Add cancel buffer (to store cancelled operations.)

include/internal/buffer/types/generic.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include "../decl.h"
-#include "history.h"
+#include "readonly.h"
 #include "shard.h"
 
 namespace bed::internal::buffer {
@@ -25,7 +25,7 @@ struct GenericBuffer : ShardBuffer {
   ~GenericBuffer();
 
   void list_history(BEd &ctx);
-  HistoryBuffer *get_history(uint64_t version);
+  ReadonlyBuffer *get_history(uint64_t version);
   void snapshot(std::string action);
   bool undo(BEd &ctx);
   bool redo(BEd &ctx);

include/internal/buffer/types/readonly.h

@@ -4,36 +4,38 @@
 #include "shard.h"
 
 namespace bed::internal::buffer {
-struct HistoryBuffer : ShardBuffer {
-  HistoryBuffer(
+struct ReadonlyBuffer : ShardBuffer {
+  bool useless = true;
+
+  ReadonlyBuffer(
     std::string name, vase::Shard *root,
     const syntax::ParserSnapshot &snapshot
   ) : ShardBuffer(std::move(name), root, snapshot, Kind::History) {}
 
   bool waste() override {
-    return true;
+    return useless;
   }
   void load(BEd &, vase::Shard *) override {
-    throw ed_error("History buffers are read-only.");
+    throw ed_error("This buffer is read-only.");
   }
   void set_filename(std::filesystem::path) override {}
   std::filesystem::path filename() override {
     return {};
   }
   void substitute(BEd &, uint64_t, uint64_t, std::string &, std::string &, std::string &) override {
-    throw ed_error("History buffers are read-only.");
+    throw ed_error("This buffer is read-only.");
   }
   void join(BEd &, uint64_t, uint64_t) override {
-    throw ed_error("History buffers are read-only.");
+    throw ed_error("This buffer is read-only.");
   }
   void remove(BEd &, uint64_t, uint64_t) override {
-    throw ed_error("History buffers are read-only.");
+    throw ed_error("This buffer is read-only.");
   }
   void append(BEd &, vase::Shard *, uint64_t) override {
-    throw ed_error("History buffers are read-only.");
+    throw ed_error("This buffer is read-only.");
   }
   void replace(BEd &, vase::Shard *, uint64_t, uint64_t) override {
-    throw ed_error("History buffers are read-only.");
+    throw ed_error("This buffer is read-only.");
   }
 };
 } // namespace bed::internal::buffer

src/bed/run.cc

@@ -171,7 +171,14 @@ void BEd::handle(std::string_view cmd, bool eof) {
     if (!b) {
       text = a;
     } else {
-      internal::vase::Shard::release(a);
+      if (a) {
+        auto p = internal::syntax::make_parser(a, a->lines + 1, lang);
+        auto cancel_buf = new internal::buffer::ReadonlyBuffer("cancel", a, p);
+        internal::syntax::release(p);
+        buffers["cancel"] = cancel_buf;
+        cancel_buf->useless = false;
+        internal::vase::Shard::release(a);
+      }
       throw ed_error("Operation cancelled.");
     }
   }
@@ -194,13 +201,15 @@ void BEd::handle(std::string_view cmd, bool eof) {
 
 internal::buffer::Buffer &BEd::buffer(const std::string &name) {
   if (name.empty())
-    throw ed_error("can't have empty buffer name");
+    throw ed_error("Can't have empty buffer name");
   {
     auto it = buffers.find(name);
     if (it != buffers.end())
       return *it->second;
   }
   constexpr std::string_view prefix = "history/";
+  if (name == "cancel")
+    throw ed_error("Cancel buffer empty.");
   if (name.starts_with(prefix)) {
     std::string_view path{name};
     path.remove_prefix(prefix.size());

src/internal/buffer/generic.cc

@@ -72,21 +72,21 @@ void GenericBuffer::list_history(BEd &ctx) {
   }
 }
 
-HistoryBuffer *GenericBuffer::get_history(uint64_t version) {
+ReadonlyBuffer *GenericBuffer::get_history(uint64_t version) {
   uint64_t current = base_version + undo_stack.size();
   if (version < base_version)
     throw ed_error("History version has been pruned.");
   if (version < current) {
     auto &item = undo_stack[version - base_version];
-    return new HistoryBuffer(name, item.text, item.parse_state);
+    return new ReadonlyBuffer(name, item.text, item.parse_state);
   }
   if (version == current)
-    return new HistoryBuffer(name, root, parse);
+    return new ReadonlyBuffer(name, root, parse);
   uint64_t redo_offset = version - current - 1;
   if (redo_offset >= redo_stack.size())
     throw ed_error("No such history version.");
   auto &item = redo_stack[redo_stack.size() - 1 - redo_offset];
-  return new HistoryBuffer(name, item.text, item.parse_state);
+  return new ReadonlyBuffer(name, item.text, item.parse_state);
 }
 
 void GenericBuffer::snapshot(std::string action_) {

src/internal/parser/address.cc

@@ -188,6 +188,7 @@ void Parser::locator(AddressPromise &addr) {
     token(io::Token::AddressSymbol);
     advance();
     end_token();
+    token(io::Token::Number);
     addr.base = AddressPromise::Current{};
     uint16_t j = 0;
     uint64_t num = 0;

src/internal/ui/text_mode/text_mode.cc

@@ -272,7 +272,7 @@ std::pair<vase::Shard *, bool> TextMode::run_terminal() {
         cursor.col = byte_column(previous.line, wanted);
       } break;
       case io::KeyEvent::SpecialKey::DOWN: {
-        if (cursor.row + 1 >= vase->lines)
+        if (cursor.row >= vase->lines)
           break;
         vase::Iterator current(vase, cursor.row, Direction::Forward);
         if (!current.next())
@@ -294,7 +294,7 @@ std::pair<vase::Shard *, bool> TextMode::run_terminal() {
           if (!it.next())
             throw ed_error("Invalid cursor position.");
           next.col = next_cluster(it.line, cursor.col);
-        } else if (cursor.row + 1 < vase->lines) {
+        } else if (cursor.row < vase->lines) {
           ++next.row;
           next.col = 0;
         } else {