- allow struct extensions in zscript.

This is mainly for splitting the Doom specific content off the main definitions for easier reuse.

src/common/scripting/frontend/zcc-parse.lemon

@@ -234,6 +234,7 @@ class_head(X) ::= EXTEND CLASS(T) IDENTIFIER(A).
 	X = head;
 }
 
+
 class_head(X) ::= CLASS(T) IDENTIFIER(A) class_ancestry(B) class_flags(C).
 {
 	NEW_AST_NODE(Class,head,T);
@@ -394,6 +395,17 @@ struct_def(X) ::= STRUCT(T) IDENTIFIER(A) struct_flags(S) LBRACE opt_struct_body
 	X = def;
 }
 
+struct_def(X) ::= EXTEND STRUCT(T) IDENTIFIER(A) LBRACE opt_struct_body(B) RBRACE opt_semicolon.
+{
+	NEW_AST_NODE(Struct,def,T);
+	def->NodeName = A.Name();
+	def->Body = B;
+	def->Type = nullptr;
+	def->Symbol = nullptr;
+	def->Flags = ZCC_Extension;
+	X = def;
+}
+
 %type struct_flags{ClassFlagsBlock}
 struct_flags(X) ::= .										{ X.Flags = 0; X.Version = {0, 0}; }
 struct_flags(X) ::= struct_flags(A) UI.						{ X.Flags = A.Flags | ZCC_UIFlag; }

src/common/scripting/frontend/zcc_compile.cpp

@@ -377,8 +377,30 @@ void ZCCCompiler::ProcessMixin(ZCC_MixinDef *cnode, PSymbolTreeNode *treenode)
 
 void ZCCCompiler::ProcessStruct(ZCC_Struct *cnode, PSymbolTreeNode *treenode, ZCC_Class *outer)
 {
-	Structs.Push(new ZCC_StructWork(static_cast<ZCC_Struct *>(cnode), treenode, outer));
-	ZCC_StructWork *cls = Structs.Last();
+	ZCC_StructWork* cls = nullptr;
+
+	// If this is a struct extension, put the new node directly into the existing class.
+	if (cnode->Flags == ZCC_Extension)
+	{
+		for (auto strct : Structs)
+		{
+			if (strct->NodeName() == cnode->NodeName)
+			{
+				cls = strct;
+				break;
+			}
+		}
+		if (cls == nullptr)
+		{
+			Error(cnode, "Struct %s cannot be found in the current translation unit.", FName(cnode->NodeName).GetChars());
+			return;
+		}
+	}
+	else
+	{
+		Structs.Push(new ZCC_StructWork(static_cast<ZCC_Struct*>(cnode), treenode, outer));
+		cls = Structs.Last();
+	}
 
 	auto node = cnode->Body;
 	PSymbolTreeNode *childnode;
@@ -494,7 +516,15 @@ ZCCCompiler::ZCCCompiler(ZCC_AST &ast, DObject *_outer, PSymbolTable &_symbols,
 					ProcessClass(static_cast<ZCC_Class *>(node), tnode);
 					break;
 				}
+				goto common;
 			case AST_Struct:
+				if (static_cast<ZCC_Class*>(node)->Flags == ZCC_Extension)
+				{
+					ProcessStruct(static_cast<ZCC_Struct*>(node), tnode, nullptr);
+					break;
+				}
+
+			common:
 			case AST_ConstantDef:
 			case AST_Enum:
 				if ((tnode = AddTreeNode(static_cast<ZCC_NamedNode *>(node)->NodeName, node, GlobalTreeNodes)))

wadsrc/static/zscript.txt

@@ -1,5 +1,6 @@
 version "4.5"
 #include "zscript/base.zs"
+#include "zscript/doombase.zs"
 #include "zscript/sounddata.zs"
 #include "zscript/mapdata.zs"
 #include "zscript/dynarrays.zs"

wadsrc/static/zscript/base.zs

@@ -2,22 +2,13 @@
 struct _ native	// These are the global variables, the struct is only here to avoid extending the parser for this.
 {
 	native readonly Array<class> AllClasses;
-	native readonly Array<class<Actor> > AllActorClasses;
-	native readonly Array<@PlayerClass> PlayerClasses;
-	native readonly Array<@PlayerSkin> PlayerSkins;
-	native readonly Array<@Team> Teams;
-	native int validcount;
 	native readonly bool multiplayer;
 	native @KeyBindings Bindings;
 	native @KeyBindings AutomapBindings;
-	native play @DehInfo deh;
 	native readonly @GameInfoStruct gameinfo;
 	native readonly ui bool netgame;
-
-	native readonly bool automapactive;
 	native readonly uint gameaction;
 	native readonly int gamestate;
-	native readonly TextureID skyflatnum;
 	native readonly Font smallfont;
 	native readonly Font smallfont2;
 	native readonly Font bigfont;
@@ -38,27 +29,14 @@ struct _ native	// These are the global variables, the struct is only here to av
 	native readonly int CleanHeight_1;
 	native ui int menuactive;
 	native readonly @FOptionMenuSettings OptionMenuSettings;
-	native readonly int gametic;
 	native readonly bool demoplayback;
 	native ui int BackbuttonTime;
 	native ui float BackbuttonAlpha;
-	native readonly int Net_Arbitrator;
-	native ui BaseStatusBar StatusBar;
-	native readonly Weapon WP_NOCHANGE;
-	deprecated("3.8", "Use Actor.isFrozen() or Level.isFrozen() instead") native readonly bool globalfreeze;
-	native int LocalViewPitch;
 	native readonly @MusPlayingInfo musplaying;
 	native readonly bool generic_ui;
 	native readonly int GameTicRate;
 	native MenuCustomize menuCustomizer;
-
-// sandbox state in multi-level setups:
-
-	native play @PlayerInfo players[MAXPLAYERS];
-	native readonly bool playeringame[MAXPLAYERS];
 	native readonly int consoleplayer;
-	native play LevelLocals Level;
-
 }
 
 struct MusPlayingInfo native

wadsrc/static/zscript/doombase.zs

@@ -0,0 +1,24 @@
+
+extend struct _
+{
+	native readonly Array<class<Actor> > AllActorClasses;
+	native readonly Array<@PlayerClass> PlayerClasses;
+	native readonly Array<@PlayerSkin> PlayerSkins;
+	native readonly Array<@Team> Teams;
+	native int validcount;
+	native play @DehInfo deh;
+	native readonly bool automapactive;
+	native readonly TextureID skyflatnum;
+	native readonly int gametic;
+	native readonly int Net_Arbitrator;
+	native ui BaseStatusBar StatusBar;
+	native readonly Weapon WP_NOCHANGE;
+	deprecated("3.8", "Use Actor.isFrozen() or Level.isFrozen() instead") native readonly bool globalfreeze;
+	native int LocalViewPitch;
+	
+	// sandbox state in multi-level setups:
+	native play @PlayerInfo players[MAXPLAYERS];
+	native readonly bool playeringame[MAXPLAYERS];
+	native play LevelLocals Level;
+
+}