Create rust-compile.el from existing code

For the time being `require' the new library from "rust-mode.el".
In the mid-term we should stop doing that, so that users can load
it if and only if they want to do so.

1 files changed, 83 insertions, 0 deletions

diff --git a/rust-compile.el b/rust-compile.el
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+;;; rust-compile.el --- Compile facilities           -*-lexical-binding: t-*-
+;;; Commentary:
+
+;; This library teaches `compilation-mode' about "rustc" output.
+
+;;; Code:
+
+(require 'compile)
+
+;;; _
+
+(defvar rustc-compilation-location
+  (let ((file "\\([^\n]+\\)")
+        (start-line "\\([0-9]+\\)")
+        (start-col "\\([0-9]+\\)"))
+    (concat "\\(" file ":" start-line ":" start-col "\\)")))
+
+(defvar rustc-compilation-regexps
+  (let ((re (concat "^\\(?:error\\|\\(warning\\)\\|\\(note\\)\\)[^\0]+?--> "
+                    rustc-compilation-location)))
+    (cons re '(4 5 6 (1 . 2) 3)))
+  "Specifications for matching errors in rustc invocations.
+See `compilation-error-regexp-alist' for help on their format.")
+
+(defvar rustc-colon-compilation-regexps
+  (let ((re (concat "^ *::: " rustc-compilation-location)))
+    (cons re '(2 3 4 0 1)))
+  "Specifications for matching `:::` hints in rustc invocations.
+See `compilation-error-regexp-alist' for help on their format.")
+
+(defvar rustc-refs-compilation-regexps
+  (let ((re "^\\([0-9]+\\)[[:space:]]*|"))
+    (cons re '(nil 1 nil 0 1)))
+  "Specifications for matching code references in rustc invocations.
+See `compilation-error-regexp-alist' for help on their format.")
+
+;; Match test run failures and panics during compilation as
+;; compilation warnings
+(defvar cargo-compilation-regexps
+  '("^\\s-+thread '[^']+' panicked at \\('[^']+', \\([^:]+\\):\\([0-9]+\\)\\)"
+    2 3 nil nil 1)
+  "Specifications for matching panics in cargo test invocations.
+See `compilation-error-regexp-alist' for help on their format.")
+
+(defun rustc-scroll-down-after-next-error ()
+  "In the new style error messages, the regular expression
+matches on the file name (which appears after `-->`), but the
+start of the error appears a few lines earlier.  This hook runs
+after `next-error' (\\[next-error]); it simply scrolls down a few lines in
+the compilation window until the top of the error is visible."
+  (save-selected-window
+    (when (eq major-mode 'rust-mode)
+      (select-window (get-buffer-window next-error-last-buffer 'visible))
+      (when (save-excursion
+              (beginning-of-line)
+              (looking-at " *-->"))
+        (let ((start-of-error
+               (save-excursion
+                 (beginning-of-line)
+                 (while (not (looking-at "^[a-z]+:\\|^[a-z]+\\[E[0-9]+\\]:"))
+                   (forward-line -1))
+                 (point))))
+          (set-window-start (selected-window) start-of-error))))))
+
+(eval-after-load 'compile
+  '(progn
+     (add-to-list 'compilation-error-regexp-alist-alist
+                  (cons 'rustc-refs rustc-refs-compilation-regexps))
+     (add-to-list 'compilation-error-regexp-alist 'rustc-refs)
+     (add-to-list 'compilation-error-regexp-alist-alist
+                  (cons 'rustc rustc-compilation-regexps))
+     (add-to-list 'compilation-error-regexp-alist 'rustc)
+     (add-to-list 'compilation-error-regexp-alist-alist
+                  (cons 'rustc-colon rustc-colon-compilation-regexps))
+     (add-to-list 'compilation-error-regexp-alist 'rustc-colon)
+     (add-to-list 'compilation-error-regexp-alist-alist
+                  (cons 'cargo cargo-compilation-regexps))
+     (add-to-list 'compilation-error-regexp-alist 'cargo)
+     (add-hook 'next-error-hook 'rustc-scroll-down-after-next-error)))
+
+;;; _
+(provide 'rust-compile)
+;;; rust-compile.el ends here