Add `--custom' option to `skribilo'.

* src/guile/skribilo.scm (skribilo-show-help): Update.
  (%options)[#\c]: New option.
  (%default-options)[:customs]: New option.
  (skribilo): Handle it.

* doc/user/compiler.skb (Skribilo Compiler)[Options]: Add.

* NEWS: Update.

3 files changed, 39 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index e5f1341..8395eb1 100644
--- a/NEWS
+++ b/NEWS
@@ -10,6 +10,7 @@ Copyright (C) 2005, 2006, 2007, 2008  Ludovic Courtès <ludo@gnu.org>
 
 ** Improved configure-time diagnostics
 ** `skribilo' now displays a call stack trace upon error when possible
+** New `--custom' compiler option
 
 * New in Skribilo 0.9.1
 
diff --git a/doc/user/compiler.skb b/doc/user/compiler.skb
index b208037..07fe724 100644
--- a/doc/user/compiler.skb
+++ b/doc/user/compiler.skb
@@ -80,6 +80,9 @@ conventions of Emacs' Outline mode (see ,(numref :text [Section] :ident
 	`(#\t "engine" ,[Use ,(tt "engine") as the engine, i.e., as
 the output format.  For details on engines and for a list of supported
 engines, see ,(numref :text [Chapter] :ident "engines").])
+	`(#\c "custom=value" ,[Set engine
+custom ,(tt [custom]) to ,(tt [value]), a constant.  See Section ,(ref
+:subsection "Engine Customs") for more information on customs.])
 	`("compat" "compat" ,[Use ,(tt "compat") as the compatibility
 mode.  This defaults to ,(tt [skribilo]).  Specifying ,(tt [skribe])
 enables the ,(ref :text [Skribe] :url *skribe-url*) compatibility mode,
diff --git a/src/guile/skribilo.scm b/src/guile/skribilo.scm
index d69ae32..f192838 100644
--- a/src/guile/skribilo.scm
+++ b/src/guile/skribilo.scm
@@ -41,6 +41,7 @@
   :use-module  (skribilo config)
 
   :autoload    (srfi srfi-1)     (alist-cons)
+  :use-module  (srfi srfi-13)
   :use-module  (srfi srfi-37)
   :use-module  (srfi srfi-39)
 
@@ -67,6 +68,7 @@ specified reader syntax, and produce its output using the specified engine.
   -R, --reader=READER    Use READER to parse the input file, e.g., `skribe'
                          (default) or `outline'.
   -t, --target=ENGINE    Use ENGINE as the output engine, e.g., `html'.
+  -c, --custom=C=VAL     Use VAL as the value of ENGINE's custom C.
   -o, --output=FILE      Write output to FILE.
       --compat=COMPAT    Use COMPAT as the compatibility layer, e.g., `skribe'.
 
@@ -166,6 +168,29 @@ Report bugs to <~a>.~%"
         (option '(#\t "target") #t #f
                 (lambda (opt name arg result)
                   (alist-cons :target arg result)))
+        (option '(#\c "custom") #t #f
+                (lambda (opt name arg result)
+                  (let ((=-pos (string-index arg #\=)))
+                    (if (not =-pos)
+                        (leave (_ "~a: missing value for custom") arg)
+                        (let ((custom (string-take arg =-pos))
+                              (value  (string-drop arg (+ =-pos 1))))
+                          (catch 'read-error
+                            (lambda ()
+                              (let ((custom (string->symbol custom))
+                                    (value
+                                     (with-input-from-string value read))
+                                    (result
+                                     (alist-delete :customs result eq?))
+                                    (customs
+                                     (assoc-ref result :customs)))
+                                (alist-cons
+                                 :customs
+                                 (alist-cons custom value customs)
+                                 result)))
+                            (lambda (key . args)
+                              (leave (_ "~a: invalid custom value")
+                                     value))))))))
         (option '(#\o "output") #t #f
                 (lambda (opt name arg result)
                   (if (assoc :output result)
@@ -242,6 +267,7 @@ Report bugs to <~a>.~%"
     (:source-path ".")
     (:image-path  ".")
     (:sui-path    ".")
+    (:customs)
     (:watched-symbols)))
 
 (define (parse-args args)
@@ -266,6 +292,7 @@ options."
 
 	 (reader-name       (string->symbol (assoc-ref options :reader)))
 	 (engine            (string->symbol (assoc-ref options :target)))
+         (customs           (assoc-ref options :customs))
          (input-file        (assoc-ref options :input))
 	 (output-file       (assoc-ref options :output))
 
@@ -316,6 +343,14 @@ options."
       ;; Load the user rc file (FIXME)
       ;;(load-rc)
 
+      (or (null? customs)
+          (let ((engine (lookup-engine engine)))
+            (for-each (lambda (custom+value)
+                        (let ((custom (car custom+value))
+                              (value  (cdr custom+value)))
+                          (engine-custom-set! engine custom value)))
+                      customs)))
+
       ;; Evaluate expressions passed as `--eval'.
       (for-each (lambda (expr)
                   (eval expr user-module))