SyntaxTree ParseMainExp()
{
SyntaxTree exp;
switch (LookAhead().m_type)
{
case (int)TokenType.NIL:
case (int)TokenType.FALSE:
case (int)TokenType.TRUE:
case (int)TokenType.NUMBER:
case (int)TokenType.STRING:
case (int)TokenType.DOTS:
exp = new Terminator(NextToken());
break;
case (int)TokenType.FUNCTION:
exp = ParseFunctionDef();
break;
case (int)TokenType.NAME:
case (int)'(':
exp = ParsePrefixExp();
break;
case (int)'{':
exp = ParseTableConstructor();
break;
// unop exp priority is 90 less then ^
case (int)'-':
case (int)'#':
case (int)TokenType.NOT:
var unexp = new UnaryExpression(LookAhead().m_line);
unexp.op = NextToken();
unexp.exp = ParseExp(90);
exp = unexp;
break;
default:
throw NewParserException("unexpect token for main exp", _look_ahead);
}
return(exp);
}
SyntaxTree ParsePrefixExp()
{
NextToken();
Debug.Assert(_current.m_type == (int)TokenType.NAME ||
_current.m_type == (int)'(');
SyntaxTree exp;
if (_current.m_type == (int)'(')
{
exp = ParseExp();
if (NextToken().m_type != (int)')')
{
throw NewParserException("expect ')'", _current);
}
}
else
{
exp = new Terminator(_current);
}
// table index or func call
for (;;)
{
if (LookAhead().m_type == (int)'[' ||
LookAhead().m_type == (int)'.')
{
exp = ParseTableAccessor(exp);
}
else if (LookAhead().m_type == (int)'(' ||
LookAhead().m_type == (int)'{')
{
exp = ParseFunctionCall(exp);
}
else
{
break;
}
}
return(exp);
}