diff --git a/tools/convert b/tools/convert
new file mode 100755
index 0000000..572f411
--- /dev/null
+++ b/tools/convert
@@ -0,0 +1,167 @@
+#!/usr/bin/env python3
+
+import sys as _sys
+import re as _re
+import json as _json
+
+
+def coin(template, arguments):
+	result = template
+	for (key, value, ) in arguments.items():
+		result = result.replace("{{%s}}" % key, value)
+	return result
+	
+
+def convert_symbol(symbol):
+	if (symbol.startswith("<")):
+		return {"type": "variable", "parameters": {"id": symbol[1:-1]}}
+	elif (symbol.startswith("[")):
+		return {"type": "terminal", "parameters": {"id": symbol[1:-1]}}
+	elif (symbol.startswith("{")):
+		return {"type": "label", "parameters": {"id": symbol[1:-1]}}
+	else:
+		raise ValueError("unknown symbol: %s" % symbol)
+	
+
+def extract_name(symbol, type_):
+	conversion = convert_symbol(symbol)
+	if (not (conversion["type"] == type_)):
+		raise ValueError("type mismatch")
+	else:
+		name = conversion["parameters"]["id"]
+		return (None if (name == "") else name)
+	
+
+
+def main():
+	pattern_name = "[0-9a-zA-Z_-]*"
+	pattern_terminal = coin("\[{{pattern_name}}\]", {"pattern_name": pattern_name})
+	pattern_variable = coin("<{{pattern_name}}>", {"pattern_name": pattern_name})
+	pattern_label = coin("\{{{pattern_name}}\}", {"pattern_name": pattern_name})
+	
+	rules = [
+		# version
+		{
+			"pattern": coin(
+				"@{{space}}(.+)",
+				{
+					"space": "\s*",
+				}
+			),
+			"action": lambda state, matching: {
+				"version": matching.group(1),
+				"specification": state["specification"],
+			},
+		},
+		# lexer_rule
+		{
+			"pattern": coin(
+				"{{space}}({{pattern_terminal}}){{space}}:{{space}}\"(.*)\"(?:{{space}}:{{space}}(\S+){{space}})?",
+				{
+					"space": "\s*",
+					"pattern_terminal": pattern_terminal,
+				}
+			),
+			"action": lambda state, matching: {
+				"version": state["version"],
+				"specification": {
+					"version": state["specification"]["version"],
+					"lexer_rules": (
+						state["specification"]["lexer_rules"]
+						+
+						[{
+							"pattern": matching.group(2),
+							"name": extract_name(matching.group(1), "terminal"),
+							"pass": (len(matching.groups()) >= 3),
+						}]
+					),
+					"parser_rules": state["specification"]["parser_rules"],
+					"parser_start": state["specification"]["parser_start"],
+				}
+			}
+		},
+		# parser_rule
+		{
+			"pattern": coin(
+				"({{pattern_label}}){{space}}:{{space}}({{pattern_variable}}){{space}}:(.*)",
+				{
+					"space": "\s*",
+					"pattern_variable": pattern_variable,
+					"pattern_label": pattern_label,
+				}
+			),
+			"action": lambda state, matching: {
+				"version": state["version"],
+				"specification": {
+					"version": state["specification"]["version"],
+					"lexer_rules": state["specification"]["lexer_rules"],
+					"parser_rules": (
+						state["specification"]["parser_rules"]
+						+
+						[{
+							"label": extract_name(matching.group(1), "label"),
+							"premise": extract_name(matching.group(2), "variable"),
+							"conclusion": list(map(
+								convert_symbol,
+								_re.findall(
+									coin(
+										"{{pattern_terminal}}|{{pattern_variable}}",
+										{
+											"pattern_terminal": pattern_terminal,
+											"pattern_variable": pattern_variable,
+										}
+									),
+									matching.group(3)
+								)
+							)),
+						}]
+					),
+					"parser_start": state["specification"]["parser_start"],
+				}
+			}
+		},
+		# parser_start
+		{
+			"pattern": coin(
+				"({{pattern_variable}})",
+				{
+					"space": "\s*",
+					"pattern_variable": pattern_variable,
+				}
+			),
+			"action": lambda state, matching: {
+				"version": state["version"],
+				"specification": {
+					"version": state["specification"]["version"],
+					"lexer_rules": state["specification"]["lexer_rules"],
+					"parser_rules": state["specification"]["parser_rules"],
+					"parser_start": extract_name(matching.group(1), "variable"),
+				}
+			}
+		},
+		# empty
+		{
+			"pattern": ".*",
+			"action": lambda state, matching: state,
+		},
+	]
+	
+	state = {
+		"version": "1",
+		"specification": {
+			"version": "2",
+			"lexer_rules": [],
+			"parser_rules": [],
+			"parser_start": None,
+		},
+	}
+	content = _sys.stdin.read()
+	for line in content.split("\n"):
+		for rule in rules:
+			matching = _re.match("^%s$" % rule["pattern"], line)
+			if (not (matching is None)):
+				state = rule["action"](state, matching)
+				break
+	_sys.stdout.write(_json.dumps(state["specification"], indent = "\t"))
+
+main()