Support --check for batch mode diagnostics.

Mostly taken from the separate fennel-lint.fnl file.

README.md

@@ -39,6 +39,14 @@ Generally this involves somehow configuring this information:
 
 If you get it working in any other environments, I'd love to know! It would be great to have instructions on how to set up other editors!
 
+## Batch mode
+
+You can gather diagnostics without connecting your editor:
+
+```sh
+fennel-ls --check my-file.fnl f2.fnl # prints diagnostics for the files given
+```
+
 # Default Settings
 
 fennel-ls can be configured over LSP. Any setting that's not provided will be filled in with the defaults, which means that `{}` will be a valid configuration with default settings. You can provide different settings in the same shape as the default settings in order to override the defaults.

src/fennel-lint.fnl

@@ -1,26 +0,0 @@
-(local dispatch (require :fennel-ls.dispatch))
-(local state (require :fennel-ls.state))
-(local diagnostics (require :fennel-ls.diagnostics))
-(local {: view} (require :fennel))
-
-;; set up the state of fennel-ls into the `server` table
-(local server {})
-(dispatch.handle* server {:id 1
-                          :jsonrpc "2.0"
-                          :method "initialize"
-                          :params {:capabilities {}
-                                   :clientInfo {:name "Neovim" :version "0.7.2"}
-                                   :initializationOptions {}
-                                   :rootPath "."
-                                   :rootUri "file://."
-                                   :trace "off"
-                                   :workspaceFolders [{:name "."
-                                                       :uri "file://."}]}})
-
-;; open the file specified by (. arg 1) from the command line
-(local file (state.get-by-uri server (.. "file://" (. arg 1))))
-;; run diagnostics to populate file.diagnostics field
-(diagnostics.check server file)
-;; print the output
-(each [_ v (ipairs file.diagnostics)]
-  (print (view v)))

src/fennel-ls.fnl

@@ -1,5 +1,22 @@
 (local dispatch (require :fennel-ls.dispatch))
 (local json-rpc (require :fennel-ls.json-rpc))
+(local state (require :fennel-ls.state))
+(local diagnostics (require :fennel-ls.diagnostics))
+(local {: view} (require :fennel))
+
+(λ check [filename]
+  (let [server (doto {}
+                 (dispatch.handle* {:id 1
+                                    :jsonrpc "2.0"
+                                    :method "initialize"
+                                    :params {:capabilities {}
+                                             :clientInfo {:name "fennel-ls"}
+                                             :rootUri "file://"}}))
+        file (state.get-by-uri server (.. "file://" filename))]
+    (diagnostics.check server file)
+    (each [_ v (ipairs file.diagnostics)]
+      ;; perhaps nicer formatting in the future?
+      (print (view v)))))
 
 (λ main-loop [in out]
   (local send (partial json-rpc.write out))
@@ -9,8 +26,13 @@
       (dispatch.handle state send msg))))
 
 (λ main []
-  (main-loop
-    (io.input)
-    (io.output)))
+  (case arg
+    ["--check" & filenames] (each [_ filename (ipairs filenames)]
+                              (print "Checking" filename)
+                              (check filename))
+    (where (or ["--server"] [nil])) (main-loop (io.input)
+                                               (io.output))
+    _args (do (io.stderr:write "USAGE: fennel-ls [--check file] [--server]\n")
+              (os.exit 1))))
 
 (main)