From 360100402cac5c946b90afa026882304031308b9 Mon Sep 17 00:00:00 2001
From: Thomas Weber <thomas.weber@notengrafik.com>
Date: Fri, 13 Jan 2017 12:37:37 +0100
Subject: [PATCH] Generalize clef handling

---
 mei2ly.xsl      | 82 ++++++++++++++++++++++++------------------
 tests/clefs.mei | 94 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 142 insertions(+), 34 deletions(-)
 create mode 100644 tests/clefs.mei

diff --git a/mei2ly.xsl b/mei2ly.xsl
index 3c41feb..6eb05b4 100644
--- a/mei2ly.xsl
+++ b/mei2ly.xsl
@@ -27,6 +27,27 @@
   <xsl:key name="isBeamEnd" match="mei:beam" use=".//*[self::mei:note or self::mei:rest or self::mei:chord or self::mei:space][last()]/generate-id()"/>
   <xsl:key name="isBeamEnd" match="@beam[contains(., 't')]" use="generate-id(..)"/>
   <xsl:key name="isBeamEnd" match="mei:beamSpan[not(@beam.with)]" use="key('idref', @endid)/generate-id()"/>
+  <xsl:variable name="namesOfElementsWithDuration" select="('bTrem', 'chord', 'fTrem', 'halfmRpt', 'mRest', 'mSpace', 'note', 'rest', 'space', 'beam', 'beatRpt', 'mRpt', 'mRpt2', 'multiRest', 'multiRpt', 'tuplet')"/>
+  <xsl:key name="staffDefByFirstAffectedElement" match="mei:staffDef">
+    <xsl:variable name="hasPrecedingLayerContent" as="xs:boolean" 
+      select="ancestor::mei:layer and preceding-sibling::mei:*[local-name()=$namesOfElementsWithDuration]"/>
+    <xsl:variable name="firstAffectedLayerContentElement" 
+      select=".[$hasPrecedingLayerContent]/following-sibling::mei:*[name()=$namesOfElementsWithDuration][1]"/>
+    <xsl:choose>
+      <xsl:when test="$firstAffectedLayerContentElement">
+        <!-- This staffDef takes effect in the middle of a layer -->
+        <xsl:value-of select="$firstAffectedLayerContentElement/generate-id()"/>
+      </xsl:when>
+      <xsl:when test="ancestor::mei:staff and not($hasPrecedingLayerContent)">
+        <!-- This <staffDef> affects the <staff> element it lives in. -->
+        <xsl:value-of select="ancestor::mei:staff[1]/generate-id()"/>
+      </xsl:when>
+      <xsl:otherwise>
+        <!-- This <staffDef> takes effect in the next <staff> -->
+        <xsl:value-of select="following::mei:staff[@n=current()/@n][1]/generate-id()"/>
+      </xsl:otherwise>
+    </xsl:choose>
+  </xsl:key>
   <xsl:template match="/">
     <xsl:text>\version "2.18.2"&#10;</xsl:text>
     <xsl:text>#(ly:set-option 'point-and-click #f)&#10;</xsl:text>
@@ -169,16 +190,7 @@
           <xsl:call-template name="setBarNumber" />
         </xsl:if>
         <!-- add clef change -->
-        <xsl:if test="generate-id(preceding::mei:staffDef[@n = $staffNumber][@clef.shape][1]/following::mei:measure[1]) = $currentMeasure">
-          <xsl:call-template name="setClef">
-            <xsl:with-param name="clefColor" select="preceding::mei:staffDef[@n = $staffNumber][@clef.shape][1]/@clef.color" />
-            <xsl:with-param name="clefDis" select="preceding::mei:staffDef[@n = $staffNumber][@clef.shape][1]/@clef.dis" />
-            <xsl:with-param name="clefDisPlace" select="preceding::mei:staffDef[@n = $staffNumber][@clef.shape][1]/@clef.dis.place" />
-            <xsl:with-param name="clefLine" select="preceding::mei:staffDef[@n = $staffNumber][@clef.shape][1]/@clef.line" />
-            <xsl:with-param name="clefShape" select="preceding::mei:staffDef[@n = $staffNumber][@clef.shape][1]/@clef.shape" />
-          </xsl:call-template>
-          <xsl:text>&#10;&#32;&#32;</xsl:text>
-        </xsl:if>
+        <xsl:apply-templates select="(key('staffDefByFirstAffectedElement', generate-id())/(@clef.shape, mei:clef))[last()]"/>
         <!-- add key signature change -->
         <xsl:if test="generate-id(ancestor::mei:measure/preceding-sibling::*[contains(local-name(),'Def')][@*[starts-with(name(),'key')]][1]/following-sibling::mei:measure[1]) = $currentMeasure">
           <xsl:call-template name="setKey">
@@ -280,10 +292,10 @@
   </xsl:template>
   <!-- MEI score element -->
   <xsl:template match="mei:score">
-    <xsl:apply-templates select="descendant::mei:scoreDef[1]" />
+    <xsl:apply-templates select="descendant::mei:scoreDef[1]" mode="score-setup"/>
   </xsl:template>
   <!-- MEI score definition -->
-  <xsl:template match="mei:scoreDef">
+  <xsl:template match="mei:scoreDef" mode="score-setup">
     <!-- lilypond score block -->
     <xsl:text>\score { &lt;&lt;&#10;</xsl:text>
     <xsl:if test="ancestor::mei:mdiv[1]//@source">
@@ -294,7 +306,7 @@
       </xsl:for-each>
       <xsl:text>)&#10;</xsl:text>
     </xsl:if>
-    <xsl:apply-templates select="mei:staffGrp|mei:staffDef" />
+    <xsl:apply-templates select="mei:staffGrp|mei:staffDef" mode="score-setup"/>
     <xsl:text>&gt;&gt;&#10;</xsl:text>
     <!-- lilypond layout block -->
     <xsl:text>\layout {&#10;</xsl:text>
@@ -366,7 +378,7 @@
     </xsl:if>
   </xsl:template>
   <!-- MEI staff group -->
-  <xsl:template match="mei:staffGrp">
+  <xsl:template match="mei:staffGrp" mode="score-setup">
     <xsl:text>\new StaffGroup </xsl:text>
     <xsl:if test="@label or @label.abbr or child::mei:label">
       <xsl:text>\with { </xsl:text>
@@ -375,11 +387,11 @@
     </xsl:if>
     <xsl:text>&lt;&lt;&#10;</xsl:text>
     <xsl:call-template name="setStaffGrpStyle" />
-    <xsl:apply-templates select="mei:staffGrp|mei:staffDef" />
+    <xsl:apply-templates select="mei:staffGrp|mei:staffDef" mode="score-setup"/>
     <xsl:text>&gt;&gt;&#10;</xsl:text>
   </xsl:template>
   <!-- MEI staff definitons -->
-  <xsl:template match="mei:staffDef">
+  <xsl:template match="mei:staffDef" mode="score-setup">
     <xsl:variable name="mdivNumber" select="ancestor::mei:mdiv/@n" />
     <xsl:variable name="staffNumber" select="@n" />
     <xsl:text> \new </xsl:text>
@@ -457,16 +469,6 @@
     </xsl:choose>
     <!-- set MEILER default styles -->
     <xsl:text>\set tieWaitForNote = ##t&#10; </xsl:text>
-    <xsl:if test="ancestor-or-self::*/@*[starts-with(name(),'clef.')]">
-      <xsl:call-template name="setClef">
-        <xsl:with-param name="clefColor" select="@clef.color" />
-        <xsl:with-param name="clefDis" select="@clef.dis" />
-        <xsl:with-param name="clefDisPlace" select="@clef.dis.place" />
-        <xsl:with-param name="clefLine" select="@clef.line" />
-        <xsl:with-param name="clefShape" select="@clef.shape" />
-      </xsl:call-template>
-    </xsl:if>
-    <xsl:apply-templates select="mei:clef" />
     <xsl:call-template name="setKey">
       <xsl:with-param name="keyTonic" select="ancestor-or-self::*/@key.pname" />
       <xsl:with-param name="keyAccid" select="ancestor-or-self::*/@key.accid" />
@@ -559,7 +561,7 @@
     <xsl:text>}&#32;</xsl:text>
   </xsl:template>
   <!-- MEI measure -->
-  <xsl:template name="measure" match="mei:measure">
+  <xsl:template match="mei:measure">
     <xsl:value-of select="'  '" />
     <xsl:if test="(ancestor::mei:measure[@n and not(@metcon='false')]/@n != preceding::mei:measure[@n and not(@metcon='false')][1]/@n + 1)">
       <xsl:call-template name="setBarNumber" />
@@ -595,13 +597,25 @@
       <xml:text>\\ </xml:text>
     </xsl:if>
   </xsl:template>
+  <!-- MEI staffDef (inside musical flow) -->
+  <xsl:template match="mei:staffDef[ancestor::mei:layer]">
+    <xsl:apply-templates select="(mei:clef, @clef.shape)[1]"/>
+  </xsl:template>
   <!-- MEI clefs -->
-  <xsl:template name="setClef" match="mei:clef">
-    <xsl:param name="clefColor" select="@color" />
-    <xsl:param name="clefDis" select="@dis" />
-    <xsl:param name="clefDisPlace" select="@dis.place" />
-    <xsl:param name="clefLine" select="@line" />
-    <xsl:param name="clefShape" select="@shape" />
+  <xsl:template match="mei:clef|@clef.shape">
+    <xsl:param name="clefColor" select="@color|../@clef.color" />
+    <xsl:param name="clefDis" select="@dis|../@clef.dis" />
+    <xsl:param name="clefDisPlace" select="@dis.place|../@clef.dis.place" />
+    <xsl:param name="clefLine" select="@line|../@clef.line" />
+    <xsl:param name="clefShape" select="@shape|../@clef.shape" />
+    <xsl:variable name="mei2lyClefMap">
+      <clef mei="G" ly="G"/>
+      <clef mei="F" ly="F"/>
+      <clef mei="C" ly="C"/>
+      <clef mei="perc" ly="percussion"/>
+      <clef mei="TAB" ly="tab"/>
+      <clef mei="GG" ly="GG"/><!-- Not working in v2.18 and earlier? -->
+    </xsl:variable>
     <xsl:variable name="clefTrans">
       <xsl:choose>
         <xsl:when test="$clefDisPlace='above'">
@@ -641,7 +655,7 @@
     <xsl:if test="@cautionary">
       <xsl:value-of select="concat('\set Staff.forceClef = ##',substring(@cautionary,1,1),' ')"/>
     </xsl:if>
-    <xsl:value-of select="concat('\set Staff.clefGlyph = #','&quot;clefs.',$clefShape,'&quot; ')" />
+    <xsl:value-of select="concat('\set Staff.clefGlyph = #','&quot;clefs.', $mei2lyClefMap/*[@mei=$clefShape]/@ly,'&quot; ')" />
     <xsl:value-of select="concat('\set Staff.clefPosition = #',$clefPos,' ')" />
     <xsl:value-of select="concat('\set Staff.clefTransposition = #',$clefTrans,' ')" />
     <xsl:value-of select="concat('\set Staff.middleCPosition = #',$clefPos + $cOffset - $clefTrans,' ')" />
diff --git a/tests/clefs.mei b/tests/clefs.mei
new file mode 100644
index 0000000..5da9c54
--- /dev/null
+++ b/tests/clefs.mei
@@ -0,0 +1,94 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<?xml-model href="http://www.music-encoding.org/schema/3.0.0/mei-all.rng" type="application/xml" schematypens="http://relaxng.org/ns/structure/1.0"?>
+<?xml-model href="http://www.music-encoding.org/schema/3.0.0/mei-all.rng" type="application/xml" schematypens="http://purl.oclc.org/dsdl/schematron"?>
+<mei xmlns="http://www.music-encoding.org/ns/mei" meiversion="3.0.0" xmlns:meiler="NS:MEILER_TEST">
+  <meiHead>
+    <fileDesc>
+      <titleStmt>
+        <title>clef change tests</title>
+      </titleStmt>
+      <pubStmt/>
+    </fileDesc>
+    <extMeta>
+      <meiler:test system="bash" input="ly">
+        # Test strategy: We assigned ascending color values to elements in the order of appearance.
+        # We expect the order to be the same in the output.
+        testcolors=$(egrep -o 'rgb-color[^)]+' "$ly" | egrep --color=never -o '[0-9.].+')
+        # Clefs are flagged with a trailing 255 blue value (1 in lilypond)
+        cleftestcolors=$(echo "$testcolors" | grep --color=never '1$')
+        if echo "$cleftestcolors" | sort | uniq --count | egrep -v '^\s*1' > /dev/null
+        then
+          echo "At least one clef was output twice"
+          exit 1
+        fi
+        if [ $( echo "$cleftestcolors" | wc -l ) -ne 8 ]
+        then 
+          echo "Number of output clefs does not match number of defined clefs"
+          exit 1
+        fi
+        if [ "$testcolors" != "$( echo "$testcolors" | sort )" ]
+        then 
+          echo "At least one clef was output in the wrong place"
+          exit 1 
+        fi
+      </meiler:test>
+    </extMeta>
+  </meiHead>
+  <music>
+    <body>
+      <mdiv>
+        <score>
+          <scoreDef meter.count="4" meter.unit="4">
+            <staffGrp>
+              <staffDef lines="5" n="1">
+                <clef shape="C" line="3" color="rgb(1,0,255)"/>
+              </staffDef>
+              <staffDef clef.line="4" clef.shape="F" lines="5" n="2" clef.color="rgb(100,0,255)"/>
+            </staffGrp>
+          </scoreDef>
+          <section>
+            <measure n="1">
+              <staff n="1">
+                <layer n="1">
+                  <note dur="2" oct="5" pname="c" color="rgb(2,0,0)"/>
+                  <clef shape="F" line="4" color="rgb(3,0,255)"/>
+                  <rest dur="2" color="rgb(4,0,0)"/>
+                </layer>
+              </staff>
+              <staff n="2">
+                <layer n="1">
+                  <note dur="2" oct="3" pname="f" color="rgb(101,0,0)"/>
+                  <staffDef clef.shape="C" clef.line="3" n="2" clef.color="rgb(102,0,255)"/>
+                  <rest dur="2" color="rgb(103,0,0)"/>
+                </layer>
+              </staff>
+            </measure>
+            <measure n="2">
+              <staffDef n="1" clef.shape="G" clef.line="2" clef.color="rgb(5,0,255)"/>
+              <staff n="1">
+                <layer>
+                  <rest dur="2" color="rgb(6,0,0)"/>
+                  <clef shape="perc" line="3" color="rgb(7,0,255)"/>
+                  <rest dur="2" color="rgb(8,0,0)"/>
+                </layer>
+              </staff>
+              <staff n="2">
+                <staffDef n="2" clef.shape="F" clef.line="4" clef.color="rgb(104,0,255)"/>
+                <layer>
+                  <beam>
+                    <note dur="8" pname="c" oct="4" color="rgb(105,0,0)"/>
+                    <note dur="8" pname="c" oct="4" color="rgb(106,0,0)"/>
+                    <clef shape="G" line="2" color="rgb(107,0,255)"/>
+                    <note dur="8" pname="c" oct="4" color="rgb(108,0,0)"/>
+                    <note dur="8" pname="c" oct="4" color="rgb(109,0,0)"/>
+                  </beam>
+                  <rest dur="2" color="rgb(110,0,0)"/>
+                </layer>
+              </staff>
+            </measure>
+          </section>
+        </score>
+      </mdiv>
+    </body>
+  </music>
+</mei>
\ No newline at end of file