Finish deploying DEFINE_WFL_FUNCTION macro

src/ai/contexts.cpp

@@ -1229,7 +1229,7 @@ void readonly_context_impl::set_src_dst_enemy_valid_lua()
 	src_dst_enemy_valid_lua_ = true;
 }
 
-const map_location& readonly_context_impl::suitable_keep(const map_location& leader_location, const pathfind::paths& leader_paths){
+const map_location& readonly_context_impl::suitable_keep(const map_location& leader_location, const pathfind::paths& leader_paths) const {
 	if (resources::gameboard->map().is_keep(leader_location)) {
 		return leader_location; //if leader already on keep, then return leader_location
 	}

src/ai/contexts.hpp

@@ -396,7 +396,7 @@ class readonly_context : public virtual side_context {
 	virtual void set_dst_src_enemy_valid_lua() = 0;
 
 	/** get most suitable keep for leader - nearest free that can be reached in 1 turn, if none - return nearest occupied that can be reached in 1 turn, if none - return nearest keep, if none - return null_location */
-	virtual const map_location& suitable_keep( const map_location& leader_location, const pathfind::paths& leader_paths ) = 0;
+	virtual const map_location& suitable_keep( const map_location& leader_location, const pathfind::paths& leader_paths ) const = 0;
 
 	/**
 	 * serialize to config
@@ -977,7 +977,7 @@ class readonly_context_proxy : public virtual readonly_context, public virtual s
 		target_->set_src_dst_enemy_valid_lua();
 	}
 
-	virtual const map_location& suitable_keep( const map_location& leader_location, const pathfind::paths& leader_paths ) override
+	virtual const map_location& suitable_keep( const map_location& leader_location, const pathfind::paths& leader_paths ) const override
 	{
 		return target_->suitable_keep(leader_location, leader_paths);
 	}
@@ -1485,7 +1485,7 @@ class readonly_context_impl : public virtual side_context_proxy, public readonly
 
 	virtual void set_src_dst_enemy_valid_lua() override;
 
-	virtual const map_location& suitable_keep( const map_location& leader_location, const pathfind::paths& leader_paths ) override;
+	virtual const map_location& suitable_keep( const map_location& leader_location, const pathfind::paths& leader_paths ) const override;
 
 
 	virtual config to_readonly_context_config() const override;

src/ai/formula/ai.cpp

@@ -140,7 +140,7 @@ void formula_ai::display_message(const std::string& msg) const
 
 }
 
-formula_ptr formula_ai::create_optional_formula(const std::string& formula_string){
+formula_ptr formula_ai::create_optional_formula(const std::string& formula_string) const {
 	try{
 		return formula::create_optional_formula(formula_string, &function_table_);
 	}

src/ai/formula/ai.hpp

@@ -136,7 +136,7 @@ class formula_ai : public readonly_context_proxy, public wfl::formula_callable {
 	*   @return pointer to created function or
 	*   @retval game_logic::formula_ptr() if there were any problems
 	*/
-	wfl::formula_ptr create_optional_formula(const std::string& formula_string);
+	wfl::formula_ptr create_optional_formula(const std::string& formula_string) const;
 
 	wfl::candidate_action_ptr load_candidate_action_from_config(const config& cfg);
 
@@ -168,7 +168,9 @@ class formula_ai : public readonly_context_proxy, public wfl::formula_callable {
 
 //	gamestate_change_observer infinite_loop_guardian_;
 	wfl::map_formula_callable vars_;
-	wfl::ai_function_symbol_table function_table_;
+	// Making this mutable is a bit of a hack, but I don't have a better idea.
+	// (It's needed because a formula could define new functions.)
+	mutable wfl::ai_function_symbol_table function_table_;
 
 	friend class ai_default;
 	friend ai_context& get_ai_context(wfl::const_formula_callable_ptr for_fai);