ob-rust.el: Add `ob-rust', org-babel mode for rust

* contrib/lisp/ob-rust.el: Add ob-rust.el.  It has been adapted from
  ob-C.el and provides similar features:

  - `:var' assignments
  - `:uses' for module imports
  - `:externs' for crate imports
  - `:attributes' for setting attributes
  - Automatically wrapping code in `fn main() { [...] }' if necessary.
  - Only support for :results output
  - Not much in the way of error feedback

contrib/lisp/ob-rust.el

@@ -0,0 +1,207 @@
+;;; ob-rust.el --- org-babel functions for rust
+
+;; Author: Philip Munksgaard
+;; Keywords: literate programming, reproducible research
+;; Homepage: http://orgmode.org
+
+;;; Commentary:
+
+;; Org-Babel support for evaluating rust code.
+;;
+;; This is simply an adaptation of ob-C.el that instead targets rust code.
+;; Thanks to the original creators Eric Schulte and Thierry Banel
+;;
+;; Very limited implementation:
+;; - currently only support :results output
+;; - not much in the way of error feedback
+
+;;; Code:
+(eval-when-compile
+  (require 'cl))
+(require 'ob)
+(require 'cc-mode)
+
+(declare-function org-entry-get "org"
+		  (pom property &optional inherit literal-nil))
+
+
+(defvar org-babel-tangle-lang-exts)
+(add-to-list 'org-babel-tangle-lang-exts '("rust"))
+
+(defvar org-babel-default-header-args:rust '())
+
+(defvar org-babel-rust-compiler "rustc"
+  "Command used to compile a rust source code file into an
+executable.")
+
+(defun org-babel-expand-body:rust (body params)
+  (org-babel-rust-expand body params))
+
+(defun org-babel-execute:rust (body params)
+  "Execute a block of rust code with org-babel.
+This function is called by `org-babel-execute-src-block'."
+  (print body)
+  (princ params)
+  (let* ((tmp-src-file (org-babel-temp-file
+			"rust-src-"
+                        ".rs"))
+         (tmp-bin-file (org-babel-temp-file "rust-bin-" org-babel-exeext))
+         (cmdline (cdr (assoc :cmdline params)))
+         (flags (cdr (assoc :flags params)))
+         (full-body (org-babel-rust-expand body params))
+         (compile
+	  (progn
+	    (with-temp-file tmp-src-file (insert full-body))
+	    (org-babel-eval
+	     (format "%s -o %s %s %s"
+		     org-babel-rust-compiler
+		     (org-babel-process-file-name tmp-bin-file)
+		     (mapconcat 'identity
+				(if (listp flags) flags (list flags)) " ")
+		     (org-babel-process-file-name tmp-src-file)) ""))))
+    (let ((results
+           (org-babel-trim
+            (org-babel-eval
+             (concat tmp-bin-file (if cmdline (concat " " cmdline) "")) ""))))
+      (org-babel-reassemble-table
+       (org-babel-result-cond (cdr (assoc :result-params params))
+	 (org-babel-read results)
+         (let ((tmp-file (org-babel-temp-file "rust-")))
+           (with-temp-file tmp-file (insert results))
+           (org-babel-import-elisp-from-file tmp-file)))
+       (org-babel-pick-name
+        (cdr (assoc :colname-names params)) (cdr (assoc :colnames params)))
+       (org-babel-pick-name
+        (cdr (assoc :rowname-names params)) (cdr (assoc :rownames params)))))
+    ))
+
+(defun org-babel-rust-expand (body params)
+  "Expand a block of rust code with org-babel."
+  (print params)
+  (print body)
+  (let ((vars (mapcar #'cdr (org-babel-get-header params :var)))
+        (main-p (not (string= (cdr (assoc :main params)) "no")))
+        (uses (or (cdr (assoc :uses params))
+                      (org-babel-read (org-entry-get nil "uses" t))))
+        (externs (org-babel-read
+                  (or (cdr (assoc :externs params))
+                      (org-babel-read (org-entry-get nil "externs" t)))))
+        (attributes (org-babel-read
+                     (or (cdr (assoc :attributes params))
+                         (org-babel-read (org-entry-get nil "attributes" t))))))
+    (mapconcat 'identity
+	       (list
+		;; attributes
+		(mapconcat
+		 (lambda (attr) (format "#[%s]" attr))
+		 (if (listp attributes) attributes (list attributes)) "\n")
+		;; externs
+		(mapconcat
+		 (lambda (ext) (format "extern crate %s;" ext))
+		 (if (listp externs) externs (list externs)) "\n")
+                ;; uses
+		(mapconcat
+		 (lambda (use) (format "use %s;" use))
+		 (if (listp uses) uses (list uses)) "\n")
+		;; variables
+		(mapconcat 'org-babel-rust-var-to-rust vars "\n")
+		;; body
+		(if main-p
+		    (org-babel-rust-ensure-main-wrap body)
+		  body) "\n") "\n")))
+
+(defun org-babel-rust-ensure-main-wrap (body)
+  "Wrap BODY in a \"main\" function call if none exists."
+  (if (string-match "[ \t]*fn+[ \t\n\r]*main[ \t]*(.*)" body)
+      body
+    (format "fn main() {\n%s\n}\n" body)))
+
+(defun org-babel-prep-session:rust (session params)
+  "This function does nothing as rust is a compiled language with no
+support for sessions"
+  (error "rust is a compiled languages -- no support for sessions"))
+
+(defun org-babel-load-session:rust (session body params)
+  "This function does nothing as rust is a compiled language with no
+support for sessions"
+  (error "rust is a compiled languages -- no support for sessions"))
+
+;; helper functions
+
+(defun org-babel-rust-format-val (type val)
+  "Handle the FORMAT part of TYPE with the data from VAL."
+  (let ((format-data (cadr type)))
+    (if (stringp format-data)
+	(cons "" (format format-data val))
+      (funcall format-data val))))
+
+(defun org-babel-rust-val-to-rust-type (val)
+  "Determine the type of VAL.
+Return a list (TYPE-NAME FORMAT).  TYPE-NAME should be the name of the type.
+FORMAT can be either a format string or a function which is called with VAL."
+  (cond
+   ((integerp val) '("int" "%d"))
+   ((floatp val) '("f64" "%f"))
+   ((or (listp val) (vectorp val))
+    (lexical-let ((type (org-babel-rust-val-to-rust-list-type val)))
+      (list (concat "&'static [" (car type) "]")
+	    (lambda (val)
+	      (cons
+	       (format "[%d]%s"
+		       (length val)
+		       (car (org-babel-rust-format-val type (elt val 0))))
+	       (concat "&["
+		       (mapconcat (lambda (v)
+				    (cdr (org-babel-rust-format-val type v)))
+				  val
+				  ", ")
+		       "]"))))))
+   (t ;; treat unknown types as string
+    '("&'static str" (lambda (val)
+	       (let ((s (format "%s" val))) ;; convert to string for unknown types
+		 (cons (format "[%d]" (1+ (length s)))
+		       (concat "\"" s "\""))))))))
+
+(defun org-babel-rust-val-to-rust-list-type (val)
+  "Determine the rust array type of a VAL."
+  (let (type)
+    (mapc
+     #'(lambda (i)
+	 (let* ((tmp-type (org-babel-rust-val-to-rust-type i))
+		(type-name (car type))
+		(tmp-type-name (car tmp-type)))
+	   (when (and type (not (string= type-name tmp-type-name)))
+	     (if (and (member type-name '("int" "f64"))
+		      (member tmp-type-name '("int" "f64")))
+		 (setq tmp-type '("f64" "" "%f"))
+	       (error "Only homogeneous lists are supported by rust.  You can not mix %s and %s"
+		      type-name
+		      tmp-type-name)))
+	   (setq type tmp-type)))
+     val)
+    type))
+
+(defun org-babel-rust-var-to-rust (pair)
+  "Convert an elisp val into a string of rust code specifying a var
+of the same value."
+  ;; TODO list support
+  (let ((var (car pair))
+        (val (cdr pair)))
+    (when (symbolp val)
+      (setq val (symbol-name val))
+      (when (= (length val) 1)
+        (setq val (string-to-char val))))
+    (let* ((type-data (org-babel-rust-val-to-rust-type val))
+	   (type (car type-data))
+	   (formated (org-babel-rust-format-val type-data val))
+	   ;; (suffix (car formated))
+	   (data (cdr formated)))
+      (format "static %s: %s = %s;"
+              var
+	      type
+              ;suffix
+	      data))))
+
+(provide 'ob-rust)
+
+;;; ob-rust.el ends here