private void readLine()
{
Contract.Requires(!hasReadToEnd);
// 次の行のテキストを得る
++lineNumber;
string line = reader.ReadLine();
if (line == null)
{
hasReadToEnd = true;
return;
}
// トークンの種類ごとに判別してtokensに追加
foreach (Match match in regex.Matches(line))
{
Contract.Assume(match != null);
Contract.Assume(match.Groups["integer"] != null);
Contract.Assume(match.Groups["identifier"] != null);
Contract.Assume(match.Groups["operator"] != null);
Contract.Assume(match.Groups["string"] != null);
Token token = null;
if (match.Groups["integer"].Success)
{
token = new IntegerToken(lineNumber, Convert.ToInt32(match.Groups["integer"].Value, 10));
}
else if (match.Groups["identifier"].Success)
{
Contract.Assume(match.Groups["identifier"].Value.Length != 0);
token = new IdentifierToken(lineNumber, match.Groups["identifier"].Value);
}
else if (match.Groups["operator"].Success)
{
string key = match.Groups["operator"].Value;
Contract.Assume(operatorTypes.ContainsKey(key));
token = new OperatorToken(lineNumber, operatorTypes[key]);
}
else if (match.Groups["string"].Success)
{
token = new StringToken(lineNumber, match.Groups["string"].Value);
}
else
{
throw new NotImplementedException();
}
Contract.Assert(token != null);
tokens.AddLast(token);
}
}
/*
* statement : varStatement | ifStatement | forStatement | whileStatement | funcStatement | block | simple
* varStatement : varExpression ";"
* varExpression : "var" IDENTIFIER [ "=" expression ]
* ifStatement : "if" "(" expression ")" statement [ "else" statement ]
* forStatement : "for" "(" [ varExpression | expression ] ";" [ expression ] ";" [expression] ")" statement
* whileStatement : "while" "(" expression ")" statement
* funcStatement : "function" IDENTIFIER "(" [ arguments ] ")" block
* arguments : IDENTIFIER { "," IDENTIFIER }
* simple : ";" | expression ";"
* block : "{" { statement } "}"
* expression : literal { binary_op literal }
* literal : void | true | false | STRING | ["+"|"-"] NUMBER | factor
* factor : ( IDENTIFIER | "(" expression ")" ) [ funcCall ]
* funcCall : "(" [parameters] ")"
* parameters : expression { "," expression }
* binary_op : "==" | "!=" | "&&" | "||" | "<=" | ">=" | "=" | "+" | "-" | "*" | "/" | "%" | "<" | ">"
*/
private INode statement()
{
Contract.Ensures(Contract.Result <INode>() != null);
Token token = lexer.Peek(0);
if (token.Type == TokenType.Operator)
{
OperatorToken operatorToken = (OperatorToken)token;
if (operatorToken.Value != OperatorType.LeftBrace)
{
throw new SyntaxException(lexer.LineNumber);
}
return(block());
}
else if (token.Type == TokenType.Identifier)
{
var identifierToken = (IdentifierToken)token;
if (identifierToken.Value == "var")
{
return(varStatement());
}
if (identifierToken.Value == "if")
{
return(ifStatement());
}
if (identifierToken.Value == "for")
{
return(forStatement());
}
if (identifierToken.Value == "while")
{
return(whileStatement());
}
if (identifierToken.Value == "function")
{
return(funcStatement());
}
}
return(simple());
}