refactor: move alr.sh parsing to pkg

pkg/alrsh/read.go

@@ -0,0 +1,52 @@
+// ALR - Any Linux Repository
+// Copyright (C) 2025 The ALR Authors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package alrsh
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+
+	"mvdan.cc/sh/v3/syntax"
+)
+
+type localFs struct{}
+
+func (fs *localFs) Open(name string) (fs.File, error) {
+	return os.Open(name)
+}
+
+func ReadFromFS(fsys fs.FS, script string) (*ALRSh, error) {
+	fl, err := fsys.Open(script)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open alr.sh: %w", err)
+	}
+	defer fl.Close()
+
+	file, err := syntax.NewParser().Parse(fl, "alr.sh")
+	if err != nil {
+		return nil, err
+	}
+	return &ALRSh{
+		file: file,
+		path: script,
+	}, nil
+}
+
+func ReadFromLocal(script string) (*ALRSh, error) {
+	return ReadFromFS(&localFs{}, script)
+}