Merge pull request #1892 from rgrinberg/syntax-highlight-ielm

lang/emacs-lisp: add syntax highlighting to ielm buffers

modules/lang/emacs-lisp/config.el

@@ -90,6 +90,26 @@ This marks a foldable marker for `outline-minor-mode' in elisp buffers.")
           "f" #'find-function
           "v" #'find-variable)))
 
+;; Adapted from http://www.modernemacs.com/post/comint-highlighting/
+(add-hook! 'ielm-mode-hook
+  (defun +emacs-lisp-init-syntax-highlighting-h ()
+    (font-lock-add-keywords
+     nil (cl-loop for (matcher . match-highlights)
+                  in (append lisp-el-font-lock-keywords-2 lisp-cl-font-lock-keywords-2)
+                  collect
+                  `((lambda (limit)
+                      (and ,(if (symbolp matcher)
+                                `(,matcher limit)
+                              `(re-search-forward ,matcher limit t))
+                           ;; Only highlight matches after the prompt
+                           (> (match-beginning 0) (car comint-last-prompt))
+                           ;; Make sure we're not in a comment or string
+                           (let ((state (sp--syntax-ppss)))
+                             (not (or (nth 3 state)
+                                      (nth 4 state))))))
+                    ,@match-highlights))))))
+
+
 ;;
 ;;; Packages