public void resume(string code)
{
this.code = code;
pos = 0;
lastnl = 0;
unit = null;
}
private ExpNode parseElmnt()
{
if (lex.Peek() == Token.NUM)
{
return(new NumExpNode(lex.Take()));
}
if (lex.Peek() == Token.ID)
{
LexUnit id = lex.Take();
if (lex.Peek() == Token.LPN)
{
lex.Take();
FncCallExpNode fnc = new FncCallExpNode();
fnc.ID = id;
fnc.args = parseArgs();
Match(Token.RPN, "expected ')' for valid function call");
return(fnc);
}
else
{
return(new IdExpNode(id));
}
}
if (lex.Peek() == Token.LPN)
{
lex.Take();
ExpNode exp = parseExp();
Match(Token.RPN, "expected ')' for valid expression");
return(exp);
}
throw new ParseException(ref lex.unit, "invalid in expression");
}
public void init(string code)
{
this.code = code;
pos = 0;
ln = 1;
lastnl = 0;
unit = null;
}
public LexUnit Take()
{
Peek();
var tmp = unit;
unit = null;
return(tmp);
}
static void error(LexUnit line, string msg)
{
errors.Add(string.Format("{0}: Symantic error : " + msg, line.line));
}
public StringExpNode(LexUnit unit)
{
STR = unit;
}
public IdExpNode(LexUnit id)
{
ID = id;
}
public NumExpNode(LexUnit num)
{
NUM = num;
}
public Token Peek()
{
if (unit != null)
{
return(unit.token);
}
unit = new LexUnit();
skipSpace();
if (isDigit())
{
start();
while (isDigit())
{
append();
}
if (isOneOf("."))
{
append();
while (isDigit())
{
append();
}
}
unit.token = Token.NUM;
return(Token.NUM);
}
if (isOneOf("()=+-*/^,\n"))
{
unit.token = (Token)code [pos];
start();
if (unit.token == Token.EOL)
{
unit.lexeme = "EOL";
}
return(unit.token);
}
if (isAlpha())
{
start();
while (isAlpha() || isDigit())
{
append();
}
if (unit.lexeme == "let")
{
unit.token = Token.LET;
}
else if (unit.lexeme == "fnc")
{
unit.token = Token.FNC;
}
else if (unit.lexeme == "print")
{
unit.token = Token.PRT;
}
else
{
unit.token = Token.ID;
}
return(unit.token);
}
if (!end() && code [pos] == '"')
{
pos++;
unit.lexeme = "";
while (code [pos] != '"' && code [pos] != '\n')
{
append();
}
if (code [pos] == '\n')
{
throw new Exception(string.Format("{0},{1}: Lexical error : Expected (\") to end a string", ln, pos - lastnl, code[pos]));
}
pos++;
unit.token = Token.STR;
return(unit.token);
}
if (end())
{
unit.token = Token.EOF;
unit.lexeme = "EOF";
return(unit.token);
}
throw new Exception(string.Format("{0},{1}: Lexical error : Unrecognized character '{2}'", ln, pos - lastnl, code[pos]));
}
public ParseException(ref LexUnit unexpected, string msg = null) :
base(string.Format("{0},{1}: Syntaxe error : unexpected '{2}'" + (msg != null?(", " + msg):""), unexpected.line, unexpected.colmn, unexpected.lexeme))
{
}
