REPL: run visual commands in a terminal window

[ci skip]

docs/repl.md

@@ -65,6 +65,16 @@ The result is concatenated into a string and printed on stdout.
 
 This feature is only available in CIEL's REPL, not on the CIEL-USER package.
 
+Some programs are **visual** / interactive / ncurses-based, and need
+to be run in their own terminal window. CIEL recognizes a few (`vim`,
+`htop`, `man`…) and runs them in the first terminal emulator found on
+the system of `terminator`, `xterm`, `gnome-terminal`). See the
+`*visual-commands*` variable.
+
+> Note: this feature is experimental.
+
+> Note: we encourage our users to use Emacs rather than a terminal!
+
 We use the [Clesh](https://github.com/Neronus/clesh) library.
 
 See also [SHCL](https://github.com/bradleyjensen/shcl) for a more unholy union of posix-shell and Common Lisp.

repl-utils.lisp

@@ -46,3 +46,50 @@ bar:qux
     (when (= rl:+end+ rl:*point*)
       (format t "~c[1C" #\esc))
     (finish-output)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; Run visual / interactive / ncurses commands in their terminal window.
+;;;
+;;; How to guess a program is interactive?
+;;; We currently look from a hand-made list (à la Eshell).
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(defparameter *visual-commands*
+  '(;; "emacs -nw" ;; in eshell, concept of visual-subcommands.
+    "vim" "vi"
+    "nano"
+    "htop" "top"
+    "man" "less" "more"
+    "screen" "tmux"
+    "lynx" "links" "mutt" "pine" "tin" "elm" "ncftp" "ncdu"
+    "ranger"
+    ;; last but not least
+    "ciel-repl")
+  "List of visual/interactive/ncurses-based programs that will be run in their own terminal window.")
+
+(defparameter *visual-terminal-emulator-choices*
+  '("terminator" "x-terminal-emulator" "xterm" "gnome-terminal"))
+
+(defparameter *visual-terminal-switches* '("-e")
+  "Default options to the terminal. `-e' aka `--command'.")
+
+(defun find-terminal ()
+  "Return the first terminal emulator found on the system from the `*visual-terminal-emulator-choices*' list."
+  (loop for program in *visual-terminal-emulator-choices*
+     when (which:which program)
+     return program))
+
+(defun visual-command-p (text)
+  "The command TEXT starts by a known visual command, listed in `*visual-commands*'."
+  (let* ((cmd (string-left-trim "!" text)) ;; strip clesh syntax.
+         (first-word (first (str:words cmd))))
+    ;; This will be smarter. https://github.com/ruricolist/cmd/issues/10
+    (find first-word *visual-commands* :test #'equalp)))
+
+(defun run-visual-command (text)
+  "Run this text command into another terminal window."
+  (let ((cmd (string-left-trim "!" text)))
+    (uiop:launch-program `( ,(find-terminal)
+                             ;; quick way to flatten the list of switches:
+                             ,@*visual-terminal-switches*
+                             ,cmd))))

repl.lisp

@@ -458,8 +458,15 @@ strings to match candidates against (for example in the form \"package:sym\")."
         (sbcli::sbcli "" *prompt*))
     (when *hist-file* (sbcli::update-hist-file text))
     (cond
+      ;; Handle documentation lookup.
       ((str:ends-with-p " ?" text)
        (sbcli::symbol-documentation (last-nested-expr text)))
+
+      ;; Handle visual commands: run in their own terminal window.
+      ((visual-command-p text)
+       (run-visual-command text))
+
+      ;; Default: run the lisp command (with the lisp-critic and other add-ons).
       (t
        (sbcli::handle-input txt text)))
     (finish-output nil)