From 6ae019698886c8191682475926ccbc669b01129c Mon Sep 17 00:00:00 2001
From: Web_dev_learner <shreelakshmisomayaji@gmail.com>
Date: Sat, 19 Oct 2024 06:20:16 +0530
Subject: [PATCH] implement if-else Conditional

---
 src/codegen.ml | 12 ++++++++++++
 src/expr.ml    | 12 ++++++++++++
 src/parser.mly | 12 ++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/src/codegen.ml b/src/codegen.ml
index 43dcb41..d60cfec 100755
--- a/src/codegen.ml
+++ b/src/codegen.ml
@@ -26,6 +26,12 @@ let rec eval_expr env e =
       val_to_print
   | Return expr ->
       eval_expr env expr
+  | IfElse (cond, then_stmt, else_stmt) ->  (* Evaluate if-else *)
+      let cond_val = eval_expr env cond in
+      if cond_val <> 0.0 then  (* Assuming non-zero values mean true *)
+        interpreter env then_stmt  (* Execute then block if true *)
+      else
+        interpreter env else_stmt  (* Execute else block if false *)    
   | _ -> raise (Error "Unsupported expression")
 
 let rec interpreter env stmts =
@@ -34,6 +40,12 @@ let rec interpreter env stmts =
   | stmt :: rest ->
       let _ = match stmt with
         | Expr e -> eval_expr env e
+        | IfElseStatement (cond, then_block, else_block) ->  (* Handle IfElseStatement *)
+            let cond_val = eval_expr env cond in
+            if cond_val <> 0.0 then
+              interpreter env then_block
+            else
+              interpreter env else_block
         | _ -> 0.0  (* Return 0.0 for unsupported statement types *)
       in
       interpreter env rest
diff --git a/src/expr.ml b/src/expr.ml
index 60d3ebf..d5d1f0b 100755
--- a/src/expr.ml
+++ b/src/expr.ml
@@ -1,3 +1,6 @@
+type expr =
+  | IfElse of expr * statement * statement  (* Add the IfElse type *)
+
 type util = 
   | Int of int
   | Double of float
@@ -16,6 +19,7 @@ type statement =
     | VariableDeclarationExpr of string * string * util
     | FunctionDeclaration of string * (string * string) list * statement list
     | ReturnStatement of util
+    | IfElseStatement of expr * block * block  (* Add IfElseStatement for handling blocks *)
 
 type block = statement list
 
@@ -49,6 +53,14 @@ and
         print_block_r body;
         Printf.printf "}\n";
     | ReturnStatement(e) -> print_expr (Return e)  
+    | IfElseStatement(cond, then_block, else_block) ->  (* Handle IfElseStatement *)
+      Printf.printf "if (";
+      print_expr cond;  (* Print the condition expression *)
+      Printf.printf ") {\n";
+      print_block_r then_block;  (* Print the 'then' block *)
+      Printf.printf "} else {\n";
+      print_block_r else_block;  (* Print the 'else' block *)
+      Printf.printf "}\n";
 and 
   print_block_r (b:block): unit = 
     match b with
diff --git a/src/parser.mly b/src/parser.mly
index 7d3c692..49ad79b 100755
--- a/src/parser.mly
+++ b/src/parser.mly
@@ -9,6 +9,7 @@
 %token LPAREN RPAREN LBRACE RBRACE
 %token EQUAL EQ NE LT LE GT GE AND OR CARET
 %token COMMA SEMICOLON RETURN FN WRITE
+%token IF ELSE
 %token EOF
 
 %type <string> ident
@@ -17,6 +18,7 @@
 %type <Expr.util list> call_args
 %type <Expr.block> program block_items block
 %type <Expr.statement> block_item var_decl func_decl
+%type <Expr.statement> if_else_stmt
 %type <string> comparison
 %start program
 
@@ -31,6 +33,7 @@ block_item: var_decl { $1 }
     | func_decl { $1 }
     | RETURN expr SEMICOLON { ReturnStatement($2) }
     | expr SEMICOLON { Expr($1) }
+    | if_else_stmt { $1 }  (* Added if-else support *)
     ;
 
 block: LBRACE block_items RBRACE { $2 }
@@ -89,5 +92,14 @@ comparison:
     | OR { "||" } 
     ;
 
+if_else_stmt: IF LPAREN expr RPAREN block ELSE block { 
+        IfElse ($3, $5, $7) 
+    }
+    | IF LPAREN expr RPAREN block { 
+        IfElse ($3, $5, [] )  (* No else block *)
+    }
+    ;
+
+
 %%