Ruby: use Gui module to get selected unit

This allows "exterminate it" to work from command-prompt, among other things.

Fixes #1100

plugins/ruby/ruby.cpp

@@ -5,9 +5,11 @@
 #include "PluginManager.h"
 #include "VersionInfo.h"
 #include "MemAccess.h"
-
 #include "DataDefs.h"
+
+#include "modules/Gui.h"
 #include "df/global_objects.h"
+#include "df/unit.h"
 
 #include "tinythread.h"
 
@@ -627,6 +629,12 @@ static VALUE rb_dfget_vtable_ptr(VALUE self, VALUE objptr)
     return rb_uint2inum(*(uintptr_t*)rb_num2ulong(objptr));
 }
 
+static VALUE rb_dfget_selected_unit_id(VALUE self)
+{
+    df::unit *u = Gui::getAnyUnit(Core::getTopViewscreen());
+    return rb_int2inum(u ? u->id : -1);
+}
+
 // run a dfhack command, as if typed from the dfhack console
 static VALUE rb_dfhack_run(VALUE self, VALUE cmd)
 {
@@ -1138,6 +1146,7 @@ static void ruby_bind_dfhack(void) {
     rb_define_singleton_method(rb_cDFHack, "get_vtable", RUBY_METHOD_FUNC(rb_dfget_vtable), 1);
     rb_define_singleton_method(rb_cDFHack, "get_rtti_classname", RUBY_METHOD_FUNC(rb_dfget_rtti_classname), 1);
     rb_define_singleton_method(rb_cDFHack, "get_vtable_ptr", RUBY_METHOD_FUNC(rb_dfget_vtable_ptr), 1);
+    rb_define_singleton_method(rb_cDFHack, "get_selected_unit_id", RUBY_METHOD_FUNC(rb_dfget_selected_unit_id), 0);
     rb_define_singleton_method(rb_cDFHack, "dfhack_run", RUBY_METHOD_FUNC(rb_dfhack_run), 1);
     rb_define_singleton_method(rb_cDFHack, "print_str", RUBY_METHOD_FUNC(rb_dfprint_str), 1);
     rb_define_singleton_method(rb_cDFHack, "print_color", RUBY_METHOD_FUNC(rb_dfprint_color), 2);

plugins/ruby/unit.rb

@@ -6,43 +6,7 @@ module DFHack
         # with an argument that respond to x/y/z (eg cursor), find first unit at this position
         def unit_find(what=:selected, y=nil, z=nil)
             if what == :selected
-                case curview._rtti_classname
+                return world.units.all.binsearch(df.get_selected_unit_id)
-                when :viewscreen_itemst
-                    ref = curview.entry_ref[curview.cursor_pos]
-                    ref.unit_tg if ref.kind_of?(GeneralRefUnit)
-                when :viewscreen_unitlistst
-                    v = curview
-                    v.units[v.page][v.cursor_pos[v.page]]
-                when :viewscreen_petst
-                    v = curview
-                    case v.mode
-                    when :List
-                        v.animal[v.cursor].unit if !v.is_vermin[v.cursor]
-                    when :SelectTrainer
-                        v.trainer_unit[v.trainer_cursor]
-                    end
-                when :viewscreen_dwarfmodest
-                    case ui.main.mode
-                    when :ViewUnits
-                        # nobody selected => idx == 0
-                        v = world.units.active[ui_selected_unit]
-                        v if v and v.pos.z == cursor.z
-                    when :LookAround
-                        k = ui_look_list.items[ui_look_cursor]
-                        k.unit if k.type == :Unit
-                    else
-                        ui.follow_unit_tg if ui.follow_unit != -1
-                    end
-                when :viewscreen_dungeonmodest
-                    case ui_advmode.menu
-                    when :Default
-                        world.units.active[0]
-                    else
-                        unit_find(cursor)   # XXX
-                    end
-                when :viewscreen_dungeon_monsterstatusst
-                    curview.unit
-                end
             elsif what.kind_of?(Integer)
                 # search by id
                 return world.units.all.binsearch(what) if not z