public static LinkedListNode <Lexeme> TryParse(LinkedListNode <Lexeme> lexemes, out WhileLoop resultNode) { resultNode = null; if (lexemes.Value.Type != LT.KW_IF) { return(lexemes); } var nextLexeme = lexemes.Next; if (nextLexeme.Value.Type != LT.OP_PAREN_O) { throw new Exception($"Missing if condition at {nextLexeme.Value.File}:{nextLexeme.Value.Line}"); } Lexeme token = nextLexeme.Value; nextLexeme = BinaryExpr.TryParseExpr(nextLexeme, out Expr expr); if (expr == null) { throw new Exception($"Cannot parse if condition at {nextLexeme.Value.File}:{nextLexeme.Value.Line}"); } if (nextLexeme.Value.Type != LT.OP_PAREN_C) { throw new Exception($"Missing closing parenthesis for if condition at {nextLexeme.Value.File}:{nextLexeme.Value.Line}"); } nextLexeme = nextLexeme.Next; Stmt stmt; List <Stmt> stmts = new List <Stmt>(); if (nextLexeme.Value.Type == LT.OP_BRACE_O) { // block body nextLexeme = nextLexeme.Next; nextLexeme = Stmt.TryParse(nextLexeme, out stmt); while (stmt != null) { stmts.Add(stmt); nextLexeme = Stmt.TryParse(nextLexeme, out stmt); } if (nextLexeme.Value.Type != LT.OP_BRACE_C) { throw new Exception($"Missing closing bracket for while loop body at {nextLexeme.Value.File}:{nextLexeme.Value.Line}"); } nextLexeme = nextLexeme.Next; } else { // single statement body nextLexeme = Stmt.TryParse(nextLexeme, out stmt); if (stmt == null) { throw new Exception($"Missing while loop body at {nextLexeme.Value.File}:{nextLexeme.Value.Line}"); } stmts.Add(stmt); } resultNode = new WhileLoop { Condition = expr, Body = new BlockBody(stmts), Token = token }; return(nextLexeme); }
public static LinkedListNode <Lexeme> TryParse(LinkedListNode <Lexeme> lexemes, out Stmt resultNode) { resultNode = null; if (lexemes.Value.Type == LT.OP_SC) { resultNode = new BlankStmt(); return(lexemes.Next); } var nextLexeme = IfStmt.TryParse(lexemes, out IfStmt sif); if (sif != null) { resultNode = sif; return(nextLexeme); } nextLexeme = TryParseStruct(lexemes, out Stmt stmt); if (stmt != null) { resultNode = stmt; return(nextLexeme); } nextLexeme = FnCall.TryParse(lexemes, out FnCall fnc); if (fnc != null) { if (nextLexeme.Value.Type == LT.OP_SC) { resultNode = new ExprStmt <FnCall>(fnc); return(nextLexeme.Next); } } nextLexeme = ForLoop.TryParse(lexemes, out ForLoop fl); if (fl != null) { resultNode = fl; return(nextLexeme); } nextLexeme = WhileLoop.TryParse(lexemes, out WhileLoop wl); if (wl != null) { resultNode = wl; return(nextLexeme); } nextLexeme = AssignStmt.TryParse(lexemes, out AssignStmt sa); if (sa != null) { resultNode = sa; return(nextLexeme); } nextLexeme = ReturnStmt.TryParse(lexemes, out ReturnStmt sr); if (sr != null) { resultNode = sr; return(nextLexeme); } if (lexemes.Value.Type == LT.KW_BREAK) { if (lexemes.Next.Value.Type != LT.OP_SC) { throw new Exception($"Missing semicolon after break keyword at {lexemes.Value.File}:{lexemes.Value.Line}"); } resultNode = new BreakStmt { Token = lexemes.Value }; return(lexemes.Next.Next); } if (lexemes.Value.Type == LT.KW_CONT) { if (lexemes.Next.Value.Type != LT.OP_SC) { throw new Exception($"Missing semicolon after continue keyword at {lexemes.Value.File}:{lexemes.Value.Line}"); } resultNode = new ContinueStmt { Token = lexemes.Value }; return(lexemes.Next.Next); } return(lexemes); }