[xsl] How can I achieve correct tail-recursion ?

Hello, I'm using SaxonHE 9.2 with a layout sheet for braille output. I
need to process every child of node "doc" while remembering line and
page numbers for each child I process. Here's the sub-part of the
sheet ("doc" is the root of my document) :
----------------
[...]
<xsl:template match="doc">
        <xsl:apply-templates select="@*" />
        <xsl:call-template name="miseEnPage"/>
</xsl:template>

<!-- TEMPLATE PRINCIPAL DE MISE EN PAGE -->
<xsl:template name="miseEnPage">
        <xsl:param name="numNoeud" as="xs:integer" select="1" />
        <xsl:param name="numPage" as="xs:integer" select="1" />
        <xsl:param name="numLigne" as="xs:integer" select="1" />
        
        <xsl:variable name="texteMisEnPage" as="xs:string*">
                <xsl:choose>
                        <!-- saut de page -->
                        <xsl:when test="*[$numNoeud][self::page-break]">
                                <xsl:value-of
select="translate(doc:sautePage(true(),$numLigne,$numPage),concat($sautAGenerer,$espace),'&#10;&pt;')"/>
                        </xsl:when>
                        <xsl:when test="not(string(*[$numNoeud]))"><!-- le fils 
est vide -->
                                <xsl:call-template name="gestionLignesVides">
                                        <xsl:with-param name="numNoeud" 
select="$numNoeud" />
                                        <xsl:with-param name="numLigne" 
select="$numLigne" />
                                        <xsl:with-param name="numPage" 
select="$numPage" />
                                </xsl:call-template>
                        </xsl:when>
                        <xsl:when test="*[$numNoeud][self::ul or self::ol]"> 
<!-- liste à puces -->
                                <xsl:call-template name="MEPliste">
                                        <xsl:with-param name="noeud" 
select="*[$numNoeud]" />
                                        <xsl:with-param name="numPage" 
select="$numPage" tunnel="yes"/>
                                        <xsl:with-param name="numLigne" 
select="$numLigne" tunnel="yes" />
                                </xsl:call-template>
                        </xsl:when>
[... other xsl:when ...]
                        <xsl:otherwise><xsl:text></xsl:text></xsl:otherwise>
                </xsl:choose>
        </xsl:variable>
        
        <!-- ******** affichage du texte ********* -->
        <xsl:variable name="texteMisEnPageJoint"
select="string-join($texteMisEnPage,'')" as="xs:string" />
        <xsl:value-of select="$texteMisEnPageJoint" />
        
        <xsl:variable name="nouvPage" as="xs:integer"
select="doc:nouvellePage($texteMisEnPageJoint,$numPage)" />
        <xsl:variable name="nouvLigne" as="xs:integer"
select="doc:nouvelleLigne($texteMisEnPageJoint,$numLigne)" />

<!-- here comes the tail recursion -->
        <xsl:if test="$numNoeud &lt; count(*)">
                <xsl:call-template name="miseEnPage">
                        <xsl:with-param name="numNoeud" select="$numNoeud+1" />
                        <xsl:with-param name="numPage" select="$nouvPage" />
                        <xsl:with-param name="numLigne" select="$nouvLigne" />
                </xsl:call-template>
        </xsl:if>
        <xsl:if test="$mise_en_page and ($numNoeud = count(*))"> <!-- appel
final pour num de page et saut de page -->
                <xsl:variable name="completeLastPage" as="xs:string"
select="doc:sautePage(true(),$nouvLigne,$nouvPage)" />
                <xsl:value-of
select="translate($completeLastPage,concat($sautAGenerer,$espace),'&#10;&pt;')"
/>
        </xsl:if>
</xsl:template>

----------------------------------
I've read Saxon optimizes tail recursion as an iterating function,
this would mean no stack overflow.
I switched back to Saxon 9.1 and tried to achieve this with
saxon:iterate and parameters :
---------------------------------
<xsl:template name="miseEnPage">

        <saxon:iterate select="*" xmlns:saxon="http://saxon.sf.net/";
xsl:extension-element-prefixes="saxon">
                <xsl:param name="numPage" as="xs:integer" select="1" />
                <xsl:param name="numLigne" as="xs:integer" select="1" />
                
                <xsl:variable name="texteMisEnPage" as="xs:string*">
                        <xsl:choose>
                                <!-- saut de page -->
                                <xsl:when test="self::page-break">
                                        <!--<xsl:message select="OUI"/>-->
                                        <xsl:value-of
select="translate(doc:sautePage(true(),$numLigne,$numPage),concat($sautAGenerer,$espace),'&#10;&pt;')"/>
                                </xsl:when>
                                <xsl:when test="not(string(.))"><!-- le fils 
est vide -->
                                        <xsl:call-template 
name="gestionLignesVides">
                                                <xsl:with-param name="numLigne" 
select="$numLigne" />
                                                <xsl:with-param name="numPage" 
select="$numPage" />
                                        </xsl:call-template>
                                </xsl:when>
                                <xsl:when test="self::ul or self::ol"> <!-- 
liste à puces -->
                                        <xsl:call-template name="MEPliste">
                                                <xsl:with-param name="numPage" 
select="$numPage" tunnel="yes"/>
                                                <xsl:with-param name="numLigne" 
select="$numLigne" tunnel="yes" />
                                        </xsl:call-template>
                                </xsl:when>
[... other xsl:when ...]
                                
<xsl:otherwise><xsl:text></xsl:text></xsl:otherwise>
                        </xsl:choose>
                </xsl:variable>
                
                <!-- ******** affichage du texte ********* -->
                <xsl:variable name="texteMisEnPageJoint"
select="string-join($texteMisEnPage,'')" as="xs:string" />
                <xsl:value-of select="$texteMisEnPageJoint" />
                
                <saxon:continue>
                        <xsl:with-param name="numPage" as="xs:integer"
select="doc:nouvellePage($texteMisEnPageJoint,$numPage)" />
                        <xsl:with-param name="numLigne" as="xs:integer"
select="doc:nouvelleLigne($texteMisEnPageJoint,$numLigne)" />
                </saxon:continue>
        </saxon:iterate>
        <!-- <xsl:value-of
select="concat('nouvpage',$nouvPage,'nouvligne',$nouvLigne,'matches ',
string($pagesEnPlus),' ',string($lignesEnPlus))" /> -->
</xsl:template>

-----------------------------------

With saxon:iterate , no more stack overflow and processing is about
10x faster ! I suppose I would get a nearby result if my first sheet
did correct tail recursion. How can I modify it to do correct tail
recursion ? I couldn't find any doc about it on the W3C website, nor
on saxonica.com, nor on http://saxon.markmail.org/.

Thanks for any help,
Regards
Frédéric Schwebel
http://sourceforge.net/projects/nat-braille/

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