Babel: Toolchain support via :toolchain

README.md

@@ -431,7 +431,6 @@ If specific crate features are required then these can be specified
 with the `:features` argument. Note that if it is just a single feature
 then a string, instead of a list, will also be accepted:
 
-
 ```
 #+BEGIN_SRC rust :crates '((tokio . 1.0)) :features '((tokio . ("rt-multi-thread" "time")))
   extern crate tokio;
@@ -446,7 +445,34 @@ then a string, instead of a list, will also be accepted:
 #+END_SRC
 ```
 
-Supported org babel parameters:
+Similarly, to depend on local Rust crates, you can set the `:paths` argument:
+
+```
+#+BEGIN_SRC rust :crates '((foo . 1.0)) :paths '((foo . "/home/you/code/foo"))
+  use foo::Foo;
+
+  fn main() {
+    // Your code.
+  }
+#+END_SRC
+```
+
+You can also specify the `:toolchain`. Remember to quote the value!
+
+```
+#+begin_src rust :toolchain 'nightly
+fn main() {
+    let foo: String = vec!["a", "b", "c"].into_iter().intersperse(",").collect();
+
+    println!("{}", foo);
+}
+#+end_src
+
+#+RESULTS:
+: a,b,c
+```
+
+Other supported org babel parameters:
 
 Write to file `:results file :file ~/babel-output`
 

rustic-babel.el

@@ -50,11 +50,14 @@
 
 (defvar rustic-babel-spinner nil)
 
-(defun rustic-babel-eval (dir)
+(defun rustic-babel-eval (dir toolchain-kw)
   "Start a rust babel compilation process in directory DIR."
   (let* ((err-buff (get-buffer-create rustic-babel-compilation-buffer-name))
          (default-directory dir)
-         (params '("cargo" "build" "--quiet"))
+         (toolchain (cond ((eq toolchain-kw 'nightly) "+nightly")
+                          ((eq toolchain-kw 'beta) "+beta")
+                          (t "+stable")))
+         (params (list "cargo" toolchain "build" "--quiet"))
          (inhibit-read-only t))
     (rustic-compilation-setup-buffer err-buff dir 'rustic-compilation-mode)
     (when rustic-babel-display-compilation-buffer
@@ -64,9 +67,9 @@
      :buffer err-buff
      :command params
      :filter #'rustic-compilation-filter
-     :sentinel #'rustic-babel-build-sentinel)))
+     :sentinel (lambda (proc output) (rustic-babel-build-sentinel toolchain proc output)))))
 
-(defun rustic-babel-build-sentinel (proc _output)
+(defun rustic-babel-build-sentinel (toolchain proc _output)
   "Sentinel for rust babel compilation process PROC.
 If `rustic-babel-format-src-block' is t, format src-block after successful
 execution with rustfmt."
@@ -94,7 +97,7 @@ execution with rustfmt."
 
           ;; run project
           (let* ((err-buff (get-buffer-create rustic-babel-compilation-buffer-name))
-                 (params '("cargo" "run" "--quiet"))
+                 (params (list "cargo" toolchain "run" "--quiet"))
                  (inhibit-read-only t))
             (rustic-make-process
              :name rustic-babel-process-name
@@ -208,30 +211,33 @@ Otherwise create it with `rustic-babel-generate-project'."
           (put-text-property beg end 'project (make-symbol new))
           new)))))
 
-(defun crate-dependencies (name version features)
+(defun crate-dependencies (name version features path)
   "Generate a Cargo.toml [dependencies] entry for a crate given a version and features."
-  (let ((version-string (concat "version = \"" version "\""))
-        (features-string
-         (if features
-             (concat "features = [" (mapconcat (lambda (s) (concat "\"" s "\"")) features ", ") "]")
-           nil)))
-    (let ((toml-entry (string-join (remove nil (list version-string features-string)) ", ")))
-      (concat name " = {" toml-entry "}"))))
-
-(defun cargo-toml-dependencies (crate-versions crate-features)
+  (let* ((version-string (concat "version = \"" version "\""))
+         (features-string
+          (when features
+            (concat "features = [" (mapconcat (lambda (s) (concat "\"" s "\"")) features ", ") "]")))
+         (path-string
+          (when path
+            (concat "path = \"" path "\"")))
+         (toml-entry (string-join (remove nil (list version-string features-string path-string)) ", ")))
+    (concat name " = {" toml-entry "}")))
+
+(defun cargo-toml-dependencies (crate-versions crate-features crate-paths)
   "Generate the [dependencies] section of a Cargo.toml file given crates and their versions & features."
   (let ((dependencies ""))
     (dolist (crate-and-version crate-versions)
-      (let ((name (car crate-and-version))
-            (version (cdr crate-and-version)))
-        (let ((features (cdr (assoc name crate-features))))
-          (setq name (symbol-name name))
-          (when (numberp version)
-            (setq version (number-to-string version)))
-          (when (not (listp features))
-            (setq features (list features)))
-          (let ((cargo-toml-entry (crate-dependencies name version features)))
-            (setq dependencies (concat dependencies cargo-toml-entry "\n"))))))
+      (let* ((name (car crate-and-version))
+             (version (cdr crate-and-version))
+             (features (cdr (assoc name crate-features)))
+             (path (cdr (assoc name crate-paths))))
+        (setq name (symbol-name name))
+        (when (numberp version)
+          (setq version (number-to-string version)))
+        (when (not (listp features))
+          (setq features (list features)))
+        (let ((cargo-toml-entry (crate-dependencies name version features path)))
+          (setq dependencies (concat dependencies cargo-toml-entry "\n")))))
     (setq dependencies (concat "[dependencies]\n" dependencies))))
 
 (defun rustic-babel-cargo-toml (dir params)
@@ -240,8 +246,9 @@ Use org-babel parameter crates from PARAMS and add them to the project in
 directory DIR."
   (let ((crates (cdr (assq :crates params)))
         (features (cdr (assq :features params)))
+        (paths (cdr (assq :paths params)))
         (toml (expand-file-name "Cargo.toml" dir)))
-    (let ((dependencies (cargo-toml-dependencies crates features)))
+    (let ((dependencies (cargo-toml-dependencies crates features paths)))
       (make-directory (file-name-directory toml) t)
       (with-temp-file toml
         (condition-case nil
@@ -276,10 +283,11 @@ kill the running process."
           '(rustic-babel-spinner (":Executing " (:eval (spinner-print rustic-babel-spinner))))
           (spinner-start rustic-babel-spinner))
 
-        (let ((default-directory dir))
+        (let ((default-directory dir)
+              (toolchain (cdr (assq :toolchain params))))
           (write-region
            (concat "#![allow(non_snake_case)]\n" body) nil main nil 0)
-          (rustic-babel-eval dir)
+          (rustic-babel-eval dir toolchain)
           (setq rustic-babel-src-location
                 (set-marker (make-marker) (point) (current-buffer)))
           project)))))