Improve insertion and removal of 'or if' conditionals.

Allow inserting an 'or if' immediately after 'if', 'else if', 'or if'.
Removing an 'or if' no longer removes the associated block.

src/tracerestrict.cpp

@@ -807,7 +807,7 @@ CommandCost CmdProgramSignalTraceRestrict(TileIndex tile, DoCommandFlag flags, u
 
 		case TRDCT_REMOVE_ITEM: {
 			TraceRestrictItem old_item = *TraceRestrictProgram::InstructionAt(items, offset);
-			if (IsTraceRestrictConditional(old_item)) {
+			if (IsTraceRestrictConditional(old_item) && GetTraceRestrictCondFlags(old_item) != TRCF_OR) {
 				bool remove_whole_block = false;
 				if (GetTraceRestrictCondFlags(old_item) == 0) {
 					if (GetTraceRestrictType(old_item) == TRIT_COND_ENDIF) {

src/tracerestrict_gui.cpp

@@ -115,18 +115,20 @@ struct TraceRestrictDropDownListSet {
 static const StringID _program_insert_str[] = {
 	STR_TRACE_RESTRICT_CONDITIONAL_IF,
 	STR_TRACE_RESTRICT_CONDITIONAL_ELIF,
+	STR_TRACE_RESTRICT_CONDITIONAL_ORIF,
 	STR_TRACE_RESTRICT_CONDITIONAL_ELSE,
 	STR_TRACE_RESTRICT_PF_DENY,
 	STR_TRACE_RESTRICT_PF_PENALTY,
 	INVALID_STRING_ID
 };
-static const uint _program_insert_else_flag = 0x100;           ///< flag to indicate that TRCF_ELSE should be set
-static const uint32 _program_insert_else_hide_mask = 4;        ///< disable bitmask for else
+static const uint32 _program_insert_else_hide_mask    = 8;     ///< disable bitmask for else
+static const uint32 _program_insert_or_if_hide_mask   = 4;     ///< disable bitmask for elif
 static const uint32 _program_insert_else_if_hide_mask = 2;     ///< disable bitmask for elif
 static const uint _program_insert_val[] = {
 	TRIT_COND_UNDEFINED,                               // if block
-	TRIT_COND_UNDEFINED | _program_insert_else_flag,   // elif block
-	TRIT_COND_ENDIF | _program_insert_else_flag,       // else block
+	TRIT_COND_UNDEFINED | (TRCF_ELSE << 16),           // elif block
+	TRIT_COND_UNDEFINED | (TRCF_OR << 16),             // orif block
+	TRIT_COND_ENDIF | (TRCF_ELSE << 16),               // else block
 	TRIT_PF_DENY,                                      // deny
 	TRIT_PF_PENALTY,                                   // penalty
 };
@@ -732,7 +734,7 @@ public:
 					return;
 				}
 
-				uint32 disabled = 0;
+				uint32 disabled = _program_insert_or_if_hide_mask;
 				TraceRestrictItem item = this->GetSelected();
 				if (GetTraceRestrictType(item) == TRIT_COND_ENDIF ||
 						(IsTraceRestrictConditional(item) && GetTraceRestrictCondFlags(item) != 0)) {
@@ -744,6 +746,15 @@ public:
 					// can't insert else/end if here
 					disabled |= _program_insert_else_hide_mask | _program_insert_else_if_hide_mask;
 				}
+				if (this->selected_instruction > 1) {
+					TraceRestrictItem prev_item = this->GetItem(this->GetProgram(), this->selected_instruction - 1);
+					if (IsTraceRestrictConditional(prev_item) && GetTraceRestrictType(prev_item) != TRIT_COND_ENDIF) {
+						// previous item is either: an if, or an else/or if
+
+						// else if has same validation rules as or if, use it instead of creating another test function
+						if (ElseIfInsertionDryRun(false)) disabled &= ~_program_insert_or_if_hide_mask;
+					}
+				}
 
 				this->ShowDropDownListWithValue(&_program_insert, 0, true, TR_WIDGET_INSERT, disabled, 0, 0);
 				break;
@@ -914,13 +925,10 @@ public:
 			case TR_WIDGET_INSERT: {
 				TraceRestrictItem insert_item = 0;
 
-				bool have_else = false;
-				if (value & _program_insert_else_flag) {
-					value &= ~_program_insert_else_flag;
-					have_else = true;
-				}
+				TraceRestrictCondFlags cond_flags = static_cast<TraceRestrictCondFlags>(value >> 16);
+				value &= 0xFFFF;
 				SetTraceRestrictTypeAndNormalise(insert_item, static_cast<TraceRestrictItemType>(value));
-				if (have_else) SetTraceRestrictCondFlags(insert_item, TRCF_ELSE); // this needs to happen after calling SetTraceRestrictTypeAndNormalise
+				SetTraceRestrictCondFlags(insert_item, cond_flags); // this needs to happen after calling SetTraceRestrictTypeAndNormalise
 
 				this->expecting_inserted_item = insert_item;
 				TraceRestrictDoCommandP(this->tile, this->track, TRDCT_INSERT_ITEM, this->selected_instruction - 1, insert_item, STR_TRACE_RESTRICT_ERROR_CAN_T_INSERT_ITEM);