1 files changed, 68 insertions, 54 deletions

diff --git a/src/guile/skribilo/package/eq/lout.scm b/src/guile/skribilo/package/eq/lout.scm
index 561e4cb..c487b85 100644
--- a/src/guile/skribilo/package/eq/lout.scm
+++ b/src/guile/skribilo/package/eq/lout.scm
@@ -15,7 +15,7 @@
 ;;;
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with this program; if not, write to the Free Software
-;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 ;;; USA.
 
 (define-module (skribilo package eq lout)
@@ -26,7 +26,7 @@
   :use-module (skribilo engine)
   :use-module (skribilo lib)
   :use-module (skribilo utils syntax)
-  :use-module (skribilo skribe utils) ;; `the-options', etc.
+  :use-module (skribilo utils keywords) ;; `the-options', etc.
   :use-module (ice-9 optargs))
 
 (fluid-set! current-reader %skribilo-module-reader)
@@ -53,64 +53,78 @@
 
 
 (markup-writer 'eq (find-engine 'lout)
-   :before "{ @Eq { "
+   :options '(:inline?)
+   :before "{ "
    :action (lambda (node engine)
-	      (let ((eq (markup-body node)))
-		 ;(fprint (current-error-port) "eq=" eq)
-		 (output eq engine)))
+	     (display (if (markup-option node :inline?)
+			  "@E { "
+			  "@Eq { "))
+	     (let ((eq (markup-body node)))
+	       ;;(fprint (current-error-port) "eq=" eq)
+	       (output eq engine)))
    :after  " } }")
 
 
-;;
-;; `+' and `-' have lower precedence than `*', `/', `=', etc., so their
-;; operands do not need to be enclosed in braces.
-;;
-
-(markup-writer 'eq:+ (find-engine 'lout)
-   :action (lambda (node engine)
-	      (let loop ((operands (markup-body node)))
-		 (if (null? operands)
-		     #t
-		     (begin
-		       ;; no braces
-		       (output (car operands) engine)
-		       (if (pair? (cdr operands))
-			   (display " + "))
-		       (loop (cdr operands)))))))
-
-(markup-writer 'eq:- (find-engine 'lout)
-   :action (lambda (node engine)
-	      (let loop ((operands (markup-body node)))
-		 (if (null? operands)
-		     #t
-		     (begin
-		       ;; no braces
-		       (output (car operands) engine)
-		       (if (pair? (cdr operands))
-			   (display " - "))
-		       (loop (cdr operands)))))))
-
-(define-macro (simple-lout-markup-writer sym . lout-name)
-  `(markup-writer ',(symbol-append 'eq: sym)
-		  (find-engine 'lout)
-      :action (lambda (node engine)
-		(let loop ((operands (markup-body node)))
-		  (if (null? operands)
-		      #t
-		      (begin
-			(display " { ")
-			(output (car operands) engine)
-			(display " }")
-			(if (pair? (cdr operands))
-			    (display ,(string-append " "
-						     (if (null? lout-name)
-							 (symbol->string sym)
-							 (car lout-name))
-						     " ")))
-			(loop (cdr operands))))))))
 
+(define-macro (simple-lout-markup-writer sym . args)
+  (let* ((lout-name (if (null? args)
+			(symbol->string sym)
+			(car args)))
+	 (parentheses? (if (or (null? args) (null? (cdr args)))
+			   #t
+			   (cadr args)))
+	 (precedence (operator-precedence sym))
+
+	 ;; Note: We could use `pmatrix' here but it precludes line-breaking
+	 ;; within equations.
+	 (open-par `(if need-paren? "{ @VScale ( }" ""))
+	 (close-par `(if need-paren? "{ @VScale ) }" "")))
+
+    `(markup-writer ',(symbol-append 'eq: sym)
+		    (find-engine 'lout)
+		    :action (lambda (node engine)
+			      (let loop ((operands (markup-body node)))
+				(if (null? operands)
+				    #t
+				    (let* ((op (car operands))
+					   (eq-op? (equation-markup? op))
+					   (need-paren?
+					    (and eq-op?
+						 (< (operator-precedence
+						     (equation-markup-name->operator
+						      (markup-markup op)))
+						    ,precedence)))
+					   (column (port-column
+						    (current-output-port))))
+
+				      ;; Work around Lout's limitations...
+				      (if (> column 1000) (display "\n"))
+
+				      (display (string-append " { "
+							      ,(if parentheses?
+								   open-par
+								   "")))
+				      (output op engine)
+				      (display (string-append ,(if parentheses?
+								   close-par
+								   "")
+							      " }"))
+				      (if (pair? (cdr operands))
+					  (display ,(string-append " "
+								   lout-name
+								   " ")))
+				      (loop (cdr operands)))))))))
+
+
+;; `+' and `*' have higher precedence than `-', `/', `=', etc., so their
+;; operands do not need to be enclosed in parentheses.  OTOH, since we use a
+;; horizontal bar of `/', we don't need to parenthesize its arguments.
+
+
+(simple-lout-markup-writer +)
 (simple-lout-markup-writer * "times")
-(simple-lout-markup-writer / "over")
+(simple-lout-markup-writer - "-")
+(simple-lout-markup-writer / "over" #f)
 (simple-lout-markup-writer =)
 (simple-lout-markup-writer <)
 (simple-lout-markup-writer >)