2 files changed, 168 insertions, 10 deletions

diff --git a/lib/Parser/Parser.cc b/lib/Parser/Parser.cc
index b9396ce..563dd9b 100644
--- a/lib/Parser/Parser.cc
+++ b/lib/Parser/Parser.cc
@@ -1,4 +1,5 @@
 #include "cps/Parser.h"
+#include "cps/FunctionAST.h"
 
 using namespace cps;
 
@@ -40,24 +41,40 @@ std::unique_ptr<ExprAST> Parser::ParseIdentifierExpr() {
     std::string IdName = Lex.IdentifierStr;
     int Line = Lex.getLine();
     getNextToken();
+
+    if (CurTok == '(') {
+        getNextToken();
+        std::vector<std::unique_ptr<ExprAST>> Args;
+        if (CurTok != ')') {
+            while (true) {
+                if (auto Arg = ParseExpression())
+                    Args.push_back(std::move(Arg));
+                else
+                    return nullptr;
+
+                if (CurTok == ')') break;
+
+                if (CurTok != ',') {
+                    fprintf(stderr, "Error: Expected ')' or ',' in function call.\n");
+                    return nullptr;
+                }
+                getNextToken();
+            }
+        }
+        getNextToken();
+        return std::make_unique<CallExprAST>(IdName, std::move(Args));
+    }
     
     if (CurTok == '[') {
         getNextToken();
         std::vector<std::unique_ptr<ExprAST>> Indices;
-        
         while (true) {
             auto Exp = ParseExpression();
             if (!Exp) return nullptr;
             Indices.push_back(std::move(Exp));
-            
-            if (CurTok == ']') {
-                break;
-            }
-            if (CurTok == ',') {
-                getNextToken();
-                continue;
-            }
-            fprintf(stderr, "Error: Expected ',' or ']' in array index\n");
+            if (CurTok == ']') break;
+            if (CurTok == ',') { getNextToken(); continue; }
+            fprintf(stderr, "Error: Expected ',' or ']'\n");
             return nullptr;
         }
         getNextToken(); 
@@ -407,6 +424,18 @@ std::unique_ptr<StmtAST> Parser::ParseStatement() {
     else if (CurTok == tok_for) {
         return ParseForStmt();
     }
+    else if (CurTok == tok_function) {
+        return ParseFunction();
+    }
+    else if (CurTok == tok_procedure) {
+        return ParseProcedure();
+    }
+    else if (CurTok == tok_call) {
+        return ParseCallStmt();
+    }
+    else if (CurTok == tok_return) {
+        return ParseReturnStmt();
+    }
 
     return nullptr;
 }
diff --git a/lib/Parser/Parser_Function.cc b/lib/Parser/Parser_Function.cc
new file mode 100644
index 0000000..bdb4ee7
--- /dev/null
+++ b/lib/Parser/Parser_Function.cc
@@ -0,0 +1,129 @@
+#include "cps/Parser.h"
+#include "cps/FunctionAST.h"
+
+using namespace cps;
+
+std::vector<std::pair<std::string, std::string>> Parser::ParsePrototypeArgs() {
+    std::vector<std::pair<std::string, std::string>> Args;
+    if (CurTok != '(') return Args;
+    getNextToken();
+
+    while (CurTok != ')') {
+        if (CurTok == -1000 || CurTok == -1001) getNextToken();
+
+        if (CurTok != tok_identifier) {
+            fprintf(stderr, "Error: Expected argument name\n");
+            return Args;
+        }
+        std::string Name = Lex.IdentifierStr;
+        getNextToken();
+
+        if (CurTok != tok_colon) {
+            fprintf(stderr, "Error: Expected ':' after argument name\n");
+            return Args;
+        }
+        getNextToken();
+
+        std::string Type = "INTEGER";
+        if (CurTok == tok_integer_kw) {
+            getNextToken();
+        } else if (CurTok == tok_identifier) {
+            Type = Lex.IdentifierStr; 
+            getNextToken();
+        } else {
+             fprintf(stderr, "Error: Expected type (e.g. INTEGER) for argument '%s'\n", Name.c_str());
+             return Args;
+        }
+
+        Args.push_back({Name, Type});
+
+        if (CurTok == ')') break;
+        if (CurTok != ',') {
+            fprintf(stderr, "Error: Expected ',' or ')'\n");
+            return Args;
+        }
+        getNextToken();
+    }
+    getNextToken();
+    return Args;
+}
+
+
+std::unique_ptr<StmtAST> Parser::ParseFunction() {
+    getNextToken();
+    std::string Name = Lex.IdentifierStr;
+    getNextToken();
+
+    auto Args = ParsePrototypeArgs();
+
+    std::string RetType = "INTEGER";
+    if (CurTok == tok_returns) { 
+        getNextToken();
+        getNextToken();
+    }
+
+    auto Proto = std::make_unique<PrototypeAST>(Name, std::move(Args), RetType);
+
+    std::vector<std::unique_ptr<StmtAST>> Body;
+    while (CurTok != tok_endfunction && CurTok != tok_eof) {
+        auto Stmt = ParseStatement();
+        if (Stmt) Body.push_back(std::move(Stmt));
+        else if (CurTok != tok_eof && CurTok != tok_endfunction) getNextToken();
+    }
+    getNextToken();
+
+    return std::make_unique<FunctionDefAST>(std::move(Proto), std::move(Body));
+}
+
+std::unique_ptr<StmtAST> Parser::ParseProcedure() {
+    getNextToken();
+    std::string Name = Lex.IdentifierStr;
+    getNextToken();
+
+    auto Args = ParsePrototypeArgs();
+    auto Proto = std::make_unique<PrototypeAST>(Name, std::move(Args), "VOID");
+
+    std::vector<std::unique_ptr<StmtAST>> Body;
+    while (CurTok != tok_endprocedure && CurTok != tok_eof) {
+        auto Stmt = ParseStatement();
+        if (Stmt) Body.push_back(std::move(Stmt));
+        else if (CurTok != tok_eof && CurTok != tok_endprocedure) getNextToken();
+    }
+    getNextToken();
+
+    return std::make_unique<FunctionDefAST>(std::move(Proto), std::move(Body));
+}
+
+std::unique_ptr<StmtAST> Parser::ParseCallStmt() {
+    getNextToken();
+    std::string Callee = Lex.IdentifierStr;
+    getNextToken();
+
+    std::vector<std::unique_ptr<ExprAST>> Args;
+    if (CurTok == '(') {
+        getNextToken();
+        while (CurTok != ')') {
+            auto Arg = ParseExpression();
+            if (Arg) Args.push_back(std::move(Arg));
+            
+            if (CurTok == ')') break;
+            if (CurTok != ',') {
+                fprintf(stderr, "Error: Expected ',' or ')' in call\n");
+                return nullptr;
+            }
+            getNextToken();
+        }
+        getNextToken();
+    }
+    
+    return std::make_unique<CallStmtAST>(Callee, std::move(Args));
+}
+
+std::unique_ptr<StmtAST> Parser::ParseReturnStmt() {
+    getNextToken();
+    std::unique_ptr<ExprAST> Expr = nullptr;
+    if (CurTok != tok_endif && CurTok != tok_else && CurTok != tok_endfunction && CurTok != tok_endprocedure) {
+        Expr = ParseExpression();
+    }
+    return std::make_unique<ReturnStmtAST>(std::move(Expr));
+}