1 files changed, 54 insertions, 1 deletions
diff --git a/flag.go b/flag.go
index 2673c7a..645cb83 100644
--- a/flag.go
+++ b/flag.go
@@ -1,8 +1,20 @@
 package complete
 
+import (
+	"os"
+	"path/filepath"
+)
+
 type FlagOptions struct {
 	HasFollow      bool
-	FollowsOptions []string
+	FollowsOptions func() []Option
+}
+
+func (f *FlagOptions) follows() []Option {
+	if f.FollowsOptions == nil {
+		return nil
+	}
+	return f.FollowsOptions()
 }
 
 var (
@@ -10,3 +22,44 @@ var (
 	FlagUnknownFollow = FlagOptions{HasFollow: true}
 )
 
+func FlagFileFilter(pattern string) FlagOptions {
+	return FlagOptions{
+		HasFollow:      true,
+		FollowsOptions: glob(pattern),
+	}
+}
+
+func glob(pattern string) func() []Option {
+	return func() []Option {
+		files, err := filepath.Glob(pattern)
+		if err != nil {
+			logger("failed glob operation with pattern '%s': %s", pattern, err)
+		}
+		if !filepath.IsAbs(pattern) {
+			filesToRel(files)
+		}
+		options := make([]Option, len(files))
+		for i, f := range files {
+			options[i] = ArgFileName(f)
+		}
+		return options
+	}
+}
+func filesToRel(files []string) {
+	wd, err := os.Getwd()
+	if err != nil {
+		return
+	}
+	for i := range files {
+		abs, err := filepath.Abs(files[i])
+		if err != nil {
+			continue
+		}
+		rel, err := filepath.Rel(wd, abs)
+		if err != nil {
+			continue
+		}
+		files[i] = "./" + rel
+	}
+	return
+}