diff --git a/examples/arithmetics/arithmetic.tp2.json b/examples/arithmetics/arithmetic.tp2.json
deleted file mode 100644
index 42a8420..0000000
--- a/examples/arithmetics/arithmetic.tp2.json
+++ /dev/null
@@ -1,101 +0,0 @@
-{
-	"version": "2",
-	"lexer_rules": [
-		{
-			"pattern": " |\\t|\\n",
-			"pass": false,
-			"name": null
-		},
-		{
-			"pattern": "[0-9]+",
-			"pass": true,
-			"name": "[const]"
-		},
-		{
-			"pattern": "\\+",
-			"pass": false,
-			"name": "[plus]"
-		},
-		{
-			"pattern": "-",
-			"pass": false,
-			"name": "[minus]"
-		},
-		{
-			"pattern": "\\*",
-			"pass": false,
-			"name": "[times]"
-		},
-		{
-			"pattern": "/",
-			"pass": false,
-			"name": "[divided]"
-		},
-		{
-			"pattern": "\\(",
-			"pass": false,
-			"name": "[open]"
-		},
-		{
-			"pattern": "\\)|",
-			"pass": false,
-			"name": "[close]"
-		}
-	],
-	"parser_rules": [
-		{
-			"label": "{constant}",
-			"premise": "<expression>",
-			"conclusion": [
-				{"type": "terminal", "parameters": {"id": "[const]"}}
-			]
-		},
-		{
-			"label": "{product}",
-			"premise": "<expression>",
-			"conclusion": [
-				{"type": "variable", "parameters": {"id": "<expression>"}},
-				{"type": "terminal", "parameters": {"id": "[times]"}},
-				{"type": "variable", "parameters": {"id": "<expression>"}}
-			]
-		},
-		{
-			"label": "{quotient}",
-			"premise": "<expression>",
-			"conclusion": [
-				{"type": "variable", "parameters": {"id": "<expression>"}},
-				{"type": "terminal", "parameters": {"id": "[divided]"}},
-				{"type": "variable", "parameters": {"id": "<expression>"}}
-			]
-		},
-		{
-			"label": "{sum}",
-			"premise": "<expression>",
-			"conclusion": [
-				{"type": "variable", "parameters": {"id": "<expression>"}},
-				{"type": "terminal", "parameters": {"id": "[plus]"}},
-				{"type": "variable", "parameters": {"id": "<expression>"}}
-			]
-		},
-		{
-			"label": "{difference}",
-			"premise": "<expression>",
-			"conclusion": [
-				{"type": "variable", "parameters": {"id": "<expression>"}},
-				{"type": "terminal", "parameters": {"id": "[minus]"}},
-				{"type": "variable", "parameters": {"id": "<expression>"}}
-			]
-		},
-		{
-			"label": "{priorised}",
-			"premise": "<expression>",
-			"conclusion": [
-				{"type": "terminal", "parameters": {"id": "[open]"}},
-				{"type": "variable", "parameters": {"id": "<expression>"}},
-				{"type": "terminal", "parameters": {"id": "[close]"}}
-			]
-		}
-	],
-	"parser_start": "<expression>"
-}
-
diff --git a/examples/arithmetics/arithmetics.tp2 b/examples/arithmetics/arithmetics.tp2
new file mode 100644
index 0000000..1cd74eb
--- /dev/null
+++ b/examples/arithmetics/arithmetics.tp2
@@ -0,0 +1,19 @@
+@1
+
+[]        : " |\t|\n"
+[const]   : "[0-9]+" : ~
+[plus]    : "\+"
+[minus]   : "-"
+[times]   : "\*"
+[divided] : "/"
+[open]    : "\("
+[close]   : "\)"
+
+{constant}   : <expression> : [const]
+{product}    : <expression> : <expression> [times] <expression>
+{quotient}   : <expression> : <expression> [divided] <expression>
+{sum}        : <expression> : <expression> [plus] <expression>
+{difference} : <expression> : <expression> [minus] <expression>
+{priorised}  : <expression> : [open] <expression> [close]
+
+<expression>
diff --git a/examples/arithmetics/eval b/examples/arithmetics/eval
index 25c82c0..480ab69 100755
--- a/examples/arithmetics/eval
+++ b/examples/arithmetics/eval
@@ -6,17 +6,17 @@ import json as _json
 
 def evaluate(node):
 	# _sys.stderr.write("eval: %s\n" % _json.dumps(node))
-	if (node["label"] == "{constant}"):
+	if (node["label"] == "constant"):
 		return int(node["value"][0]["data"]["value"])
-	elif (node["label"] == "{sum}"):
+	elif (node["label"] == "sum"):
 		return (evaluate(node["children"][0]) + evaluate(node["children"][1]))
-	elif (node["label"] == "{difference}"):
+	elif (node["label"] == "difference"):
 		return (evaluate(node["children"][0]) - evaluate(node["children"][1]))
-	elif (node["label"] == "{product}"):
+	elif (node["label"] == "product"):
 		return (evaluate(node["children"][0]) * evaluate(node["children"][1]))
-	elif (node["label"] == "{quotient}"):
+	elif (node["label"] == "quotient"):
 		return (evaluate(node["children"][0]) / evaluate(node["children"][1]))
-	elif (node["label"] == "{priorised}"):
+	elif (node["label"] == "priorised"):
 		return evaluate(node["children"][0])
 	else:
 		raise ValueError("unhandled label: " + node["label"])
@@ -26,7 +26,7 @@ def main():
 	content = _sys.stdin.read()
 	node = _json.loads(content)
 	value = evaluate(node)
-	_sys.stdout.write(str(value) + "\n")
+	_sys.stdout.write(_json.dumps(value) + "\n")
 	
 
 main()
diff --git a/examples/arithmetics/readme.md b/examples/arithmetics/readme.md
new file mode 100644
index 0000000..452d241
--- /dev/null
+++ b/examples/arithmetics/readme.md
@@ -0,0 +1,5 @@
+## Usage
+
+- `cat examples/arithmetics/arithmetics.tp2 | tools/conv > /tmp/arithmetics.tp2.json`
+- `echo '2+3' | build/type2 /tmp/arithmetics.tp2.json`
+- `echo '(2+3)*5' | build/type2 /tmp/arithmetics.tp2.json | examples/arithmetics/eval`