ct CommitType, elements ...string) error {
+	if !isValidSymbol(name) {
+		return ErrInvalidSymbolName
+	}
+
+	return s.choice(name, ct, elements...)
+}
+
 func (s *Syntax) Read(r io.Reader) error {
 	if s.initialized {
 		return ErrSyntaxInitialized
diff --git a/treerack.treerack b/syntax.treerack
similarity index 100%
rename from treerack.treerack
rename to syntax.treerack