Check for eca on PATH

Author: ericdallo

README.md

@@ -36,7 +36,9 @@ M-x package-install eca
 ## Quickstart
 
 1. Run `M-x eca` to start the eca process and initialize the workspace.
-  - eca-emacs will download `eca` automatically and cache it, or use `eca-custom-command` to start server.
+  - eca-emacs will check for `eca-custom-command`;
+  - if not set, will check for a `eca` on `$PATH`;
+  - if not found, will download `eca` automatically and cache it.
 2. The dedicated chat window `<eca-chat>` pops up.
 3. Type your prompt after the `> ` and press RET.
 4. Attach more context auto completing after the `@`.

eca.el

@@ -149,6 +149,8 @@ If not provided, download and start eca automatically."
 (defun eca--server-command ()
   "Return the command to start server."
   (or eca-custom-command
+      (when-let* ((command (executable-find "eca")))
+        (list command "server"))
       (list eca-server-install-path "server")))
 
 (defun eca--parse-header (s)