Update parser.c

Author: AzliRynz

parser.c

@@ -53,10 +53,20 @@ static bool match(TokenType type) {
     return false;
 }
 
-static Expr* expression();
-static Stmt* statement();
-static Stmt* declaration();
-static Expr* unary();
+static Expr* expression() {
+    return binary();
+}
+
+static Expr* unary() {
+    if (match(TOKEN_MINUS) {
+        Expr* expr = malloc(sizeof(Expr));
+        expr->type = EXPR_UNARY;
+        expr->unary.op = parser.previous;
+        expr->unary.right = unary();
+        return expr;
+    }
+    return primary();
+}
 
 static Expr* binary() {
     Expr* expr = unary();
@@ -89,11 +99,35 @@ static Expr* binary() {
     }
 }
 
-static Stmt* parse_statement() {
+static Stmt* print_statement() {
+    Expr* expr = expression();
+    consume(TOKEN_SEMICOLON, "Expect ';' after value.");
+    
+    Stmt* stmt = malloc(sizeof(Stmt));
+    stmt->type = STMT_PRINT;
+    stmt->print.expr = expr;
+    return stmt;
+}
+
+static Stmt* expression_statement() {
+    Expr* expr = expression();
+    consume(TOKEN_SEMICOLON, "Expect ';' after expression.");
+    
+    Stmt* stmt = malloc(sizeof(Stmt));
+    stmt->type = STMT_EXPRESSION;
+    stmt->expression.expr = expr;
+    return stmt;
+}
+
+static Stmt* statement() {
     if (match(TOKEN_PRINT)) return print_statement();
     return expression_statement();
 }
 
+static Stmt* declaration() {
+    return statement();
+}
+
 void init_parser() {
     parser.had_error = false;
     parser.panic_mode = false;