bulk: add PoC of vim-like modular editor

1 files changed, 67 insertions, 0 deletions

diff --git a/lib/terminal.mli b/lib/terminal.mli
new file mode 100644
index 0000000..0fd11ed
--- /dev/null
+++ b/lib/terminal.mli
@@ -0,0 +1,67 @@
+(** A module to simplify communication with the underlying terminal
+    emulator. *)
+
+open Base
+open Unix
+
+type terminal_size = int * int
+(** Size of the terminal window. *)
+
+type state = {
+  tio : terminal_io;  (** Status flags for the terminal window *)
+  size : terminal_size;  (** Size of the terminal window *)
+}
+(** Global state of the terminal window. *)
+
+val get_char : unit -> char option
+(** Non-blocking request for a keypress.
+    Use {!val:Terminal.char_stream} for an infinite sequence of input
+    bytes.
+
+    @return A [char] if a key was pressed, nothing otherwise. *)
+
+val char_stream : char option Sequence.t
+(** The infinite stream of input bytes from stdin.
+    Returns [None] if no key was pressed; this is to be able to
+    interpret the absense of a keypress as an action. *)
+
+val write_seq : char Sequence.t -> unit
+(** Write a sequence of strings to standard output.
+
+    @param seq The sequence of strings to output. *)
+
+val restore_screen : unit -> unit
+(** Clear screen and show cursor. Meant to be called on exit. *)
+
+val redraw : char Sequence.t Sequence.t -> int * int -> unit
+(** Redraw the screen, using the provided sequence of lines.
+
+    @param seq A sequence of lines.
+    @param cur Cursor position. *)
+
+val get_state : unit -> state
+(** Get current state for the terminal window *)
+
+val size : unit -> int * int
+(** Compute the current size of the terminal.
+
+    This is done by moving the cursor to the far bottom right position
+    and querying for the cursor position using the appropriate escape
+    sequences.
+
+    @return size of the terminal window in terms of character rows and columns. *)
+
+val enable_raw_mode : terminal_io -> unit -> unit
+(** Turn on raw mode by overriding the correct terminal flags.
+    This is done according to [man 3 termios].
+
+    @param tio The current status of the terminal for [stdin]. *)
+
+val restore_status : terminal_io -> unit -> unit
+(** Override the terminal status.
+
+    @param tio The new terminal status for [stdin]. *)
+
+val init : unit -> state
+(** Turns on raw mode and makes sure to restore the previous terminal
+    status on exit. *)