Added loop statements, FOR, WHILE and REPEAT

1 files changed, 139 insertions, 58 deletions

diff --git a/lib/Parser/Parser.cc b/lib/Parser/Parser.cc
index 998d50b..7a1af89 100644
--- a/lib/Parser/Parser.cc
+++ b/lib/Parser/Parser.cc
@@ -26,6 +26,22 @@ int Parser::GetTokPrecedence() {
     return TokPrec;
 }
 
+int Parser::getNextToken() {
+    return CurTok = Lex.gettok();
+}
+
+std::unique_ptr<ExprAST> Parser::ParseNumberExpr() {
+    auto Result = std::make_unique<NumberExprAST>(Lex.NumVal);
+    getNextToken();
+    return Result;
+}
+
+std::unique_ptr<ExprAST> Parser::ParseIdentifierExpr() {
+    std::string IdName = Lex.IdentifierStr;
+    getNextToken();
+    return std::make_unique<VariableExprAST>(IdName);
+}
+
 std::unique_ptr<ExprAST> Parser::ParseParenExpr() {
     getNextToken();
     auto V = ParseExpression();
@@ -52,9 +68,7 @@ std::unique_ptr<ExprAST> Parser::ParsePrimary() {
 std::unique_ptr<ExprAST> Parser::ParseBinOpRHS(int ExprPrec, std::unique_ptr<ExprAST> LHS) {
     while (true) {
         int TokPrec = GetTokPrecedence();
-
-        if (TokPrec < ExprPrec)
-            return LHS;
+        if (TokPrec < ExprPrec) return LHS;
 
         int BinOp = CurTok;
         getNextToken();
@@ -72,23 +86,6 @@ std::unique_ptr<ExprAST> Parser::ParseBinOpRHS(int ExprPrec, std::unique_ptr<Exp
     }
 }
 
-
-int Parser::getNextToken() {
-    return CurTok = Lex.gettok();
-}
-
-std::unique_ptr<ExprAST> Parser::ParseNumberExpr() {
-    auto Result = std::make_unique<NumberExprAST>(Lex.NumVal);
-    getNextToken();
-    return Result;
-}
-
-std::unique_ptr<ExprAST> Parser::ParseIdentifierExpr() {
-    std::string IdName = Lex.IdentifierStr;
-    getNextToken();
-    return std::make_unique<VariableExprAST>(IdName);
-}
-
 std::unique_ptr<ExprAST> Parser::ParseExpression() {
     auto LHS = ParsePrimary();
     if (!LHS) return nullptr;
@@ -97,7 +94,6 @@ std::unique_ptr<ExprAST> Parser::ParseExpression() {
 
 std::vector<std::unique_ptr<StmtAST>> Parser::Parse() {
     std::vector<std::unique_ptr<StmtAST>> Statements;
-
     while (CurTok != tok_eof) {
         if (auto Stmt = ParseStatement()) {
             Statements.push_back(std::move(Stmt));
@@ -108,10 +104,8 @@ std::vector<std::unique_ptr<StmtAST>> Parser::Parse() {
     return Statements;
 }
 
-
 std::unique_ptr<StmtAST> Parser::ParseIfStmt() {
     getNextToken();
-
     auto Cond = ParseExpression();
     if (!Cond) return nullptr;
 
@@ -121,7 +115,6 @@ std::unique_ptr<StmtAST> Parser::ParseIfStmt() {
     }
     getNextToken();
 
-
     std::vector<std::unique_ptr<StmtAST>> ThenStmts;
     while (CurTok != tok_else && CurTok != tok_endif && CurTok != tok_eof) {
         auto Stmt = ParseStatement();
@@ -146,69 +139,157 @@ std::unique_ptr<StmtAST> Parser::ParseIfStmt() {
     return std::make_unique<IfStmtAST>(std::move(Cond), std::move(ThenStmts), std::move(ElseStmts));
 }
 
+std::unique_ptr<StmtAST> Parser::ParseWhileStmt() {
+    getNextToken();
+    auto Cond = ParseExpression();
+    if (!Cond) return nullptr;
+
+    if (CurTok != tok_do) {
+        fprintf(stderr, "Error: expected DO after WHILE condition\n");
+        return nullptr;
+    }
+    getNextToken();
+
+    std::vector<std::unique_ptr<StmtAST>> Body;
+    while (CurTok != tok_endwhile && CurTok != tok_eof) {
+        auto Stmt = ParseStatement();
+        if (Stmt) Body.push_back(std::move(Stmt));
+    }
+
+    if (CurTok != tok_endwhile) {
+        fprintf(stderr, "Error: expected ENDWHILE\n");
+        return nullptr;
+    }
+    getNextToken();
+
+    return std::make_unique<WhileStmtAST>(std::move(Cond), std::move(Body));
+}
+
+std::unique_ptr<StmtAST> Parser::ParseRepeatStmt() {
+    getNextToken();
+
+    std::vector<std::unique_ptr<StmtAST>> Body;
+    while (CurTok != tok_until && CurTok != tok_eof) {
+        auto Stmt = ParseStatement();
+        if (Stmt) Body.push_back(std::move(Stmt));
+    }
+
+    if (CurTok != tok_until) {
+        fprintf(stderr, "Error: expected UNTIL\n");
+        return nullptr;
+    }
+    getNextToken();
+
+    auto Cond = ParseExpression();
+    if (!Cond) return nullptr;
+
+    return std::make_unique<RepeatStmtAST>(std::move(Body), std::move(Cond));
+}
+
+std::unique_ptr<StmtAST> Parser::ParseForStmt() {
+    getNextToken();
+    if (CurTok != tok_identifier) {
+        fprintf(stderr, "Error: expected identifier after FOR\n");
+        return nullptr;
+    }
+    std::string VarName = Lex.IdentifierStr;
+    getNextToken();
+
+    if (CurTok != tok_assign) {
+        fprintf(stderr, "Error: expected '<-' in FOR loop\n");
+        return nullptr;
+    }
+    getNextToken();
+
+    auto Start = ParseExpression();
+    if (!Start) return nullptr;
+
+    if (CurTok != tok_to) {
+        fprintf(stderr, "Error: expected TO in FOR loop\n");
+        return nullptr;
+    }
+    getNextToken();
+
+    auto End = ParseExpression();
+    if (!End) return nullptr;
+
+    std::unique_ptr<ExprAST> Step = nullptr;
+    if (CurTok == tok_step) {
+        getNextToken();
+        Step = ParseExpression();
+    }
+
+    std::vector<std::unique_ptr<StmtAST>> Body;
+    while (CurTok != tok_next && CurTok != tok_eof) {
+        auto Stmt = ParseStatement();
+        if (Stmt) Body.push_back(std::move(Stmt));
+    }
+
+    if (CurTok != tok_next) {
+        fprintf(stderr, "Error: expected NEXT\n");
+        return nullptr;
+    }
+    getNextToken();
+    
+    if (CurTok != tok_identifier) {
+        fprintf(stderr, "Error: expected identifier after NEXT (e.g., NEXT %s)\n", VarName.c_str());
+        return nullptr;
+    }
+
+    if (Lex.IdentifierStr != VarName) {
+        fprintf(stderr, "Error: NEXT identifier '%s' does not match FOR variable '%s'\n", 
+                Lex.IdentifierStr.c_str(), VarName.c_str());
+        return nullptr;
+    }
+    getNextToken();
+
+    return std::make_unique<ForStmtAST>(VarName, std::move(Start), std::move(End), std::move(Step), std::move(Body));
+}
+
 std::unique_ptr<StmtAST> Parser::ParseStatement() {
-    // DECLARE
     if (CurTok == tok_declare) {
         getNextToken();
-        if (CurTok != tok_identifier) {
-            fprintf(stderr, "Error: expected identifier after DECLARE\n");
-            return nullptr;
-        }
+        if (CurTok != tok_identifier) return nullptr;
         std::string Name = Lex.IdentifierStr;
         getNextToken();
-        
-        if (CurTok != tok_colon) {
-            fprintf(stderr, "Error: expected ':' after identifier\n");
-            return nullptr;
-        }
+        if (CurTok != tok_colon) return nullptr;
         getNextToken();
-
-        if (CurTok != tok_integer_kw) {
-            fprintf(stderr, "Error: expected INTEGER type\n");
-            return nullptr;
-        }
+        if (CurTok != tok_integer_kw) return nullptr;
         getNextToken();
         return std::make_unique<DeclareStmtAST>(Name);
     }
-    
-    // ASSIGNMENT (x <- expr)
     else if (CurTok == tok_identifier) {
         std::string Name = Lex.IdentifierStr;
-        getNextToken(); // eat Name
-
-        if (CurTok != tok_assign) {
-            fprintf(stderr, "Error: expected '<-' for assignment\n");
-            return nullptr;
-        }
         getNextToken();
-
+        if (CurTok != tok_assign) return nullptr;
+        getNextToken();
         auto Expr = ParseExpression();
         return std::make_unique<AssignStmtAST>(Name, std::move(Expr));
     }
-    
-    // INPUT
     else if (CurTok == tok_input) {
         getNextToken();
-        if (CurTok != tok_identifier) {
-            fprintf(stderr, "Error: expected identifier after INPUT\n");
-            return nullptr;
-        }
+        if (CurTok != tok_identifier) return nullptr;
         std::string Name = Lex.IdentifierStr;
         getNextToken();
         return std::make_unique<InputStmtAST>(Name);
     }
-    
-    // OUTPUT
     else if (CurTok == tok_output) {
         getNextToken();
         auto Expr = ParseExpression();
         return std::make_unique<OutputStmtAST>(std::move(Expr));
     }
-    
-    // IF
     else if (CurTok == tok_if) {
         return ParseIfStmt();
     }
+    else if (CurTok == tok_while) {
+        return ParseWhileStmt();
+    }
+    else if (CurTok == tok_repeat) {
+        return ParseRepeatStmt();
+    }
+    else if (CurTok == tok_for) {
+        return ParseForStmt();
+    }
 
     return nullptr;
 }