while

src/ast/statements.hpp

@@ -191,3 +191,25 @@ struct Module : Node
         return oss.str();
     }
 };
+
+struct While : Stmt
+{
+    ptr<Expr> condition;
+    std::vector<ptr<Stmt>> body;
+
+    While(ptr<Expr> cond, std::vector<ptr<Stmt>> b)
+        : condition(std::move(cond)), body(std::move(b)) {}
+
+    std::string dump(int indent = 0) const override
+    {
+        std::ostringstream oss;
+        oss << indent_str(indent) << "While\n";
+        oss << condition->dump(indent + 1);
+        for (const auto &stmt : body)
+        {
+            oss << "\n"
+                << stmt->dump(indent + 1);
+        }
+        return oss.str();
+    }
+};

src/lexer.l

@@ -49,6 +49,7 @@ pass                    { return yy::parser::token::TOK_KW_PASS; }
 else                    { return yy::parser::token::TOK_KW_ELSE; }
 elif                    { return yy::parser::token::TOK_KW_ELIF; }
 class                   { return yy::parser::token::TOK_KW_CLASS; }
+while                   { return yy::parser::token::TOK_KW_WHILE; }
 
 \=\=                    { return yy::parser::token::TOK_EQ; }
 \!\=                    { return yy::parser::token::TOK_NE; }

src/parser.y

@@ -32,7 +32,7 @@
 %left KW_OR
 %left KW_AND
 %right KW_NOT          // unary logical NOT
-%token KW_DEF KW_IF KW_RETURN KW_FOR KW_IN KW_PASS KW_ELSE KW_ELIF KW_CLASS
+%token KW_DEF KW_IF KW_RETURN KW_FOR KW_IN KW_PASS KW_ELSE KW_ELIF KW_CLASS KW_WHILE
 
 %token L_PAREN R_PAREN L_BRACKET R_BRACKET L_BRACE R_BRACE
 %token DOT COLON SEMICOLON COMMA
@@ -94,6 +94,9 @@ stmt:
     | KW_RETURN expr NEWLINE { 
         $$ = std::make_unique<Return>(std::move($2));
     }
+    | KW_WHILE expr COLON NEWLINE INDENT stmt_list DEDENT {
+        $$ = std::make_unique<While>(std::move($2), std::move($6));
+    }
     ;
 
 expr:
@@ -102,6 +105,7 @@ expr:
     | STRING              { $$ = std::make_unique<String>($1); }
     | expr PLUS expr      { $$ = std::make_unique<BinOp>( BinaryOperator(BinaryOperator::ADD), std::move($1), std::move($3)); }
     | expr MULTIPLY expr  { $$ = std::make_unique<BinOp>( BinaryOperator(BinaryOperator::MUL), std::move($1), std::move($3)); }
+    | expr MINUS expr     { $$ = std::make_unique<BinOp>( BinaryOperator(BinaryOperator::SUB), std::move($1), std::move($3)); }
     | expr LT expr        { $$ = std::make_unique<BinOp>( BinaryOperator(BinaryOperator::LT) , std::move($1), std::move($3)); }
     | expr KW_AND expr    { $$ = std::make_unique<BinOp>( BinaryOperator(BinaryOperator::AND) , std::move($1), std::move($3)); }
     | expr KW_OR expr     { $$ = std::make_unique<BinOp>( BinaryOperator(BinaryOperator::OR) , std::move($1), std::move($3)); }

test/parser/25.in

@@ -1,3 +1,2 @@
 while x:
     x = x - 1
-

test/parser/25.out

@@ -6,4 +6,3 @@ Module
       BinOp(-)
         Identifier(x)
         Number(1)
-