fix: 3 RDD compat bugs — FIELD->, AsNumInt Double, PACK/ZAP with index

Bug 1: FIELD->NAME in INDEX ON expression
- evalKeyExprInner: strip FIELD->/alias-> prefix before field lookup
- exprToString: handle AliasExpr (FIELD->NAME → "FIELD->NAME")

Bug 2: AsNumInt() on Double returned IEEE 754 raw bits
- Value.AsNumInt(): check tDouble and convert via Float64frombits
- Fixed array index crash when index is result of % modulo

Bug 3: PACK/ZAP crash with open indexes
- OrderListRebuild: fully implemented (was TODO stub)
  Saves index info, closes all, sets idxState=nil, recreates
- OrderCreate: set current=-1 during key evaluation (natural GoTo)
- PACK/ZAP: save/restore idxState, rebuild after operation
- Register __DBPACK, __DBZAP, DBRECALL symbol aliases

Harbour vs Five: 45/47 match (96%), 2 diffs are duplicate-key sort order

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hbrdd/dbf/dbf.go

@@ -631,6 +631,13 @@ func (a *DBFArea) Pack() error {
 		a.flushRecord()
 	}
 
+	// Temporarily disable index to avoid indexed navigation during PACK
+	var savedIdx *indexState
+	if a.idxState != nil {
+		savedIdx = a.idxState
+		a.idxState = nil
+	}
+
 	outRec := uint32(0)
 	buf := make([]byte, a.header.RecordLen)
 
@@ -661,7 +668,7 @@ func (a *DBFArea) Pack() error {
 	// Update header
 	a.updateHeader()
 
-	// Reposition
+	// Reposition (natural order, no index yet)
 	if a.recCount > 0 {
 		a.GoTo(1)
 	} else {
@@ -669,6 +676,14 @@ func (a *DBFArea) Pack() error {
 		a.recNo = 1
 	}
 
+	// Rebuild indexes (record numbers changed after PACK)
+	if savedIdx != nil {
+		a.idxState = savedIdx
+		if err := a.OrderListRebuild(); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
@@ -678,6 +693,13 @@ func (a *DBFArea) Zap() error {
 		return fmt.Errorf("ZAP requires exclusive access")
 	}
 
+	// Save index state
+	var savedIdx *indexState
+	if a.idxState != nil {
+		savedIdx = a.idxState
+		a.idxState = nil
+	}
+
 	a.recCount = 0
 	a.header.RecCount = 0
 
@@ -688,6 +710,13 @@ func (a *DBFArea) Zap() error {
 	a.updateHeader()
 	a.FEof = true
 	a.recNo = 1
+
+	// Rebuild indexes (empty after ZAP)
+	if savedIdx != nil {
+		a.idxState = savedIdx
+		a.OrderListRebuild() // rebuilds empty indexes
+	}
+
 	return nil
 }
 

hbrdd/dbf/indexer.go

@@ -38,6 +38,9 @@ func (a *DBFArea) ensureIndexState() {
 func (a *DBFArea) OrderCreate(params hbrdd.OrderCreateParams) error {
 	a.ensureIndexState()
 
+	// Disable indexed navigation during key evaluation (GoTo must use natural order)
+	a.idxState.current = -1
+
 	idxPath := params.FilePath
 	if idxPath == "" {
 		return fmt.Errorf("index file path required")
@@ -170,8 +173,58 @@ func (a *DBFArea) OrderListFocus(tagName string) error {
 }
 
 // OrderListRebuild rebuilds all indexes.
+// Harbour: ORDLISTREBUILD / REINDEX — recreates all open indexes from current data.
 func (a *DBFArea) OrderListRebuild() error {
-	// TODO: reindex all open indexes
+	if a.idxState == nil || len(a.idxState.indexes) == 0 {
+		return nil
+	}
+
+	// Save current index info
+	savedCurrent := a.idxState.current
+	type idxInfo struct {
+		name    string
+		tag     string
+		keyExpr string
+	}
+	infos := make([]idxInfo, len(a.idxState.indexes))
+	for i := range a.idxState.indexes {
+		infos[i] = idxInfo{
+			name:    a.idxState.names[i],
+			tag:     a.idxState.tags[i],
+			keyExpr: a.idxState.keyExprs[i],
+		}
+	}
+
+	// Close all indexes and disable indexed navigation
+	for _, idx := range a.idxState.indexes {
+		idx.Close()
+	}
+	a.idxState.indexes = nil
+	a.idxState.names = nil
+	a.idxState.tags = nil
+	a.idxState.keyExprs = nil
+	a.idxState.current = -1
+
+	// Remove idxState so GoTo uses natural order during rebuild
+	a.idxState = nil
+
+	// Recreate each index
+	for _, info := range infos {
+		err := a.OrderCreate(hbrdd.OrderCreateParams{
+			KeyExpr:  info.keyExpr,
+			FilePath: info.name,
+			TagName:  info.tag,
+		})
+		if err != nil {
+			return fmt.Errorf("rebuild index %s: %w", info.name, err)
+		}
+	}
+
+	// Restore active index
+	if a.idxState != nil && savedCurrent >= 0 && savedCurrent < len(a.idxState.indexes) {
+		a.idxState.current = savedCurrent
+	}
+
 	return nil
 }
 
@@ -361,10 +414,16 @@ func (a *DBFArea) evalKeyExprInner(expr string) []byte {
 		return []byte(expr[1 : len(expr)-1])
 	}
 
+	// Strip FIELD-> or _FIELD-> or alias-> prefix (Harbour: M->var, FIELD->var)
+	fieldName := upper
+	if idx := strings.Index(fieldName, "->"); idx >= 0 {
+		fieldName = fieldName[idx+2:]
+	}
+
 	// Simple field name
 	for i := 0; i < a.FieldCount(); i++ {
 		fi := a.GetFieldInfo(i)
-		if strings.ToUpper(fi.Name) == upper {
+		if strings.ToUpper(fi.Name) == fieldName {
 			val, _ := a.GetValue(i)
 			return formatKeyValue(val, fi)
 		}