add syntax for entries in the root blackboard

include/behaviortree_cpp/basic_types.h

@@ -60,6 +60,8 @@ using StringView = std::string_view;
 
 bool StartWith(StringView str, StringView prefix);
 
+bool StartWith(StringView str, char prefix);
+
 // vector of key/value pairs
 using KeyValueVector = std::vector<std::pair<std::string, std::string>>;
 

include/behaviortree_cpp/scripting/any_types.hpp

@@ -1,4 +1,4 @@
-/*  Copyright (C) 2022 Davide Faconti -  All Rights Reserved
+/*  Copyright (C) 2022-24 Davide Faconti -  All Rights Reserved
 *
 *   Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
 *   to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
@@ -12,14 +12,6 @@
 
 #pragma once
 
-#include <cmath>
-#include <cstdio>
-#include <map>
-#include <string>
-#include <vector>
-#include <utility>
-#include <charconv>
-
 #include "lexy/action/parse.hpp"
 #include "lexy/callback.hpp"
 #include "lexy/dsl.hpp"
@@ -31,6 +23,46 @@ namespace BT::Grammar
 {
 namespace dsl = lexy::dsl;
 
+struct _xid_start_character : lexyd::char_class_base<_xid_start_character>
+{
+  static LEXY_CONSTEVAL auto char_class_name()
+  {
+    return "code-point.BT-start-character";
+  }
+
+  static LEXY_CONSTEVAL auto char_class_ascii()
+  {
+    lexy::_detail::ascii_set result;
+    result.insert('a', 'z');
+    result.insert('A', 'Z');
+    result.insert('_');
+    result.insert('@');
+    return result;
+  }
+
+  static LEXY_UNICODE_CONSTEXPR bool char_class_match_cp(char32_t cp)
+  {
+    // underscore handled as part of ASCII.
+    return lexy::_detail::code_point_has_properties<LEXY_UNICODE_PROPERTY(xid_start)>(cp);
+  }
+
+  template <typename Encoding>
+  static constexpr auto char_class_match_swar(lexy::_detail::swar_int c)
+  {
+    return lexyd::ascii::_alphau::template char_class_match_swar<Encoding>(c);
+  }
+};
+inline constexpr auto xid_start_character = _xid_start_character{};
+
+// A Unicode-aware identifier.
+struct Name
+{
+  static constexpr auto rule =
+      dsl::identifier(xid_start_character, dsl::unicode::xid_continue);
+
+  static constexpr auto value = lexy::as_string<std::string>;
+};
+
 //----------
 struct Integer : lexy::token_production
 {

include/behaviortree_cpp/scripting/operators.hpp

@@ -510,6 +510,10 @@ struct ExprAssignment : ExprBase
       {
         env.vars->createEntry(key, PortInfo());
         entry = env.vars->getEntry(key);
+        if(!entry)
+        {
+          throw LogicError("Bug: report");
+        }
       }
       else
       {
@@ -550,7 +554,8 @@ struct ExprAssignment : ExprBase
         // special case: string to other type.
         // Check if we can use the StringConverter
         auto const str = value.cast<std::string>();
-        const auto& entry_info = env.vars->entryInfo(key);
+        const auto* entry_info = env.vars->entryInfo(key);
+
         if(auto converter = entry_info->converter())
         {
           *dst_ptr = converter(str);
@@ -648,15 +653,6 @@ namespace dsl = lexy::dsl;
 
 constexpr auto escaped_newline = dsl::backslash >> dsl::newline;
 
-// A Unicode-aware identifier.
-struct Name
-{
-  static constexpr auto rule =
-      dsl::identifier(dsl::unicode::xid_start_underscore, dsl::unicode::xid_continue);
-
-  static constexpr auto value = lexy::as_string<std::string>;
-};
-
 // An expression that is nested inside another expression.
 struct nested_expr : lexy::transparent_production
 {

src/basic_types.cpp

@@ -467,4 +467,9 @@ bool StartWith(StringView str, StringView prefix)
          strncmp(str.data(), prefix.data(), prefix.size()) == 0;
 }
 
+bool StartWith(StringView str, char prefix)
+{
+  return str.size() >= 1 && str[0] == prefix;
+}
+
 }  // namespace BT

src/blackboard.cpp

@@ -45,71 +45,51 @@ Any* Blackboard::getAny(const std::string& key)
 const std::shared_ptr<Blackboard::Entry>
 Blackboard::getEntry(const std::string& key) const
 {
-  std::unique_lock<std::mutex> lock(mutex_);
-  auto it = storage_.find(key);
-  if(it != storage_.end())
+  // special syntax: "@" will always refer to the root BB
+  if(StartWith(key, '@'))
   {
-    return it->second;
-  }
-  // not found. Try autoremapping
-  if(auto parent = parent_bb_.lock())
-  {
-    auto remap_it = internal_to_external_.find(key);
-    if(remap_it != internal_to_external_.cend())
+    if(auto parent = parent_bb_.lock())
     {
-      auto const& new_key = remap_it->second;
-      return parent->getEntry(new_key);
+      return parent->getEntry(key);
     }
-    if(autoremapping_ && !IsPrivateKey(key))
+    else
     {
-      return parent->getEntry(key);
+      return getEntry(key.substr(1, key.size() - 1));
     }
   }
-  return {};
-}
 
-std::shared_ptr<Blackboard::Entry> Blackboard::getEntry(const std::string& key)
-{
   std::unique_lock<std::mutex> lock(mutex_);
   auto it = storage_.find(key);
   if(it != storage_.end())
   {
     return it->second;
   }
-
   // not found. Try autoremapping
   if(auto parent = parent_bb_.lock())
   {
     auto remap_it = internal_to_external_.find(key);
     if(remap_it != internal_to_external_.cend())
     {
       auto const& new_key = remap_it->second;
-      auto entry = parent->getEntry(new_key);
-      if(entry)
-      {
-        storage_.insert({ key, entry });
-      }
-      return entry;
+      return parent->getEntry(new_key);
     }
     if(autoremapping_ && !IsPrivateKey(key))
     {
-      auto entry = parent->getEntry(key);
-      if(entry)
-      {
-        storage_.insert({ key, entry });
-      }
-      return entry;
+      return parent->getEntry(key);
     }
   }
   return {};
 }
 
-const TypeInfo* Blackboard::entryInfo(const std::string& key)
+std::shared_ptr<Blackboard::Entry> Blackboard::getEntry(const std::string& key)
 {
-  std::unique_lock<std::mutex> lock(mutex_);
+  return static_cast<const Blackboard&>(*this).getEntry(key);
+}
 
-  auto it = storage_.find(key);
-  return (it == storage_.end()) ? nullptr : &(it->second->info);
+const TypeInfo* Blackboard::entryInfo(const std::string& key)
+{
+  auto entry = getEntry(key);
+  return (!entry) ? nullptr : &(entry->info);
 }
 
 void Blackboard::addSubtreeRemapping(StringView internal, StringView external)
@@ -167,7 +147,21 @@ std::recursive_mutex& Blackboard::entryMutex() const
 
 void Blackboard::createEntry(const std::string& key, const TypeInfo& info)
 {
-  createEntryImpl(key, info);
+  if(StartWith(key, '@'))
+  {
+    if(auto parent = parent_bb_.lock())
+    {
+      parent->createEntry(key, info);
+    }
+    else
+    {
+      createEntryImpl(key.substr(1, key.size() - 1), info);
+    }
+  }
+  else
+  {
+    createEntryImpl(key, info);
+  }
 }
 
 void Blackboard::cloneInto(Blackboard& dst) const

tests/gtest_blackboard.cpp

@@ -557,3 +557,47 @@ TEST(BlackboardTest, BlackboardBackup)
   status = tree.tickWhileRunning();
   ASSERT_EQ(status, BT::NodeStatus::SUCCESS);
 }
+
+TEST(BlackboardTest, RootBlackboard)
+{
+  BT::BehaviorTreeFactory factory;
+
+  const std::string xml_text = R"(
+  <root BTCPP_format="4" >
+    <BehaviorTree ID="SubA">
+      <Sequence>
+        <SubTree ID="SubB" />
+        <Script code=" @var3:=3 " />
+      </Sequence>
+    </BehaviorTree>
+
+    <BehaviorTree ID="SubB">
+      <Sequence>
+        <SaySomething message="{@msg}" />
+        <Script code=" @var4:=4 " />
+      </Sequence>
+    </BehaviorTree>
+
+    <BehaviorTree ID="MainTree">
+      <Sequence>
+        <Script code=" msg:='hello' " />
+        <SubTree ID="SubA" />
+
+        <Script code=" var1:=1 " />
+        <Script code=" @var2:=2 " />
+      </Sequence>
+    </BehaviorTree>
+  </root> )";
+
+  factory.registerNodeType<DummyNodes::SaySomething>("SaySomething");
+  factory.registerBehaviorTreeFromText(xml_text);
+  auto tree = factory.createTree("MainTree");
+
+  auto status = tree.tickWhileRunning();
+  ASSERT_EQ(status, BT::NodeStatus::SUCCESS);
+
+  ASSERT_EQ(1, tree.rootBlackboard()->get<int>("var1"));
+  ASSERT_EQ(2, tree.rootBlackboard()->get<int>("var2"));
+  ASSERT_EQ(3, tree.rootBlackboard()->get<int>("var3"));
+  ASSERT_EQ(4, tree.rootBlackboard()->get<int>("var4"));
+}