1 files changed, 41 insertions, 0 deletions
diff --git a/internal/config/diag.go b/internal/config/diag.go
new file mode 100644
index 0000000..5cee428
--- /dev/null
+++ b/internal/config/diag.go
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+// Package config reads krino's configuration: the main file krino.conf and
+// one file per directory under dirs/. It checks everything it reads and
+// reports every problem with its position.
+package config
+
+import (
+	"fmt"
+
+	"krino/internal/sexp"
+)
+
+// Diag is one problem in a config file.
+type Diag struct {
+	File string
+	Pos  sexp.Pos
+	Msg  string
+}
+
+func (d *Diag) Error() string {
+	if d.Pos.Line == 0 {
+		return fmt.Sprintf("%s: %s", d.File, d.Msg)
+	}
+	return fmt.Sprintf("%s:%d:%d: %s", d.File, d.Pos.Line, d.Pos.Col, d.Msg)
+}
+
+// diags collects the problems found in one file.
+type diags struct {
+	file string
+	list []*Diag
+}
+
+// at records a problem at n's position; a nil n means the whole file.
+func (d *diags) at(n *sexp.Node, format string, args ...any) {
+	var pos sexp.Pos
+	if n != nil {
+		pos = n.Pos
+	}
+	d.list = append(d.list, &Diag{File: d.file, Pos: pos, Msg: fmt.Sprintf(format, args...)})
+}