X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=scm%2Flily-library.scm;h=5b990e76040d762841280c36d041e6e2c7361b22;hb=86713eefa608f7dc738420ce0225c2a92c4539b2;hp=f772d0527e931efa53cdf0917fcf359012e911bb;hpb=24d7a2abc788061a4f7a81ee3c2a9f330ddca93f;p=lilypond.git

diff --git a/scm/lily-library.scm b/scm/lily-library.scm
index f772d0527e..5b990e7604 100644
--- a/scm/lily-library.scm
+++ b/scm/lily-library.scm
@@ -1,10 +1,23 @@
+;;;; This file is part of LilyPond, the GNU music typesetter.
 ;;;;
-;;;; lily-library.scm -- utilities
-;;;;
-;;;;  source file of the GNU LilyPond music typesetter
-;;;; 
-;;;; (c) 1998--2007 Jan Nieuwenhuizen <janneke@gnu.org>
+;;;; Copyright (C) 1998--2011 Jan Nieuwenhuizen <janneke@gnu.org>
 ;;;; Han-Wen Nienhuys <hanwen@xs4all.nl>
+;;;;
+;;;; LilyPond is free software: you can redistribute it and/or modify
+;;;; it under the terms of the GNU General Public License as published by
+;;;; the Free Software Foundation, either version 3 of the License, or
+;;;; (at your option) any later version.
+;;;;
+;;;; LilyPond is distributed in the hope that it will be useful,
+;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;;; GNU General Public License for more details.
+;;;;
+;;;; You should have received a copy of the GNU General Public License
+;;;; along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
+
+; for take, drop, take-while, list-index, and find-tail:
+(use-modules (srfi srfi-1))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; constants.
@@ -44,11 +57,24 @@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; moments
 
-(define-public ZERO-MOMENT (ly:make-moment 0 1)) 
+(define-public ZERO-MOMENT (ly:make-moment 0 1))
 
 (define-public (moment-min a b)
   (if (ly:moment<? a b) a b))
 
+(define-public (moment<=? a b)
+  (or (equal? a b)
+      (ly:moment<? a b)))
+
+(define-public (fraction->moment fraction)
+  (if (null? fraction)
+      ZERO-MOMENT
+      (ly:make-moment (car fraction) (cdr fraction))))
+
+(define-public (moment->fraction moment)
+  (cons (ly:moment-main-numerator moment)
+        (ly:moment-main-denominator moment)))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; arithmetic
 (define-public (average x . lst)
@@ -57,13 +83,27 @@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; parser <-> output hooks.
 
-		
+(define-public (collect-bookpart-for-book parser book-part)
+  "Toplevel book-part handler."
+  (define (add-bookpart book-part)
+    (ly:parser-define!
+       parser 'toplevel-bookparts
+       (cons book-part (ly:parser-lookup parser 'toplevel-bookparts))))
+  ;; If toplevel scores have been found before this \bookpart,
+  ;; add them first to a dedicated bookpart
+  (if (pair? (ly:parser-lookup parser 'toplevel-scores))
+      (begin
+	(add-bookpart (ly:make-book-part
+		       (ly:parser-lookup parser 'toplevel-scores)))
+	(ly:parser-define! parser 'toplevel-scores (list))))
+  (add-bookpart book-part))
+
 (define-public (collect-scores-for-book parser score)
   (ly:parser-define!
    parser 'toplevel-scores
    (cons score (ly:parser-lookup parser 'toplevel-scores))))
 
-(define (collect-music-aux score-handler parser music)
+(define-public (collect-music-aux score-handler parser music)
   (define (music-property symbol)
     (let ((value (ly:music-property music symbol)))
       (if (not (null? value))
@@ -91,49 +131,83 @@
 	 (score-handler (scorify-music music parser)))))
 
 (define-public (collect-music-for-book parser music)
-  "Top-level music handler"
+  "Top-level music handler."
   (collect-music-aux (lambda (score)
 		       (collect-scores-for-book parser score))
                      parser
 		     music))
 
 (define-public (collect-book-music-for-book parser book music)
-  "Book music handler"
+  "Book music handler."
   (collect-music-aux (lambda (score)
 		       (ly:book-add-score! book score))
                      parser
 		     music))
 
 (define-public (scorify-music music parser)
-  "Preprocess MUSIC."
-  
+  "Preprocess @var{music}."
+
   (for-each (lambda (func)
 	      (set! music (func music parser)))
 	    toplevel-music-functions)
 
   (ly:make-score music))
 
-(define (print-book-with parser book process-procedure)
-  (let*
-      ((paper (ly:parser-lookup parser '$defaultpaper))
-       (layout (ly:parser-lookup parser '$defaultlayout))
-       (count (ly:parser-lookup parser 'output-count))
-       (base (ly:parser-output-name parser))
-       (output-suffix (ly:parser-lookup parser 'output-suffix)) )
 
+(define (get-current-filename parser)
+  "return any suffix value for output filename allowing for settings by
+calls to bookOutputName function"
+  (let ((book-filename (ly:parser-lookup parser 'book-filename)))
+    (if (not book-filename)
+	(ly:parser-output-name parser)
+	book-filename)))
+
+(define (get-current-suffix parser)
+  "return any suffix value for output filename allowing for settings by calls to
+bookoutput function"
+  (let ((book-output-suffix (ly:parser-lookup parser 'book-output-suffix)))
+    (if (not (string? book-output-suffix))
+	(ly:parser-lookup parser 'output-suffix)
+	book-output-suffix)))
+
+(define-public current-outfile-name #f)  ; for use by regression tests
+
+(define (get-outfile-name parser)
+  "return current filename for generating backend output files"
+  ;; user can now override the base file name, so we have to use
+  ;; the file-name concatenated with any potential output-suffix value
+  ;; as the key to out internal a-list
+  (let* ((base-name (get-current-filename parser))
+	 (output-suffix (get-current-suffix parser))
+	 (alist-key (format #f "~a~a" base-name output-suffix))
+	 (counter-alist (ly:parser-lookup parser 'counter-alist))
+	 (output-count (assoc-get alist-key counter-alist 0))
+	 (result base-name))
+    ;; Allow all ASCII alphanumerics, including accents
     (if (string? output-suffix)
-	(set! base (format "~a-~a" base (string-regexp-substitute
-					   "[^a-zA-Z0-9-]" "_" output-suffix))))
-
-    ;; must be careful: output-count is under user control.
-    (if (not (integer? count))
-	(set! count 0))
+        (set! result
+              (format #f "~a-~a"
+                      result
+                      (string-regexp-substitute
+                       "[^-[:alnum:]]"
+                       "_"
+                       output-suffix))))
+
+    ;; assoc-get call will always have returned a number
+    (if (> output-count 0)
+        (set! result (format #f "~a-~a" result output-count)))
+
+    (ly:parser-define!
+     parser 'counter-alist
+     (assoc-set! counter-alist alist-key (1+ output-count)))
+    (set! current-outfile-name result)
+    result))
 
-    (if (> count 0)
-	(set! base (format #f "~a-~a" base count)))
-    (ly:parser-define! parser 'output-count (1+ count))
-    (process-procedure book paper layout base)
-    ))
+(define (print-book-with parser book process-procedure)
+  (let* ((paper (ly:parser-lookup parser '$defaultpaper))
+	 (layout (ly:parser-lookup parser '$defaultlayout))
+	 (outfile-name (get-outfile-name parser)))
+    (process-procedure book paper layout outfile-name)))
 
 (define-public (print-book-with-defaults parser book)
   (print-book-with parser book ly:book-process))
@@ -141,11 +215,35 @@
 (define-public (print-book-with-defaults-as-systems parser book)
   (print-book-with parser book ly:book-process-to-systems))
 
+;; Add a score to the current bookpart, book or toplevel
+(define-public (add-score parser score)
+    (cond
+      ((ly:parser-lookup parser '$current-bookpart)
+          ((ly:parser-lookup parser 'bookpart-score-handler)
+	        (ly:parser-lookup parser '$current-bookpart) score))
+      ((ly:parser-lookup parser '$current-book)
+          ((ly:parser-lookup parser 'book-score-handler)
+	        (ly:parser-lookup parser '$current-book) score))
+      (else
+          ((ly:parser-lookup parser 'toplevel-score-handler) parser score))))
+
+(define-public (add-text parser text)
+  (add-score parser (list text)))
+
+(define-public (add-music parser music)
+  (collect-music-aux (lambda (score)
+		       (add-score parser score))
+                     parser
+		     music))
+
+
 ;;;;;;;;;;;;;;;;
 ;; alist
 
 (define-public assoc-get ly:assoc-get)
 
+(define-public chain-assoc-get ly:chain-assoc-get)
+
 (define-public (uniqued-alist alist acc)
   (if (null? alist) acc
       (if (assoc (caar alist) acc)
@@ -156,21 +254,6 @@
   (string<? (symbol->string (car x))
 	    (symbol->string (car y))))
 
-(define-public (chain-assoc-get x alist-list . default)
-  "Return ALIST entry for X. Return DEFAULT (optional, else #f) if not
-found."
-
-  (define (helper x alist-list default)
-    (if (null? alist-list)
-	default
-	(let* ((handle (assoc x (car alist-list))))
-	  (if (pair? handle)
-	      (cdr handle)
-	      (helper x (cdr alist-list) default)))))
-
-  (helper x alist-list
-	  (if (pair? default) (car default) #f)))
-
 (define (map-alist-vals func list)
   "map FUNC over the vals of  LIST, leaving the keys."
   (if (null?  list)
@@ -179,21 +262,22 @@ found."
 	    (map-alist-vals func (cdr list)))))
 
 (define (map-alist-keys func list)
-  "map FUNC over the keys of an alist LIST, leaving the vals. "
+  "map FUNC over the keys of an alist LIST, leaving the vals."
   (if (null?  list)
       '()
       (cons (cons (func (caar list)) (cdar list))
 	    (map-alist-keys func (cdr list)))))
 
 (define-public (first-member members lst)
-  "Return first successful MEMBER of member from MEMBERS in LST."
+  "Return first successful member (of member) from @var{members} in
+@var{lst}."
   (if (null? members)
       #f
       (let ((m (member (car members) lst)))
 	(if m m (first-member (cdr members) lst)))))
 
 (define-public (first-assoc keys lst)
-  "Return first successful ASSOC of key from KEYS in LST."
+  "Return first successful assoc of key from @var{keys} in @var{lst}."
   (if (null? keys)
       #f
       (let ((k (assoc (car keys) lst)))
@@ -206,6 +290,40 @@ found."
 	    (cons (cdar alist)
 		  (flatten-alist (cdr alist))))))
 
+(define (assoc-remove key alist)
+  "Remove key (and its corresponding value) from an alist.
+   Different than assoc-remove! because it is non-destructive."
+  (define (assoc-crawler key l r)
+    (if (null? r)
+        l
+        (if (equal? (caar r) key)
+            (append l (cdr r))
+            (assoc-crawler key (append l `(,(car r))) (cdr r)))))
+  (assoc-crawler key '() alist))
+
+(define-public (map-selected-alist-keys function keys alist)
+  "Return @var{alist} with @var{function} applied to all of the values
+in list @var{keys}.
+
+For example:
+@example
+@code{guile> (map-selected-alist-keys - '(a b) '((a . 1) (b . -2) (c . 3) (d . 4)))}
+@code{((a . -1) (b . 2) (c . 3) (d . 4)}
+@end example"
+   (define (map-selected-alist-keys-helper function key alist)
+     (map
+     (lambda (pair)
+       (if (equal? key (car pair))
+           (cons key (function (cdr pair)))
+           pair))
+     alist))
+   (if (null? keys)
+       alist
+       (map-selected-alist-keys
+         function
+         (cdr keys)
+         (map-selected-alist-keys-helper function (car keys) alist))))
+
 ;;;;;;;;;;;;;;;;
 ;; vector
 
@@ -222,7 +340,7 @@ found."
   (hash-fold (lambda (k v acc) (acons  k v  acc))
 	     '() t))
 
-;; todo: code dup with C++. 
+;; todo: code dup with C++.
 (define-safe-public (alist->hash-table lst)
   "Convert alist to table"
   (let ((m (make-hash-table (length lst))))
@@ -235,7 +353,7 @@ found."
 (define (functional-or . rest)
   (if (pair? rest)
       (or (car rest)
-	   (apply functional-and (cdr rest)))
+	   (apply functional-or (cdr rest)))
       #f))
 
 (define (functional-and . rest)
@@ -246,14 +364,14 @@ found."
 
 (define (split-list lst n)
   "Split LST in N equal sized parts"
-  
+
   (define (helper todo acc-vector k)
     (if (null? todo)
 	acc-vector
 	(begin
 	  (if (< k 0)
 	      (set! k (+ n k)))
-	    
+
 	  (vector-set! acc-vector k (cons (car todo) (vector-ref acc-vector k)))
 	  (helper (cdr todo) acc-vector (1- k)))))
 
@@ -270,7 +388,8 @@ found."
   (helper lst 0))
 
 (define-public (count-list lst)
-  "Given lst (E1 E2 .. ) return ((E1 . 1) (E2 . 2) ... )  "
+  "Given @var{lst} as @code{(E1 E2 .. )}, return
+@code{((E1 . 1) (E2 . 2) ... )}."
 
   (define (helper l acc count)
     (if (pair? l)
@@ -279,9 +398,9 @@ found."
 
 
   (reverse (helper lst '() 1)))
-  
+
 (define-public (list-join lst intermediate)
-  "put INTERMEDIATE  between all elts of LST."
+  "Put @var{intermediate} between all elts of @var{lst}."
 
   (fold-right
    (lambda (elem prev)
@@ -295,23 +414,22 @@ found."
    (lambda (x) x)
    (map proc lst)))
 
-
-(define (flatten-list lst)
-  "Unnest LST" 
-  (if (null? lst)
-      '()
-      (if (pair? (car lst))
-	  (append (flatten-list (car lst)) (flatten-list  (cdr lst)))
-	  (cons (car lst) (flatten-list (cdr lst))))))
+(define-public (flatten-list x)
+  "Unnest list."
+  (cond ((null? x) '())
+        ((not (pair? x)) (list x))
+        (else (append (flatten-list (car x))
+                      (flatten-list (cdr x))))))
 
 (define (list-minus a b)
   "Return list of elements in A that are not in B."
   (lset-difference eq? a b))
 
 (define-public (uniq-list lst)
-  "Uniq LST, assuming that it is sorted. Uses equal? for comparisons."
+  "Uniq @var{lst}, assuming that it is sorted.  Uses @code{equal?}
+for comparisons."
 
-  (reverse! 
+  (reverse!
    (fold (lambda (x acc)
 	   (if (null? acc)
 	       (list x)
@@ -320,57 +438,36 @@ found."
 		   (cons x acc))))
 	 '() lst) '()))
 
-(define (split-at-predicate predicate lst)
- "Split LST = (a_1 a_2 ... a_k b_1 ... b_k)
-  into L1 = (a_1 ... a_k ) and L2 =(b_1 .. b_k) 
-  Such that (PREDICATE a_i a_{i+1}) and not (PREDICATE a_k b_1).
-  L1 is copied, L2 not.
-
-  (split-at-predicate (lambda (x y) (= (- y x) 2)) '(1 3 5 9 11) (cons '() '()))"
- 
- ;; " Emacs is broken
-
- (define (inner-split predicate lst acc)
-   (cond
-    ((null? lst) acc)
-    ((null? (cdr lst))
-     (set-car! acc (cons (car lst) (car acc)))
-     acc)
-    ((predicate (car lst) (cadr lst))
-     (set-car! acc (cons (car lst) (car acc)))
-     (inner-split predicate (cdr lst) acc))
-    (else
-     (set-car! acc (cons (car lst) (car acc)))
-     (set-cdr! acc (cdr lst))
-     acc)))
- 
- (let* ((c (cons '() '())))
-   (inner-split predicate lst  c)
-   (set-car! c (reverse! (car c)))
-   c))
-
-(define-public (split-list-by-separator lst sep?)
-   "(display (split-list-by-separator '(a b c / d e f / g) (lambda (x) (equal? x '/))))
-   =>
-   ((a b c) (d e f) (g))
-  "
-   ;; " Emacs is broken
-   (define (split-one sep?  lst acc)
-     "Split off the first parts before separator and return both parts."
-     (if (null? lst)
-	 (cons acc '())
-	 (if (sep? (car lst))
-	     (cons acc (cdr lst))
-	     (split-one sep? (cdr lst) (cons (car lst) acc)))))
-   
-   (if (null? lst)
-       '()
-       (let* ((c (split-one sep? lst '())))
-	 (cons (reverse! (car c) '()) (split-list-by-separator (cdr c) sep?)))))
+(define (split-at-predicate pred lst)
+  "Split LST into two lists at the first element that returns #f for
+  (PRED previous_element element).  Return the two parts as a pair.
+  Example: (split-at-predicate < '(1 2 3 2 1)) ==> ((1 2 3) . (2 1))"
+  (if (null? lst)
+      (list lst)
+      (let ((i (list-index (lambda (x y) (not (pred x y)))
+			   lst
+			   (cdr lst))))
+        (if i
+            (cons (take lst (1+ i)) (drop lst (1+ i)))
+            (list lst)))))
+
+(define-public (split-list-by-separator lst pred)
+  "Split @var{lst} at each element that satisfies @var{pred}, and return
+the parts (with the separators removed) as a list of lists.  For example,
+executing @samp{(split-list-by-separator '(a 0 b c 1 d) number?)} returns
+@samp{((a) (b c) (d))}."
+  (let loop ((result '()) (lst lst))
+    (if (and lst (not (null? lst)))
+        (loop
+          (append result
+                  (list (take-while (lambda (x) (not (pred x))) lst)))
+          (let ((tail (find-tail pred lst)))
+            (if tail (cdr tail) #f)))
+       result)))
 
 (define-public (offset-add a b)
   (cons (+ (car a) (car b))
-	(+ (cdr a) (cdr b)))) 
+	(+ (cdr a) (cdr b))))
 
 (define-public (offset-flip-y o)
   (cons (car o) (- (cdr o))))
@@ -386,66 +483,61 @@ found."
 	    (ly:list->offsets accum (cddr coords)))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; numbers
-
-(if (not (defined? 'nan?)) ;; guile 1.6 compat
-    (define-public (nan? x) (not (or (< 0.0 x)
-				     (> 0.0 x)
-				     (= 0.0 x)))))
+;; intervals
 
-(if (not (defined? 'inf?))
-    (define-public (inf? x) (= (/ 1.0 x) 0.0)))
+(define-public empty-interval '(+inf.0 . -inf.0))
 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; intervals
+(define-public (symmetric-interval expr)
+  (cons (- expr) expr))
 
 (define-public (interval-length x)
-  "Length of the number-pair X, when an interval"
+  "Length of the number-pair @var{x}, if an interval."
   (max 0 (- (cdr x) (car x))))
 
-(define-public interval-start car)
 (define-public (ordered-cons a b)
   (cons (min a b)
 	(max a b)))
 
-(define-public interval-end cdr)
-
 (define-public (interval-bound interval dir)
   ((if (= dir RIGHT) cdr car) interval))
 
 (define-public (interval-index interval dir)
-  "Interpolate INTERVAL between between left (DIR=-1) and right (DIR=+1)"
-  
+  "Interpolate @var{interval} between between left (@var{dir}=-1) and
+right (@var{dir}=+1)."
+
   (* (+  (interval-start interval) (interval-end interval)
 	 (* dir (- (interval-end interval) (interval-start interval))))
      0.5))
 
 (define-public (interval-center x)
-  "Center the number-pair X, when an interval"
+  "Center the number-pair @var{x}, if an interval."
   (if (interval-empty? x)
       0.0
       (/ (+ (car x) (cdr x)) 2)))
 
 (define-public interval-start car)
+
 (define-public interval-end cdr)
-(define-public (interval-translate iv amount)
-  (cons (+ amount (car iv))
-	(+ amount (cdr iv))))
 
 (define (other-axis a)
   (remainder (+ a 1) 2))
 
 (define-public (interval-widen iv amount)
-   (cons (- (car iv) amount)
-         (+ (cdr iv) amount)))
-
+  (cons (- (car iv) amount)
+    (+ (cdr iv) amount)))
 
 (define-public (interval-empty? iv)
    (> (car iv) (cdr iv)))
 
 (define-public (interval-union i1 i2)
-   (cons (min (car i1) (car i2))
-	 (max (cdr i1) (cdr i2))))
+  (cons
+    (min (car i1) (car i2))
+    (max (cdr i1) (cdr i2))))
+
+(define-public (interval-intersection i1 i2)
+   (cons
+     (max (car i1) (car i2))
+     (min (cdr i1) (cdr i2))))
 
 (define-public (interval-sane? i)
   (not (or  (nan? (car i))
@@ -454,6 +546,108 @@ found."
 	    (inf? (cdr i))
 	    (> (car i) (cdr i)))))
 
+(define-public (add-point interval p)
+  (cons (min (interval-start interval) p)
+        (max (interval-end interval) p)))
+
+(define-public (reverse-interval iv)
+  (cons (cdr iv) (car iv)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; coordinates
+
+(define coord-x car)
+(define coord-y cdr)
+
+(define (coord-operation operator operand coordinate)
+  (if (pair? operand)
+    (cons (operator (coord-x operand) (coord-x coordinate))
+          (operator (coord-y operand) (coord-y coordinate)))
+    (cons (operator operand (coord-x coordinate))
+          (operator operand (coord-y coordinate)))))
+
+(define (coord-apply function coordinate)
+  (if (pair? function)
+    (cons
+      ((coord-x function) (coord-x coordinate))
+      ((coord-y function) (coord-y coordinate)))
+    (cons
+      (function (coord-x coordinate))
+      (function (coord-y coordinate)))))
+
+(define-public (coord-translate coordinate amount)
+  (coord-operation + amount coordinate))
+
+(define-public (coord-scale coordinate amount)
+  (coord-operation * amount coordinate))
+
+(define-public (coord-rotate coordinate degrees-in-radians)
+  (let*
+    ((coordinate
+      (cons
+        (exact->inexact (coord-x coordinate))
+        (exact->inexact (coord-y coordinate))))
+     (radius
+      (sqrt
+        (+ (* (coord-x coordinate) (coord-x coordinate))
+           (* (coord-y coordinate) (coord-y coordinate)))))
+    (angle (angle-0-2pi (atan (coord-y coordinate) (coord-x coordinate)))))
+   (cons
+     (* radius (cos (+ angle degrees-in-radians)))
+     (* radius (sin (+ angle degrees-in-radians))))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; trig
+
+(define-public PI (* 4 (atan 1)))
+
+(define-public TWO-PI (* 2 PI))
+
+(define-public PI-OVER-TWO (/ PI 2))
+
+(define-public THREE-PI-OVER-TWO (* 3 PI-OVER-TWO))
+
+(define-public (cyclic-base-value value cycle)
+  "Take @var{value} and modulo-maps it between 0 and base @var{cycle}."
+  (if (< value 0)
+      (cyclic-base-value (+ value cycle) cycle)
+      (if (>= value cycle)
+          (cyclic-base-value (- value cycle) cycle)
+          value)))
+
+(define-public (angle-0-2pi angle)
+  "Take @var{angle} (in radians) and maps it between 0 and 2pi."
+  (cyclic-base-value angle TWO-PI))
+
+(define-public (angle-0-360 angle)
+  "Take @var{angle} (in degrees) and maps it between 0 and 360 degrees."
+  (cyclic-base-value angle 360.0))
+
+(define-public PI-OVER-180  (/ PI 180))
+
+(define-public (degrees->radians angle-degrees)
+  "Convert the given angle from degrees to radians."
+  (* angle-degrees PI-OVER-180))
+
+(define-public (ellipse-radius x-radius y-radius angle)
+  (/
+    (* x-radius y-radius)
+    (sqrt
+      (+ (* (expt y-radius 2)
+            (* (cos angle) (cos angle)))
+        (* (expt x-radius 2)
+           (* (sin angle) (sin angle)))))))
+
+(define-public (polar->rectangular radius angle-in-degrees)
+  "Return polar coordinates (@var{radius}, @var{angle-in-degrees})
+as rectangular coordinates @ode{(x-length . y-length)}."
+
+  (let ((complex (make-polar
+                    radius
+                    (degrees->radians angle-in-degrees))))
+     (cons
+       (real-part complex)
+       (imag-part complex))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; string
@@ -462,10 +656,10 @@ found."
   (equal? suffix (substring s
 			    (max 0 (- (string-length s) (string-length suffix)))
 			    (string-length s))))
-	     
+
 (define-public (string-startswith s prefix)
   (equal? prefix (substring s 0 (min (string-length s) (string-length prefix)))))
-	     
+
 (define-public (string-encode-integer i)
   (cond
    ((= i  0) "o")
@@ -492,14 +686,15 @@ found."
 		 (ly:number->string (cdr c))))
 
 (define-public (dir-basename file . rest)
-  "Strip suffixes in REST, but leave directory component for FILE."
+  "Strip suffixes in @var{rest}, but leave directory component for
+@var{file}."
   (define (inverse-basename x y) (basename y x))
   (simple-format #f "~a/~a" (dirname file)
 		 (fold inverse-basename file rest)))
 
 (define-public (write-me message x)
-  "Return X.  Display MESSAGE and write X.  Handy for debugging,
-possibly turned off."
+  "Return @var{x}.  Display @var{message} and write @var{x}.
+Handy for debugging, possibly turned off."
   (display message) (write x) (newline) x)
 ;;  x)
 
@@ -521,7 +716,7 @@ possibly turned off."
   (cons (f (car x)) (f (cdr x))))
 
 (define-public (list-insert-separator lst between)
-  "Create new list, inserting BETWEEN between elements of LIST"
+  "Create new list, inserting @var{between} between elements of @var{lst}."
   (define (conc x y )
     (if (eq? y #f)
 	(list x)
@@ -529,7 +724,7 @@ possibly turned off."
   (fold-right conc #f lst))
 
 (define-public (string-regexp-substitute a b str)
-  (regexp-substitute/global #f a str 'pre b 'post)) 
+  (regexp-substitute/global #f a str 'pre b 'post))
 
 (define (regexp-split str regex)
   (define matches '())
@@ -552,31 +747,80 @@ possibly turned off."
    (reverse matches))
 
 ;;;;;;;;;;;;;;;;
-; other
+;; other
+
 (define (sign x)
   (if (= x 0)
       0
       (if (< x 0) -1 1)))
 
+(define-public (binary-search start end getter target-val)
+  (_i "Find the index between @var{start} and @var{end} (an integer)
+which produces the closest match to @var{target-val} if
+applied to function @var{getter}.")
+  (if (<= end start)
+      start
+      (let* ((compare (quotient (+ start end) 2))
+	     (get-val (getter compare)))
+	(cond
+	 ((< target-val get-val)
+	  (set! end (1- compare)))
+	 ((< get-val target-val)
+	  (set! start (1+ compare))))
+	(binary-search start end getter target-val))))
 
 (define-public (car< a b)
   (< (car a) (car b)))
 
+(define-public (car<= a b)
+  (<= (car a) (car b)))
+
 (define-public (symbol<? lst r)
   (string<? (symbol->string lst) (symbol->string r)))
 
 (define-public (symbol-key<? lst r)
   (string<? (symbol->string (car lst)) (symbol->string (car r))))
 
+(define-public (eval-carefully symbol module . default)
+  "Check whether all symbols in expr @var{symbol} are reachable
+in module @var{module}.  In that case evaluate, otherwise
+print a warning and set an optional @var{default}."
+  (let* ((unavailable? (lambda (sym)
+                         (not (module-defined? module sym))))
+	 (sym-unavailable (if (pair? symbol)
+	                      (filter
+			        unavailable?
+			        (filter symbol? (flatten-list symbol)))
+			      (if (unavailable? symbol)
+			           #t
+				   '()))))
+    (if (null? sym-unavailable)
+        (eval symbol module)
+        (let* ((def (and (pair? default) (car default))))
+          (ly:programming-error
+            "cannot evaluate ~S in module ~S, setting to ~S"
+            (object->string symbol)
+            (object->string module)
+            (object->string def))
+          def))))
+
+;;
+;; don't confuse users with #<procedure .. > syntax.
 ;;
-;; don't confuse users with #<procedure .. > syntax. 
-;; 
 (define-public (scm->string val)
-  (if (and (procedure? val) (symbol? (procedure-name val)))
+  (if (and (procedure? val)
+	   (symbol? (procedure-name val)))
       (symbol->string (procedure-name val))
       (string-append
-       (if (self-evaluating? val) "" "'")
-       (call-with-output-string (lambda (port) (display val port))))))
+       (if (self-evaluating? val)
+	   (if (string? val)
+	       "\""
+	       "")
+	   "'")
+       (call-with-output-string (lambda (port) (display val port)))
+       (if (string? val)
+	   "\""
+	   ""))))
 
 (define-public (!= lst r)
   (not (= lst r)))
@@ -592,17 +836,11 @@ possibly turned off."
 
 ;;; FONT may be font smob, or pango font string...
 (define-public (font-name-style font)
-      ;; FIXME: ughr, (ly:font-name) sometimes also has Style appended.
+  (if (string? font)
+      (string-downcase font)
       (let* ((font-name (ly:font-name font))
-	     (full-name (if font-name font-name (ly:font-file-name font)))
-	     (name-style (string-split full-name #\-)))
-	;; FIXME: ughr, barf: feta-alphabet is actually emmentaler
-	(if (string-prefix? "feta-alphabet" full-name)
-	    (list "emmentaler"
-		  (substring  full-name (string-length "feta-alphabet")))
-	    (if (not (null? (cdr name-style)))
-	    name-style
-	    (append name-style '("Regular"))))))
+	     (full-name (if font-name font-name (ly:font-file-name font))))
+	  (string-downcase full-name))))
 
 (define-public (modified-font-metric-font-scaling font)
   (let* ((designsize (ly:font-design-size font))
@@ -614,17 +852,12 @@ possibly turned off."
     scaling))
 
 (define-public (version-not-seen-message input-file-name)
-  (ly:message
-   "~a:0: ~a: ~a" 
-    input-file-name
-    (_ "warning: ")
-    (format #f
-	    (_ "no \\version statement found, please add~afor future compatibility")
-	    (format #f "\n\n\\version ~s\n\n" (lilypond-version)))))
+  (ly:warning-located
+    (ly:format "~a:0" input-file-name)
+    (_ "no \\version statement found, please add~afor future compatibility")
+    (format #f "\n\n\\version ~s\n\n" (lilypond-version))))
 
 (define-public (old-relative-not-used-message input-file-name)
-  (ly:message
-   "~a:0: ~a: ~a" 
-    input-file-name
-    (_ "warning: ")
+  (ly:warning-located
+    (ly:format "~a:0" input-file-name)
     (_ "old relative compatibility not used")))