From 111620a649387bd914419e11566a648b2bec03fe Mon Sep 17 00:00:00 2001
From: Dr-Carlos <dr.steven.carlos@gmail.com>
Date: Sun, 18 Dec 2022 07:22:09 +1030
Subject: [PATCH] _d: determine address or range in _d

---
 shell/d.cpp | 30 ++++++++++--------------------
 1 file changed, 10 insertions(+), 20 deletions(-)

diff --git a/shell/d.cpp b/shell/d.cpp
index d688680..d892089 100644
--- a/shell/d.cpp
+++ b/shell/d.cpp
@@ -71,8 +71,7 @@ static void disassemble(Session &session, Disassembly &disasm,
 
 struct _d_args
 {
-    std::optional<uint32_t> address;
-    std::optional<Range> range;
+    std::variant<long, Range> location;
 };
 
 static _d_args parse_d(Session &session, Parser &parser)
@@ -82,32 +81,23 @@ static _d_args parse_d(Session &session, Parser &parser)
     if(!session.current_space)
         return {};
 
-    args.address = session.current_space->cursor;
-    args.range = {};
-
-    if(!parser.at_end()) {
-        auto v = parser.expr_or_range(session.current_space);
-
-        if(std::holds_alternative<long>(v))
-            args.address = std::get<long>(v);
-        else
-            args.range = std::get<Range>(v);
-    }
+    args.location = parser.at_end()
+                        ? session.current_space->cursor
+                        : parser.expr_or_range(session.current_space);
 
     parser.end();
     return args;
 }
 
-void _d(Session &session, std::optional<uint32_t> address_opt,
-    std::optional<Range> range_opt)
+void _d(Session &session, std::variant<long, Range> location)
 {
     if(!session.current_space)
         return;
     FxOS::Disassembly disasm(*session.current_space);
 
 
-    if(range_opt.has_value()) {
-        Range range = range_opt.value();
+    if(std::holds_alternative<Range>(location)) {
+        Range range = std::get<Range>(location);
         if(range.start & 1) {
             fmt::print("address 0x{:08x} is odd, starting at 0x{:08x}\n",
                 range.start, range.start + 1);
@@ -129,8 +119,8 @@ void _d(Session &session, std::optional<uint32_t> address_opt,
         disassemble(session, disasm,
             {"pcrel", /*"constprop",*/ "syscall", "print"}, -1);
     }
-    else if(address_opt.has_value()) {
-        uint32_t address = address_opt.value();
+    else {
+        uint32_t address = std::get<long>(location);
 
         if(address & 1) {
             fmt::print("address 0x{:08x} is odd, starting at 0x{:08x}\n",
@@ -151,7 +141,7 @@ static ShellCommand _d_cmd(
     "d",
     [](Session &s, Parser &p) {
         auto args = parse_d(s, p);
-        _d(s, args.address, args.range);
+        _d(s, args.location);
     },
     [](Session &s, Parser &p) { parse_d(s, p); }, "Disassemble", R"(
 d [<address|range>]