Editing

Open a directory to work on its files, or pass filenames to put them directly on the desktop:

thc-edit .
thc-edit src/Main.hs src/Library.hs

With no argument, the editor finds the nearest enclosing Cabal package, falling back to the current directory. A directory argument takes precedence. Opening a package also opens its .cabal file; with several package files, the editor prefers the directory namesake, then the first alphabetically. Explicit source files stay selected.

Files and directories

F3 opens the file dialog. Enter a name or wildcard filter, select a file and choose Open. Double-click a directory to browse into it, or a file to open it. The list shows the file's size and local modification time.

Ctrl+B, or Tools > File tree, toggles the Files pane. Expand directories to browse their contents and open files from the tree. Drag the divider to make room for long names; adjacent windows follow it. Unsaved filenames appear in red and return to normal after saving or undoing the change.

File > Change dir changes the working directory and refreshes Files without closing open buffers. Enter browses into the selected directory, Browse opens a typed path, and OK accepts the displayed directory.

Text and selection

Type to insert text. Hold Shift while moving to select it, or drag with the mouse. Ctrl+arrows moves by word. Edit > Select all selects the buffer. Copy, Cut and Paste are available in the Edit menu and on Ctrl+C/X/V; Ctrl+Insert, Shift+Delete and Shift+Insert provide the other familiar bindings.

Ctrl+Z undoes and Ctrl+Y redoes. Split views share text and undo history; each view keeps its own cursor and selection. UTF-8 text retains its line endings, including CRLF. Combining sequences and joined emoji move and delete as complete graphemes; your terminal or selected frontend supplies their appearance.

Syntax highlighting follows the filename. Haskell, C, C++, Cabal files and over 100 other languages use Skylighting's language definitions. New unnamed text buffers start with Haskell highlighting; unknown extensions use plain text.

The native window and browser use the system clipboard. Text terminals keep an editor-local clipboard and request a system clipboard write through OSC 52 on Copy and Cut. Whether that reaches your system clipboard depends on the terminal. Use the terminal's paste command for external text. See frontend controls for browser shortcut differences and clipboard permissions.

Search

Ctrl+F opens Find, Ctrl+R opens Replace, and Ctrl+L searches again. Search matches literal text and is case-sensitive. Replace changes one match at a time. Ctrl+G, or Search > Go to line, goes to a line number.

In the browser, Ctrl/Cmd+F opens Find and Ctrl/Cmd+G finds the next match. Shift+Ctrl/Cmd+G finds the previous match. Use the menu for Go to line there.

Windows

Use Window > Split vertically or Split horizontally to keep two parts of a file visible. A split is another view of the same file, so an edit or Undo in either window appears in both.

Drag a title to move a window, a frame edge to resize that side, or the bottom-right corner to resize both dimensions. Window > Tile arranges windows alongside one another; Cascade staggers them. F5 zooms the active window. During a move or resize, arrows move, Shift+arrows resize and Enter finishes. Escape restores all windows affected by the drag.

Touching edges stay together when you move a divider. Equal sides share the divider; a smaller window whose whole side touches the edge moves with it. Once that window reaches a desktop boundary, its outer edge stays there and further divider movement resizes it. The same rule carries a chain of touching windows. Partial overlaps stay independent, and a diagonal corner drag breaks the contact.

Windows touching a desktop edge grow with that edge when the desktop grows. Floating windows keep their position and size. Dragging a title preserves size while there is room, then shrinks the window against the desktop or dock boundary. Files and Messages remain the boundaries for adjacent windows.

F6 or Ctrl+Tab cycles windows. Shift+Ctrl+Tab reverses direction. Each editor and Messages window has a stable number: Alt+1 through Alt+9 activates it. On macOS, use Option for these numbered shortcuts.

Alt+Tab cycles the menu, Files, windows and Messages; Shift reverses it. Some operating systems reserve this shortcut. Click the destination or use the window shortcuts when the OS intercepts it.

Menus and dialogs

Press F10 to enter the menu bar, then use arrows or letter mnemonics. The status bar describes the highlighted action. Its key labels are clickable. On macOS, the native menu bar also provides Command shortcuts.

Tab and Shift+Tab cycle dialog controls. Enter accepts and Escape cancels. Ctrl or Alt plus a button's marked letter activates it. Dialogs also accept Alt+Tab for focus traversal. Mouse buttons activate when released over the button; releasing outside cancels the click.

Save, close and external changes

F2 saves. File > Save as writes under a new name and refuses to replace an existing destination. Alt+F3 closes the current window and Alt+X exits. Closing the last view of a changed file, or exiting with changed files, asks what to save. File > Exit ends the editor session. To leave the desktop running, detach and use thc-edit --resume later; Ctrl+] detaches from the terminal frontend. See sessions for the other frontends.

A title star means the buffer has unsaved edits. The branch badge's star means saved changes in Git; saving a buffer can clear one while setting the other.

The editor watches open files and expanded directories. A clean buffer reloads when the file changes on disk, retaining Undo. If the buffer also has edits, or the file was deleted, the editor keeps the versions and offers:

File > Disk changes reopens the conflict. Keep does not accept the new disk contents as a save baseline: the next Save still checks the conflict. Repeated observations of the same change do not repeatedly interrupt you. These checks also apply after Git operations and conversation edits.

WordStar keys

Select WordStar under Options > Preferences, or start with --wordstar.

Escape cancels a prefix. This is a useful subset of WordStar's commands.

See also Haskell tools, Git and hex editing.