file iterators refactored

builtin-os-file-iter.go

@@ -5,12 +5,51 @@
 package expr
 
 import (
+	"fmt"
+	"slices"
+
 	"git.portale-stac.it/go-pkg/expr/file"
 	"git.portale-stac.it/go-pkg/expr/kern"
 )
 
 const paramHandleOrPath = "handle-or-path"
 
+type fileIterBase struct {
+	reader    *file.Reader
+	index     int64
+	count     int64
+	autoClose bool
+}
+
+func (it *fileIterBase) Count() int64 {
+	return it.count
+}
+
+func (it *fileIterBase) Index() int64 {
+	return it.index
+}
+
+func (it *fileIterBase) HasOperation(name string) bool {
+	return slices.Contains([]string{kern.NextName, kern.ResetName, kern.IndexName, kern.CountName, kern.CurrentName, kern.CleanName}, name)
+}
+
+func (it *fileIterBase) reset() {
+	it.index = -1
+	it.count = 0
+}
+
+func (it *fileIterBase) increment() {
+	it.index++
+	it.count++
+}
+
+func (it *fileIterBase) repr(typeName string) string {
+	if it.reader.Valid() {
+		return fmt.Sprintf("$(%s@%q)", fileLineIteratorType, it.reader.GetName())
+	}
+	return fmt.Sprintf("$(%s@<nil>)", fileLineIteratorType)
+}
+
 func initFileHandle(ctx kern.ExprContext, name string, args map[string]any) (handle *file.Reader, invalidFileHandle any, autoClose bool, err error) {
 	var ok bool