diff --git a/lib/ebnf.ex b/lib/ebnf.ex
index ae5ccfe..541560b 100644
--- a/lib/ebnf.ex
+++ b/lib/ebnf.ex
@@ -136,6 +136,45 @@ defmodule EBNF do
     group_alternates(rest, alternates, [factor | current_group])
   end
 
+  defp times(factor, times) do
+    1..times//1
+    |> Enum.map(fn _i -> factor end)
+  end
+
+  defp expand_repetition(factor, {:times, [t]}, ids, name) do
+
+    rule = if t > 0 do
+      times(factor, t)
+    else
+      {:empty, []}
+    end
+
+
+    next_symbol_id = map_size(ids)
+    next_rule_name = "#{name}_#{next_symbol_id}"
+    ids = Map.put(ids, next_rule_name, next_symbol_id)
+
+    {next_rule_name, traverse_rule({:rule, [{:identifier, [next_rule_name]} | rule ]}, ids, name)}
+  end
+
+  defp expand_repetition(factor, {:from_to, [from, to]}, ids, name) when from <= to do
+
+    from_rules = if from > 0 do
+      times(factor, from)
+    else
+      [{:empty, []}]
+    end
+    to_rules = from+1..to//1
+    |> Enum.reduce([], fn e,acc -> times(factor,e) ++ ["|" | acc] end)
+    next_symbol_id = map_size(ids)
+    next_rule_name = "#{name}_#{next_symbol_id}"
+    ids = Map.put(ids, next_rule_name, next_symbol_id)
+
+    rule = [alternate: to_rules ++ from_rules]
+
+    {next_rule_name, traverse_rule({:rule, [{:identifier, [next_rule_name]} | rule ]}, ids, name)}
+  end
+
   defp expand_repetition(factor, rep, ids, name) do
     next_symbol_id = map_size(ids)
     next_rule_name = "#{name}_#{next_symbol_id}"
diff --git a/lib/ebnf/parser.ex b/lib/ebnf/parser.ex
index aa5bd6c..6370d01 100644
--- a/lib/ebnf/parser.ex
+++ b/lib/ebnf/parser.ex
@@ -2,7 +2,20 @@ defmodule EBNF.Parser do
   @moduledoc false
 
   import NimbleParsec
-  import EBNF.Parser.Helpers
+
+  from_to =
+    ignore(string("{"))
+    |> integer(min: 1)
+    |> ignore(string(","))
+    |> integer(min: 1)
+    |> ignore(string("}"))
+    |> tag(:from_to)
+
+    times =
+      ignore(string("{"))
+      |> integer(min: 1)
+      |> ignore(string("}"))
+      |> tag(:times)
 
   whitespace = repeat(choice([string(" "), string("\n"), string("\t")]))
 
@@ -25,8 +38,16 @@ defmodule EBNF.Parser do
     choice([
       string(~S( )) |> replace(?\s),
       string(~S(\t)) |> replace(?\t),
+      string("\t") |> replace(?\t),
       string(~S(\n)) |> replace(?\n),
+      string("\n") |> replace(?\n),
+      string("\r") |> replace(?\r),
       string(~S(\\)) |> replace(?\\),
+      string("\\") |> replace(?\\),
+      string("\"") |> replace(?\"),
+      string("\d") |> replace(?\d),
+      string("\0") |> replace(?\0),
+      string("\x1F") |> replace(~s(\x1F)),
       ascii_char([?a..?z, ?A..?Z, ?0..?9, ?_, ?-, ?+, ?*, ?/])
     ])
     |> tag(:char)
@@ -37,11 +58,20 @@ defmodule EBNF.Parser do
     |> concat(char)
     |> tag(:range)
 
+
+
   range_or_char = choice([range, char])
 
+  negation =
+    ignore(string("^"))
+    |> concat(range_or_char)
+    |> tag(:negation)
+
+  negation_range_or_char = choice([negation, range, char])
+
   character_set =
     ignore(string("["))
-    |> times(range_or_char, min: 1)
+    |> times(negation_range_or_char, min: 1)
     |> ignore(string("]"))
     |> tag(:character_set)
 
@@ -50,7 +80,7 @@ defmodule EBNF.Parser do
     |> tag(:terminal)
 
   identifier =
-    ascii_string([?a..?z, ?A..?Z, ?0..?9, ?_], min: 1)
+    ascii_string([?a..?z, ?A..?Z, ?0..?9, ?_, ?-], min: 1)
     |> tag(:identifier)
 
   grouping =
@@ -63,10 +93,13 @@ defmodule EBNF.Parser do
 
   factor =
     choice([identifier, terminal, grouping])
-    |> repeatable()
+    |> then(&choice([
+      tag(concat(&1,choice([string("*"), string("+"), string("?"), from_to, times])),:repetition),
+      &1
+    ]))
     |> ignore(repeat(choice([string(" "), string("\t")])))
 
-  term = times(factor, min: 1)
+  term = times(factor, min: 0)
 
   choice_separator =
     ignore(repeat(string(" ")))
diff --git a/lib/ebnf/parser/helpers.ex b/lib/ebnf/parser/helpers.ex
deleted file mode 100644
index eaca069..0000000
--- a/lib/ebnf/parser/helpers.ex
+++ /dev/null
@@ -1,10 +0,0 @@
-defmodule EBNF.Parser.Helpers do
-  import NimbleParsec
-
-  def repeatable(combinator) do
-    choice([
-      tag(concat(combinator, choice([string("*"), string("+"), string("?")])), :repetition),
-      combinator
-    ])
-  end
-end
diff --git a/test/ebnf_more_test.exs b/test/ebnf_more_test.exs
new file mode 100644
index 0000000..5b4cbef
--- /dev/null
+++ b/test/ebnf_more_test.exs
@@ -0,0 +1,914 @@
+#
+# MIT License
+#
+# Copyright (c) 2023-2024 The ggml authors
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+#
+#
+# https://github.com/ggerganov/llama.cpp/blob/master/tests/test-json-schema-to-grammar.cpp
+#
+# Code used from Regex Copy paste from llama.cpp
+#
+defmodule EBNFMoreTest do
+  use ExUnit.Case
+
+  alias EBNF.ParseState
+
+# Try all to parse all grammars from
+# https://github.com/ggerganov/llama.cpp/blob/master/tests/test-json-schema-to-grammar.cpp
+  describe "parse/1" do
+
+    test "min 0" do
+
+	grammar = """
+root ::= ([0] | [1-9] [0-9]{0,15}) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+      assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+      assert [_ | _] = parsed
+    end
+
+    test "min 1" do
+
+	grammar = """
+root ::= ([1-9] [0-9]{0,15}) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min 3" do
+
+	grammar = """
+root ::= ([1-2] [0-9]{1,15} | [3-9] [0-9]{0,15}) space
+space ::= | " "
+"""
+assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min 9" do
+
+	grammar = """
+root ::= ([1-8] [0-9]{1,15} | [9] [0-9]{0,15}) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min 10" do
+
+	grammar = """
+root ::= ([1] ([0-9]{1,15}) | [2-9] [0-9]{1,15}) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min 25" do
+
+	grammar = """
+root ::= ([1] [0-9]{2,15} | [2] ([0-4] [0-9]{1,14} | [5-9] [0-9]{0,14}) | [3-9] [0-9]{1,15}) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "max 30" do
+
+	grammar = """
+root ::= ("-" [1-9] [0-9]{0,15} | [0-9] | ([1-2] [0-9] | [3] "0")) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min -5" do
+
+	grammar = """
+root ::= ("-" ([0-5]) | [0] | [1-9] [0-9]{0,15}) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min -123" do
+
+	grammar = """
+root ::= ("-" ([0-9] | ([1-8] [0-9] | [9] [0-9]) | "1" ([0-1] [0-9] | [2] [0-3])) | [0] | [1-9] [0-9]{0,15}) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "max -5" do
+
+	grammar = """
+root ::= ("-" ([0-4] [0-9]{1,15} | [5-9] [0-9]{0,15})) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "max 1" do
+
+	grammar = """
+root ::= ("-" [1-9] [0-9]{0,15} | [0-1]) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "max 100" do
+
+	grammar = """
+root ::= ("-" [1-9] [0-9]{0,15} | [0-9] | ([1-8] [0-9] | [9] [0-9]) | "100") space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min 0 max 23" do
+
+	grammar = """
+root ::= ([0-9] | ([1] [0-9] | [2] [0-3])) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min 15 max 300" do
+
+	grammar = """
+root ::= (([1] ([5-9]) | [2-9] [0-9]) | ([1-2] [0-9]{2} | [3] "00")) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min 5 max 30" do
+
+	grammar = """
+root ::= ([5-9] | ([1-2] [0-9] | [3] "0")) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min -123 max 42" do
+
+	grammar = """
+root ::= ("-" ([0-9] | ([1-8] [0-9] | [9] [0-9]) | "1" ([0-1] [0-9] | [2] [0-3])) | [0-9] | ([1-3] [0-9] | [4] [0-2])) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min -10 max 10" do
+
+	grammar = """
+root ::= ("-" ([0-9] | "10") | [0-9] | "10") space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+
+    test "empty schema (object)" do
+
+	grammar = """
+array ::= "[" space ( value ("," space value)* )? "]" space
+boolean ::= ("true" | "false") space
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+null ::= "null" space
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+object ::= "{" space ( string ":" space value ("," space string ":" space value)* )? "}" space
+root ::= object
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+value ::= object | array | string | number | boolean | null
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "exotic formats" do
+
+	grammar = """
+date ::= [0-9]{4} "-" ( "0" [1-9] | "1" [0-2] ) "-" ( "0" [1-9] | [1-2] [0-9] | "3" [0-1] )
+date-string ::= "\"" date "\"" space
+date-time ::= date "T" time
+date-time-string ::= "\"" date-time "\"" space
+root ::= "[" space tuple-0 "," space uuid "," space tuple-2 "," space tuple-3 "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+time ::= ([01] [0-9] | "2" [0-3]) ":" [0-5] [0-9] ":" [0-5] [0-9] ( "." [0-9]{3} )? ( "Z" | ( "+" | "-" ) ( [01] [0-9] | "2" [0-3] ) ":" [0-5] [0-9] )
+time-string ::= "\"" time "\"" space
+tuple-0 ::= date-string
+tuple-2 ::= time-string
+tuple-3 ::= date-time-string
+uuid ::= "\"" [0-9a-fA-F]{8} "-" [0-9a-fA-F]{4} "-" [0-9a-fA-F]{4} "-" [0-9a-fA-F]{4} "-" [0-9a-fA-F]{12} "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "string" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "\"" char* "\"" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "string w/ min length 1" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "\"" char+ "\"" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "string w/ min length 3" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "\"" char{3,} "\"" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "string w/ max length" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "\"" char{0,3} "\"" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "string w/ min & max length" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "\"" char{1,4} "\"" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "boolean" do
+
+	grammar = """
+root ::= ("true" | "false") space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "integer" do
+
+	grammar = """
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+root ::= ("-"? integral-part) space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "string const" do
+
+	grammar = """
+root ::= "\"foo\"" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "non-string const" do
+
+	grammar = """
+root ::= "123" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "non-string enum" do
+
+	grammar = """
+root ::= ("\"red\"" | "\"amber\"" | "\"green\"" | "null" | "42" | "[\"foo\"]") space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "string array" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "[" space (string ("," space string)*)? "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "nullable string array" do
+
+	grammar = """
+alternative-0 ::= "[" space (string ("," space string)*)? "]" space
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+null ::= "null" space
+root ::= alternative-0 | null
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "tuple1" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "[" space string "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "tuple2" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+root ::= "[" space string "," space number "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "number" do
+
+	grammar = """
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+root ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "minItems" do
+
+	grammar = """
+boolean ::= ("true" | "false") space
+root ::= "[" space boolean ("," space boolean)+ "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "maxItems 1" do
+
+	grammar = """
+boolean ::= ("true" | "false") space
+root ::= "[" space boolean? "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "maxItems 2" do
+
+	grammar = """
+boolean ::= ("true" | "false") space
+root ::= "[" space (boolean ("," space boolean)?)? "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min + maxItems" do
+
+	grammar = """
+decimal-part ::= [0-9]{1,16}
+integer ::= ("-"? integral-part) space
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+item ::= number | integer
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+root ::= "[" space item ("," space item){2,4} "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min + max items with min + max values across zero" do
+
+	grammar = """
+item ::= ("-" ([0-9] | "1" [0-2]) | [0-9] | ([1-8] [0-9] | [9] [0-9]) | ([1] [0-9]{2} | [2] "0" [0-7])) space
+root ::= "[" space item ("," space item){2,4} "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "min + max items with min + max values" do
+
+	grammar = """
+item ::= (([1] ([2-9]) | [2-9] [0-9]) | ([1] [0-9]{2} | [2] "0" [0-7])) space
+root ::= "[" space item ("," space item){2,4} "]" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "simple regexp" do
+
+	grammar = """
+root ::= "\"" "ab" "c"? "d"* "ef" "g"+ ("hij")? "kl" "\"" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+#    test "regexp escapes" do
+#
+#	grammar = """
+#root ::= "\"" "[]{}()|+*?" "\"" space
+#space ::= | " " | "\n" [ \t]{0,20}
+#"""
+#	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+#assert [_ | _] = parsed
+#    end
+
+#    test "regexp quote" do
+#
+#	grammar = """
+#root ::= "\"" "\"" "\"" space
+#space ::= | " " | "\n" [ \t]{0,20}
+#"""
+#	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+#assert [_ | _] = parsed
+#    end
+
+    test "regexp" do
+
+	grammar = """
+dot ::= [^\x0A\x0D]
+root ::= "\"" ("(" root-1{1,3} ")")? root-1{3,3} "-" root-1{4,4} " " "a"{3,5} "nd" dot dot dot "\"" space
+root-1 ::= [0-9]
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "required props in original order" do
+
+	grammar = """
+a-kv ::= "\"a\"" space ":" space string
+b-kv ::= "\"b\"" space ":" space string
+c-kv ::= "\"c\"" space ":" space string
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "{" space b-kv "," space c-kv "," space a-kv "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "1 optional prop" do
+
+	grammar = """
+a-kv ::= "\"a\"" space ":" space string
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "{" space  (a-kv )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "N optional props" do
+
+	grammar = """
+a-kv ::= "\"a\"" space ":" space string
+a-rest ::= ( "," space b-kv )? b-rest
+b-kv ::= "\"b\"" space ":" space string
+b-rest ::= ( "," space c-kv )?
+c-kv ::= "\"c\"" space ":" space string
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+root ::= "{" space  (a-kv a-rest | b-kv b-rest | c-kv )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "required + optional props each in original order" do
+
+	grammar = """
+a-kv ::= "\"a\"" space ":" space string
+b-kv ::= "\"b\"" space ":" space string
+c-kv ::= "\"c\"" space ":" space string
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+d-kv ::= "\"d\"" space ":" space string
+d-rest ::= ( "," space c-kv )?
+root ::= "{" space b-kv "," space a-kv ( "," space ( d-kv d-rest | c-kv ) )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "additional props" do
+
+	grammar = """
+additional-kv ::= string ":" space additional-value
+additional-value ::= "[" space (number ("," space number)*)? "]" space
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+root ::= "{" space  (additional-kv ( "," space additional-kv )* )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "additional props (true)" do
+
+	grammar = """
+array ::= "[" space ( value ("," space value)* )? "]" space
+boolean ::= ("true" | "false") space
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+null ::= "null" space
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+object ::= "{" space ( string ":" space value ("," space string ":" space value)* )? "}" space
+root ::= object
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+value ::= object | array | string | number | boolean | null
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "additional props (implicit)" do
+
+	grammar = """
+array ::= "[" space ( value ("," space value)* )? "]" space
+boolean ::= ("true" | "false") space
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+null ::= "null" space
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+object ::= "{" space ( string ":" space value ("," space string ":" space value)* )? "}" space
+root ::= object
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+value ::= object | array | string | number | boolean | null
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "empty w/o additional props" do
+
+	grammar = """
+root ::= "{" space  "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "required + additional props" do
+
+	grammar = """
+a-kv ::= "\"a\"" space ":" space number
+additional-k ::= ["] ( [a] char+ | [^"a] char* )? ["] space
+additional-kv ::= additional-k ":" space string
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+root ::= "{" space a-kv ( "," space ( additional-kv ( "," space additional-kv )* ) )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "optional + additional props" do
+
+	grammar = """
+a-kv ::= "\"a\"" space ":" space number
+a-rest ::= ( "," space additional-kv )*
+additional-k ::= ["] ( [a] char+ | [^"a] char* )? ["] space
+additional-kv ::= additional-k ":" space number
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+root ::= "{" space  (a-kv a-rest | additional-kv ( "," space additional-kv )* )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "required + optional + additional props" do
+
+	grammar = """
+additional-k ::= ["] ( [a] ([l] ([s] ([o] char+ | [^"o] char*) | [^"s] char*) | [n] ([d] char+ | [^"d] char*) | [^"ln] char*) | [^"a] char* )? ["] space
+additional-kv ::= additional-k ":" space number
+also-kv ::= "\"also\"" space ":" space number
+also-rest ::= ( "," space additional-kv )*
+and-kv ::= "\"and\"" space ":" space number
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+root ::= "{" space and-kv ( "," space ( also-kv also-rest | additional-kv ( "," space additional-kv )* ) )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "optional props with empty name" do
+
+	grammar = """
+-kv ::= "\"\"" space ":" space root
+-rest ::= ( "," space a-kv )? a-rest
+a-kv ::= "\"a\"" space ":" space integer
+a-rest ::= ( "," space additional-kv )*
+additional-k ::= ["] ( [a] char+ | [^"a] char* ) ["] space
+additional-kv ::= additional-k ":" space integer
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+integer ::= ("-"? integral-part) space
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+root ::= ("-"? integral-part) space
+root0 ::= "{" space  (-kv -rest | a-kv a-rest | additional-kv ( "," space additional-kv )* )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "optional props with nested names" do
+
+	grammar = """
+a-kv ::= "\"a\"" space ":" space integer
+a-rest ::= ( "," space aa-kv )? aa-rest
+aa-kv ::= "\"aa\"" space ":" space integer
+aa-rest ::= ( "," space additional-kv )*
+additional-k ::= ["] ( [a] ([a] char+ | [^"a] char*) | [^"a] char* )? ["] space
+additional-kv ::= additional-k ":" space integer
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+integer ::= ("-"? integral-part) space
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+root ::= "{" space  (a-kv a-rest | aa-kv aa-rest | additional-kv ( "," space additional-kv )* )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "optional props with common prefix" do
+
+	grammar = """
+ab-kv ::= "\"ab\"" space ":" space integer
+ab-rest ::= ( "," space ac-kv )? ac-rest
+ac-kv ::= "\"ac\"" space ":" space integer
+ac-rest ::= ( "," space additional-kv )*
+additional-k ::= ["] ( [a] ([b] char+ | [c] char+ | [^"bc] char*) | [^"a] char* )? ["] space
+additional-kv ::= additional-k ":" space integer
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+integer ::= ("-"? integral-part) space
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+root ::= "{" space  (ab-kv ab-rest | ac-kv ac-rest | additional-kv ( "," space additional-kv )* )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "top-level $ref" do
+
+	grammar = """
+char ::= [^"\\\x7F\x00-\x1F] | [\\] (["\\bfnrt] | "u" [0-9a-fA-F]{4})
+foo ::= "{" space foo-a-kv "}" space
+foo-a-kv ::= "\"a\"" space ":" space string
+root ::= foo
+space ::= | " " | "\n" [ \t]{0,20}
+string ::= "\"" char* "\"" space
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "anyOf" do
+
+	grammar = """
+alternative-0 ::= foo
+alternative-1 ::= bar
+bar ::= "{" space  (bar-b-kv )? "}" space
+bar-b-kv ::= "\"b\"" space ":" space number
+decimal-part ::= [0-9]{1,16}
+foo ::= "{" space  (foo-a-kv )? "}" space
+foo-a-kv ::= "\"a\"" space ":" space number
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+root ::= alternative-0 | alternative-1
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "mix of allOf, anyOf and $ref (similar to https://json.schemastore.org/tsconfig.json)" do
+
+	grammar = """
+a-kv ::= "\"a\"" space ":" space number
+b-kv ::= "\"b\"" space ":" space number
+c-kv ::= "\"c\"" space ":" space number
+d-kv ::= "\"d\"" space ":" space number
+d-rest ::= ( "," space c-kv )?
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+root ::= "{" space a-kv "," space b-kv ( "," space ( d-kv d-rest | c-kv ) )? "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "conflicting names" do
+
+	grammar = """
+decimal-part ::= [0-9]{1,16}
+integral-part ::= [0] | [1-9] [0-9]{0,15}
+number ::= ("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space
+number- ::= "{" space number-number-kv "}" space
+number-kv ::= "\"number\"" space ":" space number-
+number-number ::= "{" space number-number-root-kv "}" space
+number-number-kv ::= "\"number\"" space ":" space number-number
+number-number-root-kv ::= "\"root\"" space ":" space number
+root ::= "{" space number-kv "}" space
+space ::= | " " | "\n" [ \t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "tab" do
+
+	grammar = """
+root ::= [\t]{0,20}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "two tab" do
+
+	grammar = """
+root ::= [\t]{2}
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+    test "char regex" do
+
+	grammar = """
+root ::= [^\"\\\d\0-\x1F]
+"""
+	assert {:ok, parsed, "", _, _, _} = EBNF.parse(grammar)
+assert [_ | _] = parsed
+    end
+
+  end
+
+  describe "expand/1" do
+
+    test "tab{1,3}" do
+
+	grammar = """
+root ::= [\t]{1,3}
+"""
+assert %ParseState{
+         symbol_ids: symbol,
+         grammar_encoding: encoded
+       } = EBNF.encode(grammar)
+assert [1, 10, 2, 9, 9, 2, 9, 9, 2, 9, 9, 0, 7, 2, 9, 9, 2, 9, 9, 0, 4, 2, 9, 9, 0, 0, 0, 3, 1, 1, 0, 0, 65535] = encoded
+assert %{"root" => 0, "root_1" => 1} = symbol
+    end
+
+    test "tab{0,3}" do
+
+	grammar = """
+root ::= [\t]{0,3}
+"""
+assert %ParseState{
+         symbol_ids: symbol,
+         grammar_encoding: encoded
+       } = EBNF.encode(grammar)
+assert [1, 10, 2, 9, 9, 2, 9, 9, 2, 9, 9, 0, 7, 2, 9, 9, 2, 9, 9, 0, 4, 2, 9, 9, 0, 1, 0, 0, 0, 3, 1, 1, 0, 0, 65535] = encoded
+assert %{"root" => 0, "root_1" => 1} = symbol
+    end
+
+    test "tab{2}" do
+
+	grammar = """
+root ::= [\t]{2}
+"""
+assert %ParseState{
+         symbol_ids: symbol,
+         grammar_encoding: encoded
+       } = EBNF.encode(grammar)
+assert [1, 7, 2, 9, 9, 2, 9, 9, 0, 0, 0, 3, 1, 1, 0, 0, 65535] = encoded
+assert %{"root" => 0, "root_1" => 1} = symbol
+    end
+  end
+
+end