Create rust-cargo.el from existing code

3 files changed, 105 insertions, 87 deletions

diff --git a/Makefile b/Makefile
index ded2945..aaa652c 100644
--- a/Makefile
+++ b/Makefile
@@ -10,6 +10,7 @@ EMACS ?= emacs
 EMACS_ARGS ?=
 
 ELS   = rust-mode.el
+ELS  += rust-cargo.el
 ELS  += rust-compile.el
 ELS  += rust-playpen.el
 ELS  += rust-rustfmt.el
diff --git a/rust-cargo.el b/rust-cargo.el
new file mode 100644
index 0000000..30ba611
--- /dev/null
+++ b/rust-cargo.el
@@ -0,0 +1,103 @@
+;;; rust-cargo.el --- Support for cargo                -*-lexical-binding: t-*-
+;;; Commentary:
+
+;; This library implements support for running `cargo'.
+
+;;; Code:
+
+(require 'json)
+
+;;; Options
+
+(defcustom rust-cargo-bin "cargo"
+  "Path to cargo executable."
+  :type 'string
+  :group 'rust-mode)
+
+(defcustom rust-always-locate-project-on-open nil
+  "Whether to run `cargo locate-project' every time `rust-mode' is activated."
+  :type 'boolean
+  :group 'rust-mode)
+
+;;; Buffer Project
+
+(defvar-local rust-buffer-project nil)
+
+(defun rust-buffer-project ()
+  "Get project root if possible."
+  (with-temp-buffer
+    (let ((ret (call-process rust-cargo-bin nil t nil "locate-project")))
+      (when (/= ret 0)
+        (error "`cargo locate-project' returned %s status: %s" ret (buffer-string)))
+      (goto-char 0)
+      (let ((output (json-read)))
+        (cdr (assoc-string "root" output))))))
+
+(defun rust-update-buffer-project ()
+  (setq-local rust-buffer-project (rust-buffer-project)))
+
+(defun rust-maybe-initialize-buffer-project ()
+  (setq-local rust-buffer-project nil)
+  (when rust-always-locate-project-on-open
+    (rust-update-buffer-project)))
+
+(add-hook 'rust-mode-hook 'rust-maybe-initialize-buffer-project)
+
+;;; Internal
+
+(defun rust--compile (format-string &rest args)
+  (when (null rust-buffer-project)
+    (rust-update-buffer-project))
+  (let ((default-directory
+          (or (and rust-buffer-project
+                   (file-name-directory rust-buffer-project))
+              default-directory)))
+    (compile (apply #'format format-string args))))
+
+;;; Commands
+
+(defun rust-check ()
+  "Compile using `cargo check`"
+  (interactive)
+  (rust--compile "%s check" rust-cargo-bin))
+
+(defun rust-compile ()
+  "Compile using `cargo build`"
+  (interactive)
+  (rust--compile "%s build" rust-cargo-bin))
+
+(defun rust-compile-release ()
+  "Compile using `cargo build --release`"
+  (interactive)
+  (rust--compile "%s build --release" rust-cargo-bin))
+
+(defun rust-run ()
+  "Run using `cargo run`"
+  (interactive)
+  (rust--compile "%s run" rust-cargo-bin))
+
+(defun rust-run-release ()
+  "Run using `cargo run --release`"
+  (interactive)
+  (rust--compile "%s run --release" rust-cargo-bin))
+
+(defun rust-test ()
+  "Test using `cargo test`"
+  (interactive)
+  (rust--compile "%s test" rust-cargo-bin))
+
+(defun rust-run-clippy ()
+  "Run `cargo clippy'."
+  (interactive)
+  (when (null rust-buffer-project)
+    (rust-update-buffer-project))
+  (let* ((args (list rust-cargo-bin "clippy"
+                     (concat "--manifest-path=" rust-buffer-project)))
+         ;; set `compile-command' temporarily so `compile' doesn't
+         ;; clobber the existing value
+         (compile-command (mapconcat #'shell-quote-argument args " ")))
+    (rust--compile compile-command)))
+
+;;; _
+(provide 'rust-cargo)
+;;; rust-cargo.el ends here
diff --git a/rust-mode.el b/rust-mode.el
index 0b1f5d1..d4d61d7 100644
--- a/rust-mode.el
+++ b/rust-mode.el
@@ -17,16 +17,12 @@
 
 (eval-when-compile (require 'rx))
 
-(require 'json)
 (require 'thingatpt)
 
 (defvar electric-pair-inhibit-predicate)
 (defvar electric-pair-skip-self)
 (defvar electric-indent-chars)
 
-(defvar rust-buffer-project nil)
-(make-variable-buffer-local 'rust-buffer-project)
-
 ;;; Customization
 
 (defgroup rust-mode nil
@@ -59,16 +55,6 @@ When nil, `where' will be aligned with `fn' or `trait'."
   :safe #'booleanp
   :group 'rust-mode)
 
-(defcustom rust-cargo-bin "cargo"
-  "Path to cargo executable."
-  :type 'string
-  :group 'rust-mode)
-
-(defcustom rust-always-locate-project-on-open nil
-  "Whether to run `cargo locate-project' every time `rust-mode' is activated."
-  :type 'boolean
-  :group 'rust-mode)
-
 (defcustom rust-indent-return-type-to-arguments t
   "Indent a line starting with the `->' (RArrow) following a function, aligning
 to the function arguments.  When nil, `->' will be indented one level."
@@ -266,11 +252,7 @@ Use idomenu (imenu with `ido-mode') for best mileage.")
 
   (add-hook 'before-save-hook 'rust-before-save-hook nil t)
   (add-hook 'after-save-hook 'rust-after-save-hook nil t)
-
-  (setq-local rust-buffer-project nil)
-
-  (when rust-always-locate-project-on-open
-    (rust-update-buffer-project)))
+  )
 
 ;;;###autoload
 (add-to-list 'auto-mode-alist '("\\.rs\\'" . rust-mode))
@@ -1569,45 +1551,6 @@ This is written mainly to be used as `end-of-defun-function' for Rust."
     ;; There is no opening brace, so consider the whole buffer to be one "defun"
     (goto-char (point-max))))
 
-(defun rust--compile (format-string &rest args)
-  (when (null rust-buffer-project)
-    (rust-update-buffer-project))
-  (let ((default-directory
-          (or (and rust-buffer-project
-                   (file-name-directory rust-buffer-project))
-              default-directory)))
-    (compile (apply #'format format-string args))))
-
-(defun rust-check ()
-  "Compile using `cargo check`"
-  (interactive)
-  (rust--compile "%s check" rust-cargo-bin))
-
-(defun rust-compile ()
-  "Compile using `cargo build`"
-  (interactive)
-  (rust--compile "%s build" rust-cargo-bin))
-
-(defun rust-compile-release ()
-  "Compile using `cargo build --release`"
-  (interactive)
-  (rust--compile "%s build --release" rust-cargo-bin))
-
-(defun rust-run ()
-  "Run using `cargo run`"
-  (interactive)
-  (rust--compile "%s run" rust-cargo-bin))
-
-(defun rust-run-release ()
-  "Run using `cargo run --release`"
-  (interactive)
-  (rust--compile "%s run --release" rust-cargo-bin))
-
-(defun rust-test ()
-  "Test using `cargo test`"
-  (interactive)
-  (rust--compile "%s test" rust-cargo-bin))
-
 ;;; Secondary Commands
 
 (defun rust-promote-module-into-dir ()
@@ -1632,35 +1575,6 @@ visit the new file."
           (rename-file filename new-name 1)
           (set-visited-file-name new-name))))))
 
-(defun rust-run-clippy ()
-  "Run `cargo clippy'."
-  (interactive)
-  (when (null rust-buffer-project)
-    (rust-update-buffer-project))
-  (let* ((args (list rust-cargo-bin "clippy"
-                     (concat "--manifest-path=" rust-buffer-project)))
-         ;; set `compile-command' temporarily so `compile' doesn't
-         ;; clobber the existing value
-         (compile-command (mapconcat #'shell-quote-argument args " ")))
-    (rust--compile compile-command)))
-
-;;; Utilities
-
-(defun rust-update-buffer-project ()
-  (setq-local rust-buffer-project (rust-buffer-project)))
-
-(defun rust-buffer-project ()
-  "Get project root if possible."
-  (with-temp-buffer
-    (let ((ret (call-process rust-cargo-bin nil t nil "locate-project")))
-      (when (/= ret 0)
-        (error "`cargo locate-project' returned %s status: %s" ret (buffer-string)))
-      (goto-char 0)
-      (let ((output (json-read)))
-        (cdr (assoc-string "root" output))))))
-
-;;; Secondary Commands
-
 (defun rust-insert-dbg ()
   "Insert the dbg! macro."
   (cond ((region-active-p)