[nongnu] elpa/zig-mode 8f59f86 089/104: Implement beginning/end-of-defun

[ELPA Syncer]

branch: elpa/zig-mode
commit 8f59f86133983975f1d25aefaf7378616c401a1d
Author: ventlark <ventlark@gmail.com>
Commit: ventlark <ventlark@gmail.com>

    Implement beginning/end-of-defun
    
    This allows us to use C-M-a and C-M-e to navigate by function blocks.
    Also includes test, const, and export blocks that contain a brace.
---
 zig-mode.el | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/zig-mode.el b/zig-mode.el
index db9a03b..4e0900b 100644
--- a/zig-mode.el
+++ b/zig-mode.el
@@ -264,6 +264,67 @@ If given a SOURCE, execute the CMD on it."
           ;; Skip backwards past whitespace and comment end delimiters.
           (/= 0 (skip-syntax-backward " >")))))
 
+(defun zig-in-str-or-cmnt () (nth 8 (syntax-ppss)))
+(defconst zig-top-item-beg-re
+  (concat "^"
+          (regexp-opt
+           '("const" "pub" "fn" "extern" "export" "test"))
+          "[[:space:]]+"
+          ".*{")
+  "Start of a Zig item.")
+
+(defun zig-beginning-of-defun (&optional arg)
+  "Move backward to the beginning of the current defun.
+
+With ARG, move backward multiple defuns.  Negative ARG means
+move forward.
+
+This is written mainly to be used as `beginning-of-defun-function' for Zig."
+  (interactive "p")
+  (let* ((arg (or arg 1))
+         (magnitude (abs arg))
+         (sign (if (< arg 0) -1 1)))
+    ;; If moving forward, don't find the defun we might currently be
+    ;; on.
+    (when (< sign 0)
+      (end-of-line))
+    (catch 'done
+      (dotimes (_ magnitude)
+        ;; Search until we find a match that is not in a string or comment.
+        (while (if (re-search-backward (concat "^\\(" zig-top-item-beg-re 
"\\)")
+                                       nil 'move sign)
+                   (zig-in-str-or-cmnt)
+                 ;; Did not find it.
+                 (throw 'done nil)))))
+    t)
+  (beginning-of-line))
+
+(defun zig-end-of-defun ()
+  "Move forward to the next end of defun.
+
+With argument, do it that many times.
+Negative argument -N means move back to Nth preceding end of defun.
+
+Assume that this is called after `beginning-of-defun'.  So point is
+at the beginning of the defun body.
+
+This is written mainly to be used as `end-of-defun-function' for Zig."
+  (interactive)
+  ;; Find the opening brace
+  (if (re-search-forward "[{]" nil t)
+      (progn
+        (goto-char (match-beginning 0))
+        ;; Go to the closing brace
+        (condition-case nil
+             (forward-sexp)
+          (scan-error
+           ;; The parentheses are unbalanced; instead of being unable
+           ;; to fontify, just jump to the end of the buffer
+           (goto-char (point-max))))
+        (end-of-line))
+    ;; There is no opening brace, so consider the whole buffer to be one 
"defun"
+    (goto-char (point-max))))
+
 (defun zig-mode-indent-line ()
   (interactive)
   ;; First, calculate the column that this line should be indented to.
@@ -428,6 +489,8 @@ If given a SOURCE, execute the CMD on it."
               (append zig-electric-indent-chars
                       (and (boundp 'electric-indent-chars)
                            electric-indent-chars)))
+  (setq-local beginning-of-defun-function 'zig-beginning-of-defun)
+  (setq-local end-of-defun-function 'zig-end-of-defun)
   (setq-local indent-line-function 'zig-mode-indent-line)
   (setq-local indent-tabs-mode nil)  ; Zig forbids tab characters.
   (setq-local syntax-propertize-function 'zig-syntax-propertize)