Add mshFileManager builtin

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- `mshFileManager` builtin: pops a starting directory from the stack, opens the file manager, and cds to the final directory on exit
+- `msh fm` now accepts an optional starting directory argument
 - Built-in file manager via `msh fm` subcommand and Ctrl-O in interactive mode
   - Dual-pane layout with directory listing and file/directory preview
   - Vim-style navigation (`j`/`k`, `h`/`l`, `gg`/`G`, Ctrl-u/Ctrl-d)

doc/mshell.md

@@ -534,6 +534,10 @@ end
 - `readTsvFile`: Read a TSV file into list of list of strings. `(str -- [[str]])`
 - `cd`: Change directory `(str -- )`
 - `pwd`: Get current working directory `( -- str)`
+- `mshFileManager`: Open the built-in file manager.
+Pops a starting directory from the stack.
+On exit, changes the working directory to the directory the user navigated to.
+`(str -- )`
 - `writeFile`: Write string to file (UTF-8). Overwrites file if it exists. `(str content str file -- )`
 - `appendFile`: Append string to file (UTF-8). `(str content str file -- )`
 - `fileSize`: Get size of file in bytes. Returns a Maybe in case file doesn't exist or other IO error. `(str -- Maybe int)`

mshell/BuiltInList.go

@@ -84,6 +84,7 @@ var BuiltInList = map[string]struct{}{
 	"mkdir": {},
 	"mkdirp": {},
 	"mod": {},
+	"mshFileManager": {},
 	"month": {},
 	"mv": {},
 	"nip": {},

mshell/Evaluator.go

@@ -2206,6 +2206,24 @@ MainLoop:
 					if !result.Success {
 						return result
 					}
+				} else if t.Lexeme == "mshFileManager" {
+					obj, err := stack.Pop()
+					if err != nil {
+						return state.FailWithMessage(fmt.Sprintf("%d:%d: Cannot do 'mshFileManager' on an empty stack.\n", t.Line, t.Column))
+					}
+
+					dir, err := obj.CastString()
+					if err != nil {
+						return state.FailWithMessage(fmt.Sprintf("%d:%d: Cannot use a %s as a starting directory for mshFileManager.\n", t.Line, t.Column, obj.TypeName()))
+					}
+
+					newDir := RunFileManagerBuiltin(dir)
+					if newDir != "" {
+						result, _, _, _ := state.ChangeDirectory(newDir)
+						if !result.Success {
+							return result
+						}
+					}
 				} else if t.Lexeme == "in" {
 					substring, stringOrDict, err := stack.Pop2(t)
 					if err != nil {

mshell/FileManager.go

@@ -51,11 +51,15 @@ type FileManager struct {
 	renaming       bool
 	renameInput    []rune
 	renameCursor   int // cursor position within renameInput
+
+	// Status message (shown once at bottom, cleared on first keypress)
+	statusMsg string
 }
 
 // RunFileManager runs as a standalone subcommand (msh fm).
 // TUI goes to /dev/tty, final directory is printed to stdout.
-func RunFileManager() int {
+// If startDir is non-empty and is a valid directory, it is used instead of cwd.
+func RunFileManager(startDir string) int {
 	fm := &FileManager{}
 	fm.stdInFd = int(os.Stdin.Fd())
 
@@ -83,10 +87,23 @@ func RunFileManager() int {
 	fm.initUserInfo()
 	fm.bookmarks = loadBookmarks()
 
-	fm.currentDir, err = os.Getwd()
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Error getting working directory: %s\n", err)
-		return 1
+	if startDir != "" {
+		if info, err := os.Stat(startDir); err == nil && info.IsDir() {
+			fm.currentDir, _ = filepath.Abs(startDir)
+		} else {
+			fm.statusMsg = fmt.Sprintf("Directory not found: %s", startDir)
+			fm.currentDir, err = os.Getwd()
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Error getting working directory: %s\n", err)
+				return 1
+			}
+		}
+	} else {
+		fm.currentDir, err = os.Getwd()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error getting working directory: %s\n", err)
+			return 1
+		}
 	}
 
 	fm.loadDirectory()
@@ -115,8 +132,9 @@ func RunFileManager() int {
 
 // RunFileManagerInteractive runs from within the mshell interactive session.
 // The terminal is already in raw mode from the interactive session.
+// If startDir is non-empty and is a valid directory, it is used instead of cwd.
 // Returns the directory the user was in when they quit.
-func RunFileManagerInteractive(stdInFd int, oldState *term.State) string {
+func RunFileManagerInteractive(stdInFd int, oldState *term.State, startDir string) string {
 	fm := &FileManager{}
 	fm.stdInFd = stdInFd
 	fm.oldState = *oldState
@@ -132,7 +150,16 @@ func RunFileManagerInteractive(stdInFd int, oldState *term.State) string {
 	fm.initUserInfo()
 	fm.bookmarks = loadBookmarks()
 
-	fm.currentDir, _ = os.Getwd()
+	if startDir != "" {
+		if info, err := os.Stat(startDir); err == nil && info.IsDir() {
+			fm.currentDir, _ = filepath.Abs(startDir)
+		} else {
+			fm.statusMsg = fmt.Sprintf("Directory not found: %s", startDir)
+			fm.currentDir, _ = os.Getwd()
+		}
+	} else {
+		fm.currentDir, _ = os.Getwd()
+	}
 	fm.loadDirectory()
 
 	// Terminal is already in raw mode from the interactive session.
@@ -146,6 +173,55 @@ func RunFileManagerInteractive(stdInFd int, oldState *term.State) string {
 	return fm.currentDir
 }
 
+// RunFileManagerBuiltin runs from a builtin call during evaluation.
+// The terminal is in cooked mode, so this handles MakeRaw/Restore itself.
+// If startDir is non-empty and is a valid directory, it is used instead of cwd.
+// Returns the directory the user was in when they quit.
+func RunFileManagerBuiltin(startDir string) string {
+	fm := &FileManager{}
+	fm.stdInFd = int(os.Stdin.Fd())
+	fm.ttyOut = os.Stdout
+
+	cols, rows, err := term.GetSize(int(os.Stdout.Fd()))
+	if err != nil {
+		return ""
+	}
+	fm.rows = rows
+	fm.cols = cols
+
+	fm.initUserInfo()
+	fm.bookmarks = loadBookmarks()
+
+	if startDir != "" {
+		if info, err := os.Stat(startDir); err == nil && info.IsDir() {
+			fm.currentDir, _ = filepath.Abs(startDir)
+		} else {
+			fm.statusMsg = fmt.Sprintf("Directory not found: %s", startDir)
+			fm.currentDir, _ = os.Getwd()
+		}
+	} else {
+		fm.currentDir, _ = os.Getwd()
+	}
+	fm.loadDirectory()
+
+	oldState, err := term.MakeRaw(fm.stdInFd)
+	if err != nil {
+		return ""
+	}
+	fm.oldState = *oldState
+
+	fm.ttyOut.WriteString("\033[?1049h\033[?25l")
+
+	defer func() {
+		fm.ttyOut.WriteString("\033[?25h\033[?1049l")
+		term.Restore(fm.stdInFd, &fm.oldState)
+	}()
+
+	fm.mainLoop()
+
+	return fm.currentDir
+}
+
 func (fm *FileManager) initUserInfo() {
 	fm.hostname, _ = os.Hostname()
 	if u, err := user.Current(); err == nil {
@@ -188,7 +264,7 @@ func (fm *FileManager) loadDirectory() {
 }
 
 func (fm *FileManager) visibleRows() int {
-	if fm.searching || fm.renaming {
+	if fm.searching || fm.renaming || fm.statusMsg != "" {
 		return fm.rows - 2 // header + bottom bar
 	}
 	return fm.rows - 1 // header only
@@ -481,6 +557,19 @@ func (fm *FileManager) render() {
 		buf.WriteString("\033[?25h")
 	}
 
+	// Status message at the bottom
+	if fm.statusMsg != "" && !fm.searching && !fm.renaming {
+		buf.WriteString("\r\n")
+		msg := fm.statusMsg
+		msgRunes := utf8.RuneCountInString(msg)
+		if msgRunes > fm.cols {
+			msg = string([]rune(msg)[:fm.cols])
+		}
+		buf.WriteString("\033[33m") // yellow
+		buf.WriteString(msg)
+		buf.WriteString("\033[0m")
+	}
+
 	// Bookmark overlay
 	if fm.pendingMark || fm.showingBookmarks {
 		fm.renderBookmarkOverlay(&buf)
@@ -644,6 +733,8 @@ func (fm *FileManager) handleInput() bool {
 		return false
 	}
 
+	fm.statusMsg = ""
+
 	if fm.searching {
 		return fm.handleSearchInput(buf, n)
 	}

mshell/Main.go

@@ -88,7 +88,11 @@ func main() {
 	}
 
 	if len(os.Args) >= 2 && os.Args[1] == "fm" {
-		os.Exit(RunFileManager())
+		startDir := ""
+		if len(os.Args) >= 3 {
+			startDir = os.Args[2]
+		}
+		os.Exit(RunFileManager(startDir))
 		return
 	}
 
@@ -3202,9 +3206,13 @@ func (state *TermState) HandleToken(token TerminalToken) (bool, error) {
 		} else if t.Char == 12 { // Ctrl-L
 			state.ClearScreen()
 		} else if t.Char == 15 { // Ctrl-O - file manager
-			newDir := RunFileManagerInteractive(state.stdInFd, &state.oldState)
+			newDir := RunFileManagerInteractive(state.stdInFd, &state.oldState, "")
 			if newDir != "" {
-				os.Chdir(newDir)
+				cwd, cwdErr := os.Getwd()
+				if err := os.Chdir(newDir); err == nil && cwdErr == nil {
+					os.Setenv("OLDPWD", cwd)
+					os.Setenv("PWD", newDir)
+				}
 			}
 			// Refresh terminal size
 			cols, rows, sizeErr := term.GetSize(int(os.Stdout.Fd()))