Flatten structure

Related to #13

1 files changed, 127 insertions, 0 deletions

diff --git a/prelude.go b/prelude.go
new file mode 100644
index 0000000..d109a82
--- /dev/null
+++ b/prelude.go
@@ -0,0 +1,127 @@
+// Copyright Nicolas Paul (2023)
+//
+// * Nicolas Paul
+//
+// This software is a computer program whose purpose is to allow the hosting
+// and sharing of Go modules using a personal domain.
+//
+// This software is governed by the CeCILL license under French law and
+// abiding by the rules of distribution of free software.  You can  use,
+// modify and/ or redistribute the software under the terms of the CeCILL
+// license as circulated by CEA, CNRS and INRIA at the following URL
+// "http://www.cecill.info".
+//
+// As a counterpart to the access to the source code and  rights to copy,
+// modify and redistribute granted by the license, users are provided only
+// with a limited warranty  and the software's author,  the holder of the
+// economic rights,  and the successive licensors  have only  limited
+// liability.
+//
+// In this respect, the user's attention is drawn to the risks associated
+// with loading,  using,  modifying and/or developing or reproducing the
+// software by the user in light of its specific status of free software,
+// that may mean  that it is complicated to manipulate,  and  that  also
+// therefore means  that it is reserved for developers  and  experienced
+// professionals having in-depth computer knowledge. Users are therefore
+// encouraged to load and test the software's suitability as regards their
+// requirements in conditions enabling the security of their systems and/or
+// data to be ensured and,  more generally, to use and operate it in the
+// same conditions as regards security.
+//
+// The fact that you are presently reading this means that you have had
+// knowledge of the CeCILL license and that you accept its terms.
+
+// Prelude for the Starlark environment.
+
+package main
+
+import (
+	"fmt"
+	"go.starlark.net/starlark"
+	"strings"
+)
+
+// https://stackoverflow.com/questions/1976007/what-characters-are-forbidden-in-windows-and-linux-directory-names
+const invalidName string = "..\\/<>:\"|?* \t\n\r\b\findex"
+
+// Registered represents the index of registered modules.
+var Registered Index
+
+// InternIndex represents the built-in function "index".
+// index(domain) initializes a new index with the given domain.
+func InternIndex(_ *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple,
+	kwargs []starlark.Tuple) (starlark.Value, error) {
+	var domain string
+	if err := starlark.UnpackArgs("index", args, kwargs,
+		"domain", &domain); err != nil {
+		return nil, err
+	}
+
+	Registered.Domain = domain
+
+	return starlark.None, nil
+}
+
+// InternModule represents the built-in function "module".
+// module(name, vcs, repo, dir, file) registers a new module into the
+// index.
+func InternModule(_ *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple,
+	kwargs []starlark.Tuple) (starlark.Value, error) {
+
+	var name, vcs, repo, dir, file string
+	if err := starlark.UnpackArgs("module", args, kwargs, "name",
+		&name, "vcs", &vcs, "repo", &repo, "dir", &dir, "file", &file); err != nil {
+		return nil, err
+	}
+
+	if Registered.Domain == "" {
+		return nil, fmt.Errorf("index not initialized")
+	}
+
+	if name == "" {
+		return nil, fmt.Errorf("module name cannot be empty")
+	}
+
+	if vcs == "" {
+		return nil, fmt.Errorf("module %q vcs cannot be empty", name)
+	}
+
+	if repo == "" {
+		return nil, fmt.Errorf("module %q repo cannot be empty", name)
+	}
+
+	// Check for name conditions.
+	if strings.Contains(invalidName, name) {
+		return nil, fmt.Errorf("module %q name is invalid", name)
+	}
+
+	if Registered.CheckModule(name) {
+		return nil, fmt.Errorf("module %q already exists", name)
+	}
+
+	var v Vcs
+	switch vcs {
+	case "git":
+		v = VcsGit
+	case "hg":
+		v = VcsMercurial
+	case "svn":
+		v = VcsSubversion
+	case "fossil":
+		v = VcsFossil
+	case "bzr":
+		v = VcsBazaar
+	default:
+		return nil, fmt.Errorf("unknown vcs %q", vcs)
+	}
+
+	Registered.AddModule(name, &Module{
+		Path: name,
+		Vcs:  v,
+		Repo: repo,
+		Dir:  dir,
+		File: file,
+	})
+
+	return starlark.None, nil
+}