Update OR= to support unbound variables

apps/news/blog.arc

@@ -1,7 +1,10 @@
 ; A blog for news.arc
 ; For the standalone blog example by PG, see blog.arc from arc3.1
 
-(= postdir* (+ srvdir* "posts/")  blog-maxid* 0  posts* (table))
+(= postdir* (+ srvdir* "posts/"))
+
+(or= blog-maxid* 0
+     posts*      (table))
 
 (deftem post  id nil  by nil  title nil  text nil)
 

apps/news/news.arc

@@ -180,9 +180,9 @@
 (def author (u i) (is u i!by))
 
 
-(= stories* nil ranked-stories* nil comments* nil
-   items* (table) url->story* (table)
-   maxid* 0 initload* 15000)
+(or= stories* nil ranked-stories* nil comments* nil
+     items* (table) url->story* (table)
+     maxid* 0 initload* 15000)
 
 ; The dir expression yields stories in order of file creation time
 ; (because arc infile truncates), so could just rev the list instead of
@@ -233,7 +233,7 @@
 (def register-url (i url)
   (= (url->story* (canonical-url url)) i!id))
 
-(= stemmable-sites* (table))
+(or= stemmable-sites* (table))
 
 (def canonical-url (url)
   (if (stemmable-sites* (sitename url))
@@ -268,7 +268,7 @@
     (set i!dead)
     (save-item i)))
 
-(= kill-log* nil)
+(or= kill-log* nil)
 
 (def log-kill (i how)
   (push (list i!id how) kill-log*))
@@ -416,7 +416,7 @@
                   background-color: #" (hexrep (main-color user)) ";"
                   "}"))))
 
-(= pagefns* nil)
+(or= pagefns* nil)
 
 ; page top
 
@@ -573,7 +573,7 @@
            (newslog ip user ',name ,@parms)
            ,@body)))))
 
-(= newsop-names* nil)
+(or= newsop-names* nil)
 
 (mac newsop args
   `(do (pushnew ',(car args) newsop-names*)
@@ -1051,7 +1051,7 @@
 
 (= user-changetime* 120 editor-changetime* 1440)
 
-(= everchange* (table) noedit* (table))
+(or= everchange* (table) noedit* (table))
 
 (def canedit (user i)
   (or (admin user)
@@ -1685,7 +1685,7 @@
       (do (note-baditem user ip)
           (pr "No such item.")))))
 
-(= baditemreqs* (table) baditem-threshold* 1/100)
+(or= baditemreqs* (table) baditem-threshold* 1/100)
 
 ; Something looking at a lot of deleted items is probably the bad sort
 ; of crawler.  Throttle it for this server invocation.
@@ -1730,7 +1730,7 @@
            (mem 'commentable i!keys))))
 
 
-(= displayfn* (table))
+(or= displayfn* (table))
 
 (= (displayfn* 'story)   (fn (n i user here inlist)
                            (display-story n i user here)))
@@ -1773,7 +1773,7 @@
 
 (def editable-type (i) (fieldfn* i!type))
 
-(= fieldfn* (table))
+(or= fieldfn* (table))
 
 (= (fieldfn* 'story)
    (fn (user s)

arc.arc

@@ -954,6 +954,17 @@ See [[atomic]]."
   (= x 2 y 4)
   _)
 
+(mac or= args
+  `(do ,@(map [cons 'or-assign _] (pair args))))
+
+(mac or-assign (slot value)
+  `(atomic
+     ,(if (ssyntax slot)
+          `(or-assign ,(ssexpand slot) ,value)
+          (alist slot)
+          `(or ,slot (= ,slot ,value))
+        `(or (if (bound ',slot) ,slot) (= ,slot ,value)))))
+
 (def lastcons (xs)
 "Returns the absolute last link of list 'xs'. Save this value to efficiently
 append to 'xs'."
@@ -2750,11 +2761,6 @@ of 'x' by calling 'self'."
    (3 4)
    (4)))
 
-(mac or= (place expr)
-  (let (binds val setter) (setforms place)
-    `(atwiths ,binds
-       (or ,val (,setter ,expr)))))
-
 (defextend iso (x y) (isa x 'table)
   (and (isa x 'table)
        (isa y 'table)
@@ -2874,7 +2880,7 @@ of 'x' by calling 'self'."
 (def write (x (o port (stdout)))
   (swrite serialize.x port))
 
-(= hooks* (table))
+(or= hooks* (table))
 
 (def hook (name . args)
   (aif (hooks* name) (apply it args)))
@@ -2899,7 +2905,7 @@ Useful in higher-order functions, or to index into lists, strings, tables, etc."
   (map get.2 '((a b c) (1 2 3) (p q r)))
   (c 3 r))
 
-(= savers* (table))
+(or= savers* (table))
 
 (mac fromdisk (var file init load save)
   (w/uniq (gf gv)

lib/app.arc

@@ -30,7 +30,7 @@
 
 ; idea: a bidirectional table, so don't need two vars (and sets)
 
-(= cookie->user* (table) user->cookie* (table) logins* (table))
+(or= cookie->user* (table) user->cookie* (table) logins* (table))
 
 (def get-user (req)
 "Gets the user id string associated with 'req'.
@@ -258,7 +258,7 @@ Returns nil if no logged-in user."
                    (link "Try logging in now." "/")))))
     (single-input "New password: " 'p 20 "update" t)))
 
-(= good-logins* (queue) bad-logins* (queue))
+(or= good-logins* (queue) bad-logins* (queue))
 
 (def good-login (user pw ip)
   (let record (list (seconds) ip user)
@@ -279,7 +279,7 @@ Returns nil if no logged-in user."
    ;prepending this (stdin)= for backwards compatibility with previous hashes
    (+ "(stdin)= " ($.bytes->hex-string ($.sha512 ($.string->bytes/utf-8 str)))))
 
-(= dc-usernames* (table))
+(or= dc-usernames* (table))
 
 (def username-taken (user)
   (when (empty dc-usernames*)

lib/brackets.arc

@@ -1,5 +1,4 @@
 ; avoid redefinition warning
-($ (namespace-undefine-variable! (ac-global-name '%brackets)))
 
 (def -mbf-argsym (e)
   (and (begins string.e "_")
@@ -23,7 +22,7 @@
 ;   treats any symbols starting with '_' as args, ordered alphabetically
 ;     e.g. _1, _2, _3, or _a, _b, _c, etc.
 ;   treats __ as the rest arg
-(mac %brackets body
+(remac %brackets body
   (let args '__
     (each arg (dedup:sort > -mbf-argsyms.body)
       (pushnew arg args))

lib/declare.arc

@@ -1,6 +1,6 @@
 ; by [email protected]
 
-(= declare-fns* (table))
+(or= declare-fns* (table))
 
 (defs decl-idfn (old new args) new
       decl-bool (old new args) (no:no new))

lib/html.arc

@@ -28,7 +28,7 @@
    darkblue (color 0 0 120)
    )
 
-(= opmeths* (table))
+(or= opmeths* (table))
 
 (mac opmeth args
   `(opmeths* (list ,@args)))

lib/ppr.arc

@@ -1,8 +1,8 @@
-(= pprsyms* (fill-table (table) 
-                        '(quote "'" 
-                          quasiquote "`"
-                          unquote ","
-                          unquote-splicing ",@")))
+(or= pprsyms* (fill-table (table) 
+                          '(quote "'" 
+                            quasiquote "`"
+                            unquote ","
+                            unquote-splicing ",@")))
 
 (def sp ((o n 1))
   " Print a number of spaces. "
@@ -143,7 +143,7 @@
         (indent-block (nthcdr 2 xs) (+ col (len "(suite "))))
       (indent-block (cdr xs) (+ col (len "(suite "))))))
 
-(= indent-rules* 
+(or= indent-rules* 
    (fill-table (table)
      `(if      ,(indent-if (len "if"))
        aif     ,(indent-if (len "aif"))

lib/prompt.arc

@@ -99,7 +99,7 @@
         (fn () (map eval exprs)))
       (prompt-page user "Error: No application " app " for user " user))))
 
-(wipe repl-history*)
+(or= repl-history* nil)
 
 (defop repl req
   (if (admin (get-user req))

lib/srv.arc

@@ -26,12 +26,11 @@
 ; To adjust this while running, adjust the req-window* time, not
 ; req-limit*, because algorithm doesn't enforce decreases in the latter.
 
-  req-times* (table) 
   req-limit* 30 
   req-window* 10 ;10 
   dos-window* 2 ;2
 )
-
+(or= req-times* (table))
 
 (def serve ((o port 8080))
   (wipe quitsrv*)
@@ -65,8 +64,8 @@
 ; a thread to handle it. also arrange to kill that thread
 ; if it has not completed in threadlife* seconds.
 
-(= threadlife* 30  requests* 0  requests/ip* (table)
-   throttle-ips* (table)  ignore-ips* (table)  spurned* (table))
+(or= threadlife* 30  requests* 0  requests/ip* (table)
+     throttle-ips* (table)  ignore-ips* (table)  spurned* (table))
 
 (def accept-request-with-deadline (s)
   (with ((in out ip) (socket-accept s)
@@ -332,7 +331,7 @@
 
 ;; extending the server with new ops
 
-(= srvops* (table) redirector* (table) optimes* (table) opcounts* (table))
+(or= srvops* (table) redirector* (table) optimes* (table) opcounts* (table))
 
 (def save-optime (name elapsed)
   ; this is the place to put a/b testing
@@ -392,7 +391,7 @@ stdout, returns a url to redirect requests to after processing."
                                         it)))
     ""))
 
-(= fns* (table) fnids* nil timed-fnids* nil)
+(or= fns* (table) fnids* nil timed-fnids* nil)
 
 ; count on huge (expt 64 10) size of fnid space to avoid clashes
 
@@ -600,7 +599,7 @@ stdout, returns a url to redirect requests to after processing."
 
 ; only unique per server invocation
 
-(= unique-ids* (table))
+(or= unique-ids* (table))
 
 (def unique-id ((o len 8))
   (let id (sym (rand-string (max 5 len)))
@@ -661,7 +660,7 @@ stdout, returns a url to redirect requests to after processing."
 
 ; Background Threads
 
-(= bgthreads* (table) pending-bgthreads* nil)
+(or= bgthreads* (table) pending-bgthreads* nil)
 
 (def new-bgthread (id f sec)
   (aif (bgthreads* id) (break-thread it))

lib/tem.arc

@@ -1,6 +1,6 @@
 ($:require (only-in racket vector-map))
 
-(= templates* (table))
+(or= templates* (table))
 
 (mac deftem (tem . fields)
 "Defines a _template_, a table with defaults defined for various keys.