static Expr ParseExpr()
{
Expr ret = null;
Token t = tokens.GetToken();
if (tokens.Peek().TokenName == Lexer.Tokens.LeftParan)
{
string ident = "";
if (t.TokenName == Lexer.Tokens.Ident)
{
ident = t.TokenValue.ToString();
}
tokens.pos++;
if (tokens.Peek().TokenName == Lexer.Tokens.RightParan)
{
ret = new CallExpr(ident, new List <Expr>());
}
else
{
ret = new CallExpr(ident, ParseCallArgs());
}
}
else if (t.TokenName == Lexer.Tokens.IntLiteral)
{
IntLiteral i = new IntLiteral(Convert.ToInt32(t.TokenValue.ToString()));
ret = i;
}
else if (t.TokenName == Lexer.Tokens.StringLiteral)
{
StringLiteral s = new StringLiteral(t.TokenValue.ToString());
ret = s;
}
else if (t.TokenName == Lexer.Tokens.Ident)
{
string ident = t.TokenValue.ToString();
Ident i = new Ident(ident);
ret = i;
}
else if (t.TokenName == Lexer.Tokens.LeftParan)
{
Expr e = ParseExpr();
if (tokens.Peek().TokenName == Lexer.Tokens.RightParan)
{
tokens.pos++;
}
ParanExpr p = new ParanExpr(e);
if (tokens.Peek().TokenName == Lexer.Tokens.Add)
{
tokens.pos++;
Expr expr = ParseExpr();
ret = new MathExpr(p, Symbol.add, expr);
}
else if (tokens.Peek().TokenName == Lexer.Tokens.Sub)
{
tokens.pos++;
Expr expr = ParseExpr();
ret = new MathExpr(p, Symbol.sub, expr);
}
else if (tokens.Peek().TokenName == Lexer.Tokens.Mul)
{
tokens.pos++;
Expr expr = ParseExpr();
ret = new MathExpr(p, Symbol.mul, expr);
}
else if (tokens.Peek().TokenName == Lexer.Tokens.Div)
{
tokens.pos++;
Expr expr = ParseExpr();
ret = new MathExpr(p, Symbol.div, expr);
}
else
{
ret = p;
}
}
if (tokens.Peek().TokenName == Lexer.Tokens.Add || tokens.Peek().TokenName == Lexer.Tokens.Sub || tokens.Peek().TokenName == Lexer.Tokens.Mul || tokens.Peek().TokenName == Lexer.Tokens.Div)
{
Expr lexpr = ret;
Symbol op = 0;
if (tokens.Peek().TokenName == Lexer.Tokens.Add)
{
op = Symbol.add;
}
else if (tokens.Peek().TokenName == Lexer.Tokens.Sub)
{
op = Symbol.sub;
}
else if (tokens.Peek().TokenName == Lexer.Tokens.Mul)
{
op = Symbol.mul;
}
else if (tokens.Peek().TokenName == Lexer.Tokens.Div)
{
op = Symbol.div;
}
tokens.pos++;
Expr rexpr = ParseExpr();
ret = new MathExpr(lexpr, op, rexpr);
}
return(ret);
}
public Parser(TokenList t)
{
tokens = t;
currentBlock = null;
blockstack = new Stack <Block>();
Token tok = null;
tree = new List <Stmt>();
running = true;
while (running)
{
try
{
tok = tokens.GetToken();
}
catch { }
if (tok.TokenName == Lexer.Tokens.Import)
{
Program.imports.Add(ParseImport());
}
else if (tok.TokenName == Lexer.Tokens.Function)
{
Func func = ParseFunc();
if (currentBlock == null)
{
currentBlock = func;
}
else
{
currentBlock.AddStmt(new Return(null));
tree.Add(currentBlock);
currentBlock = func;
}
}
else if (tok.TokenName == Lexer.Tokens.If)
{
IfBlock ifblock = ParseIf();
if (currentBlock != null)
{
blockstack.Push(currentBlock);
currentBlock = ifblock;
}
}
else if (tok.TokenName == Lexer.Tokens.ElseIf)
{
ElseIfBlock elseifblock = ParseElseIf();
if (currentBlock != null)
{
blockstack.Push(currentBlock);
currentBlock = elseifblock;
}
}
else if (tok.TokenName == Lexer.Tokens.Else)
{
if (currentBlock != null)
{
blockstack.Push(currentBlock);
currentBlock = new ElseBlock();
}
}
else if (tok.TokenName == Lexer.Tokens.Repeat)
{
if (currentBlock != null)
{
blockstack.Push(currentBlock);
currentBlock = new RepeatBlock();
}
}
else if (tok.TokenName == Lexer.Tokens.Ident)
{
if (tokens.Peek().TokenName == Lexer.Tokens.Equal)
{
tokens.pos--;
Assign a = ParseAssign();
currentBlock.AddStmt(a);
}
else if (tokens.Peek().TokenName == Lexer.Tokens.LeftParan)
{
tokens.pos--;
Call c = ParseCall();
currentBlock.AddStmt(c);
}
}
else if (tok.TokenName == Lexer.Tokens.Return)
{
Return r = ParseReturn();
currentBlock.AddStmt(r);
}
else if (tok.TokenName == Lexer.Tokens.RightBrace)
{
if (currentBlock is Func)
{
currentBlock.AddStmt(new Return(null));
tree.Add(currentBlock);
currentBlock = null;
}
else if (currentBlock is IfBlock || currentBlock is ElseIfBlock || currentBlock is ElseBlock)
{
currentBlock.AddStmt(new EndIf());
Block block = currentBlock;
if (blockstack.Count > 0)
{
currentBlock = blockstack.Pop();
currentBlock.AddStmt(block);
}
}
else if (currentBlock is RepeatBlock)
{
Block block = currentBlock;
if (blockstack.Count > 0)
{
currentBlock = blockstack.Pop();
currentBlock.AddStmt(block);
}
}
}
else if (tok.TokenName == Lexer.Tokens.EOF)
{
tree.Add(currentBlock);
running = false;
}
}
}