diff --git a/src/sly/parser/generator/EBNFParserBuilder.cs b/src/sly/parser/generator/EBNFParserBuilder.cs
index 5a277a1f..64e0222b 100644
--- a/src/sly/parser/generator/EBNFParserBuilder.cs
+++ b/src/sly/parser/generator/EBNFParserBuilder.cs
@@ -7,7 +7,8 @@
 using sly.lexer;
 using sly.lexer.fsm;
 using sly.parser.generator.visitor;
-using sly.parser.llparser;
+using sly.parser.llparser.bnf;
+using sly.parser.llparser.ebnf;
 using sly.parser.syntax.grammar;
 
 namespace sly.parser.generator
diff --git a/src/sly/parser/generator/ParserBuilder.cs b/src/sly/parser/generator/ParserBuilder.cs
index 2e33e162..87f2e58c 100644
--- a/src/sly/parser/generator/ParserBuilder.cs
+++ b/src/sly/parser/generator/ParserBuilder.cs
@@ -8,7 +8,7 @@
 using sly.lexer;
 using sly.lexer.fsm;
 using sly.parser.generator.visitor;
-using sly.parser.llparser;
+using sly.parser.llparser.bnf;
 using sly.parser.parser;
 using sly.parser.syntax.grammar;
 
diff --git a/src/sly/parser/parser/Parser.cs b/src/sly/parser/parser/Parser.cs
index 3fb8cb15..cd125167 100644
--- a/src/sly/parser/parser/Parser.cs
+++ b/src/sly/parser/parser/Parser.cs
@@ -6,7 +6,8 @@
 using sly.lexer;
 using sly.parser.generator;
 using sly.parser.generator.visitor;
-using sly.parser.llparser;
+using sly.parser.llparser.bnf;
+using sly.parser.llparser.ebnf;
 using sly.parser.parser;
 using sly.parser.syntax.grammar;
 using sly.parser.syntax.tree;
diff --git a/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.Expressions.cs b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.Expressions.cs
index 200ac90c..56d4159d 100644
--- a/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.Expressions.cs
+++ b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.Expressions.cs
@@ -2,9 +2,9 @@
 using sly.parser.syntax.grammar;
 using sly.parser.syntax.tree;
 
-namespace sly.parser.llparser;
+namespace sly.parser.llparser.bnf;
 
-public partial class RecursiveDescentSyntaxParser<IN, OUT>
+public partial class RecursiveDescentSyntaxParser<IN, OUT> where IN : struct
 {
     
             protected SyntaxNode<IN> ManageExpressionRules(Rule<IN> rule, SyntaxNode<IN> node)
diff --git a/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.NonTerminal.cs b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.NonTerminal.cs
index 2c96e464..e05a1dc3 100644
--- a/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.NonTerminal.cs
+++ b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.NonTerminal.cs
@@ -2,9 +2,9 @@
 using sly.lexer;
 using sly.parser.syntax.grammar;
 
-namespace sly.parser.llparser;
+namespace sly.parser.llparser.bnf;
 
-public partial class RecursiveDescentSyntaxParser<IN, OUT>
+public partial class RecursiveDescentSyntaxParser<IN, OUT> where IN : struct
 {
     #region parsing
 
diff --git a/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.Terminal.cs b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.Terminal.cs
index b92b6b2f..ce174426 100644
--- a/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.Terminal.cs
+++ b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.Terminal.cs
@@ -3,9 +3,9 @@
 using sly.parser.syntax.grammar;
 using sly.parser.syntax.tree;
 
-namespace sly.parser.llparser;
+namespace sly.parser.llparser.bnf;
 
-public partial class RecursiveDescentSyntaxParser<IN, OUT>
+public partial class RecursiveDescentSyntaxParser<IN, OUT> where IN : struct
 {
     #region parsing
 
diff --git a/src/sly/parser/parser/llparser/RecursiveDescentSyntaxParser.cs b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.cs
similarity index 99%
rename from src/sly/parser/parser/llparser/RecursiveDescentSyntaxParser.cs
rename to src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.cs
index 9ae3a119..e1f719bc 100644
--- a/src/sly/parser/parser/llparser/RecursiveDescentSyntaxParser.cs
+++ b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParser.cs
@@ -5,7 +5,7 @@
 using sly.parser.syntax.tree;
 using System.Linq;
 
-namespace sly.parser.llparser
+namespace sly.parser.llparser.bnf
 {
     public partial class RecursiveDescentSyntaxParser<IN, OUT> where IN : struct
     {
diff --git a/src/sly/parser/parser/llparser/RecursiveDescentSyntaxParserStarter.cs b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParserStarter.cs
similarity index 99%
rename from src/sly/parser/parser/llparser/RecursiveDescentSyntaxParserStarter.cs
rename to src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParserStarter.cs
index 55dd8931..7cdb766b 100644
--- a/src/sly/parser/parser/llparser/RecursiveDescentSyntaxParserStarter.cs
+++ b/src/sly/parser/parser/llparser/bnf/RecursiveDescentSyntaxParserStarter.cs
@@ -3,7 +3,7 @@
 using sly.parser.generator;
 using sly.parser.syntax.grammar;
 
-namespace sly.parser.llparser
+namespace sly.parser.llparser.bnf
 {
     public partial class RecursiveDescentSyntaxParser<IN, OUT> : ISyntaxParser<IN, OUT> where IN : struct
     {
diff --git a/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.EBNFRecursiveDescentSyntaxParser.Choice.cs b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.EBNFRecursiveDescentSyntaxParser.Choice.cs
index b5096264..5c2f949f 100644
--- a/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.EBNFRecursiveDescentSyntaxParser.Choice.cs
+++ b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.EBNFRecursiveDescentSyntaxParser.Choice.cs
@@ -2,12 +2,13 @@
 using System.Collections.Generic;
 using System.Linq;
 using sly.lexer;
+using sly.parser;
 using sly.parser.syntax.grammar;
 using sly.parser.syntax.tree;
 
-namespace sly.parser.llparser;
+namespace sly.parser.llparser.ebnf;
 
-public partial class EBNFRecursiveDescentSyntaxParser<IN, OUT>
+public partial class EBNFRecursiveDescentSyntaxParser<IN, OUT> where IN : struct
 {
     #region parsing
 
diff --git a/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Expressions.cs b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Expressions.cs
index f74256e9..7a0d2f99 100644
--- a/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Expressions.cs
+++ b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Expressions.cs
@@ -1,9 +1,10 @@
 using System.Collections.Generic;
 using sly.lexer;
+using sly.parser;
 using sly.parser.syntax.grammar;
 using sly.parser.syntax.tree;
 
-namespace sly.parser.llparser;
+namespace sly.parser.llparser.ebnf;
 
 public partial class EBNFRecursiveDescentSyntaxParser<IN, OUT>
 {
diff --git a/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Many.cs b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Many.cs
index 12aa6aea..05ad9a74 100644
--- a/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Many.cs
+++ b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Many.cs
@@ -4,9 +4,9 @@
 using sly.parser.syntax.grammar;
 using sly.parser.syntax.tree;
 
-namespace sly.parser.llparser;
+namespace sly.parser.llparser.ebnf;
 
-public partial class EBNFRecursiveDescentSyntaxParser<IN, OUT>
+public partial class EBNFRecursiveDescentSyntaxParser<IN, OUT> where IN : struct
 {
     #region parsing
 
diff --git a/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Option.cs b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Option.cs
index bff652e4..e2efbe28 100644
--- a/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Option.cs
+++ b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.Option.cs
@@ -4,9 +4,9 @@
 using sly.parser.syntax.grammar;
 using sly.parser.syntax.tree;
 
-namespace sly.parser.llparser;
+namespace sly.parser.llparser.ebnf;
 
-public partial class EBNFRecursiveDescentSyntaxParser<IN, OUT>
+public partial class EBNFRecursiveDescentSyntaxParser<IN, OUT> where IN : struct
 {
     #region parsing
 
diff --git a/src/sly/parser/parser/llparser/EBNFRecursiveDescentSyntaxParser.cs b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.cs
similarity index 99%
rename from src/sly/parser/parser/llparser/EBNFRecursiveDescentSyntaxParser.cs
rename to src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.cs
index 5f88d977..e5bc8550 100644
--- a/src/sly/parser/parser/llparser/EBNFRecursiveDescentSyntaxParser.cs
+++ b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParser.cs
@@ -5,8 +5,9 @@
 using sly.parser.generator;
 using sly.parser.syntax.tree;
 using sly.parser.syntax.grammar;
+using sly.parser.llparser.bnf;
 
-namespace sly.parser.llparser
+namespace sly.parser.llparser.ebnf
 {
     public partial  class EBNFRecursiveDescentSyntaxParser<IN, OUT> : RecursiveDescentSyntaxParser<IN, OUT> where IN : struct
     {
diff --git a/src/sly/parser/parser/llparser/EBNFRecursiveDescentSyntaxParserStarter.cs b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParserStarter.cs
similarity index 99%
rename from src/sly/parser/parser/llparser/EBNFRecursiveDescentSyntaxParserStarter.cs
rename to src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParserStarter.cs
index 120e9306..8dfcfcd2 100644
--- a/src/sly/parser/parser/llparser/EBNFRecursiveDescentSyntaxParserStarter.cs
+++ b/src/sly/parser/parser/llparser/ebnf/EBNFRecursiveDescentSyntaxParserStarter.cs
@@ -2,8 +2,9 @@
 using System.Linq;
 using sly.parser.generator;
 using sly.parser.syntax.grammar;
+using sly.parser.llparser.bnf;
 
-namespace sly.parser.llparser
+namespace sly.parser.llparser.ebnf
 {
     public partial class EBNFRecursiveDescentSyntaxParser<IN, OUT> where IN : struct
     {
diff --git a/tests/ParserTests/EBNFTests.cs b/tests/ParserTests/EBNFTests.cs
index d23c5684..d8ce7713 100644
--- a/tests/ParserTests/EBNFTests.cs
+++ b/tests/ParserTests/EBNFTests.cs
@@ -12,7 +12,7 @@
 using sly.lexer;
 using sly.parser;
 using sly.parser.generator;
-using sly.parser.llparser;
+using sly.parser.llparser.ebnf;
 using sly.parser.parser;
 using sly.parser.syntax.grammar;
 using Xunit;