Added flymake backend

README.md

@@ -31,6 +31,18 @@ This minor mode is highly recommended -- Carp's type errors are much easier to u
  (flycheck-mode 1)))
 ```
 
+## Flymake
+
+as an alternative to using Flycheck this uses Flymake removing the 3rd
+party dependency.
+
+```
+(require 'carp-flymake)
+
+(add-hook 'carp-mode-hook (lambda ()
+ (carp-setup-flymake-backend)
+ (flymake-mode 1)))
+```
 
 
 ## License

carp-flymake.el

@@ -0,0 +1,80 @@
+;;; carp-flymake.el --- A carp Flymake backend -*- lexical-binding: t; -*-
+;;; Commentary: Flymake backend using carp's --check command.
+;;; Code:
+(require 'flymake)
+
+(defvar-local carp--flymake-proc nil
+ "Variable storing the currently active flymake process running the carp checker.
+This is used to determine if the current diagnostics are out of date.")
+
+;;;###autoload
+(defun carp-flymake (report-fn &rest _args)
+ "Flymake backend for Carp syntax check.
+REPORT-FN is Flymake’s callback function."
+ ;; If the carp compiler is not installed signal an error
+ (unless (executable-find "carp")
+ (error "Cannot find a suitable version of the carp compiler"))
+ ;; If there is already a check runnning kill it
+ (when (process-live-p carp--flymake-proc)
+ (kill-process carp--flymake-proc))
+
+ ;; Save the current buffer, the narrowing restriction, remove any
+ ;; narrowing restriction.
+ ;;
+ (let ((source (current-buffer)))
+ (save-restriction
+ (widen)
+ ;; Reset the `carp--flymake-proc' process to a new process
+ ;; calling the carp tool.
+ ;;
+ (setq carp--flymake-proc
+ (make-process
+ :name "carp-flymake" :noquery t :connection-type 'pipe
+ ;; Make output go to a temporary buffer.
+ :buffer (generate-new-buffer " *carp-flymake*")
+ :command (list "carp" "--check" (buffer-file-name source))
+ :sentinel
+ (lambda (proc _event)
+ ;; Check that the process has indeed exited, as it might
+ ;; be simply suspended.
+ (when (memq (process-status proc) '(exit signal))
+ (unwind-protect
+ ;; Only proceed if `proc' is the same as
+ ;; `carp--flymake-proc', which indicates that
+ ;; `proc' is not an obsolete process.
+ ;;
+ (if (with-current-buffer source (eq proc carp--flymake-proc))
+ (with-current-buffer (process-buffer proc)
+ (goto-char (point-min))
+ ;; Parse the output buffer for diagnostic's
+ ;; messages and locations, collect them in a list
+ ;; of objects, and call `report-fn'.
+
+ (cl-loop
+ while (search-forward-regexp
+ "^\\(?:.*.carp\\|-\\):\\([0-9]+\\):\\(.*\\)$"
+ nil t)
+ for msg = (match-string 2)
+ for (beg . end) = (flymake-diag-region
+ source
+ (string-to-number (match-string 1)))
+ for type = :error
+ collect (flymake-make-diagnostic source
+ beg
+ end
+ type
+ msg)
+ into diags
+ finally (funcall report-fn diags)))
+ (flymake-log :warning "Canceling obsolete check %s"
+ proc))
+ ;; Cleanup the temporary buffer used to hold the
+ ;; check's output.
+ (kill-buffer (process-buffer proc))))))))))
+
+(defun carp-setup-flymake-backend ()
+ "Add the flymake-backend to the `flymake-diagnostic-functions'."
+ (add-hook 'flymake-diagnostic-functions 'carp-flymake nil t))
+
+(provide 'carp-flymake)
+;;; carp-flymake.el ends here