config and engine can load with unsaved text

1 files changed, 20 insertions, 2 deletions

diff --git a/internal/config/load.go b/internal/config/load.go
index cd4d97c..3811802 100644
--- a/internal/config/load.go
+++ b/internal/config/load.go
@@ -20,6 +20,15 @@ type Config struct {
 	Dirs []*Dir
 }
 
+// readSource is the text of file: the caller's override when it has one,
+// else the file's own bytes.
+func readSource(overrides map[string][]byte, file string) ([]byte, error) {
+	if src, ok := overrides[file]; ok {
+		return src, nil
+	}
+	return os.ReadFile(file)
+}
+
 // DefaultFile is krino.conf in the XDG config directory.
 func DefaultFile() string {
 	return filepath.Join(xdg.ConfigHome(), "krino", "krino.conf")
@@ -34,7 +43,16 @@ func DirFile(mainFile, name string) string {
 // With names, only those directories are read, and each must be included.
 // The Config is nil only when the main file itself cannot be read.
 func Load(mainFile string, names ...string) (*Config, []*Diag) {
-	src, err := os.ReadFile(mainFile)
+	return LoadWith(mainFile, nil, names...)
+}
+
+// LoadWith is Load with some files' text supplied by the caller: overrides
+// maps a file path - mainFile, or DirFile(mainFile, name) - to the text to
+// read instead of that file's own, so an editor can have unsaved text
+// checked exactly as a run would read it (GUI design §1.3). A nil map is
+// Load.
+func LoadWith(mainFile string, overrides map[string][]byte, names ...string) (*Config, []*Diag) {
+	src, err := readSource(overrides, mainFile)
 	if errors.Is(err, fs.ErrNotExist) {
 		return nil, []*Diag{{File: mainFile, Msg: "not found; create it with: krino init"}}
 	}
@@ -62,7 +80,7 @@ func Load(mainFile string, names ...string) (*Config, []*Diag) {
 	}
 	for _, name := range want {
 		file := DirFile(mainFile, name)
-		src, err := os.ReadFile(file)
+		src, err := readSource(overrides, file)
 		if err != nil {
 			msg := err.Error()
 			if errors.Is(err, fs.ErrNotExist) {