A XSL transformation that constructs a single bootstrap.xsl from a bunch of XSL files comprising a pipeline. Useful for getting a XSL pipeline to work in Saxon-JS. In order to do so, first run this XSL, then compile the resulting bootstrap.xsl into SEF format, i.e. by using Oxygen.

create-pipeline.xsl

<xsl:stylesheet
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
    
    <xsl:variable name="steps" select="collection('./xsl?select=*.xsl')" as="node()*"/>
    
    <xsl:template match="/">
        <xsl:for-each select="$steps">
            <xsl:sort select="tokenize(base-uri(.), '/')[last()]"/>
            <xsl:variable name="filename" select="tokenize(base-uri(.), '/')[last()]" as="xs:string"/>
            <xsl:variable name="fullname" select="substring-before($filename, '.xsl')"/>
            <xsl:variable name="shortname" select="concat('step', position())"/>
            <xsl:variable name="package-decl" as="element(xsl:package)">
                <xsl:element name="package" namespace="http://www.w3.org/1999/XSL/Transform">
                    <xsl:attribute name="name" select="$fullname"/>
                    <xsl:attribute name="package-version" select="'1.0'"/>
                    <xsl:attribute name="declared-modes" select="'no'"/>
                    <xsl:attribute name="exclude-result-prefixes" select="'#all'"/>
                    <xsl:attribute name="version" select="'3.0'"/>
                    <xsl:namespace name="{$shortname}" select="concat('urn:pipeline:', $shortname)"/>
                    
                    <xsl:element name="import" namespace="http://www.w3.org/1999/XSL/Transform">
                        <xsl:attribute name="href" select="concat('./xsl/', $filename)"/>
                    </xsl:element>
                    
                    <xsl:element name="function" namespace="http://www.w3.org/1999/XSL/Transform">
                        <xsl:attribute name="name" select="concat($shortname, ':main')"/>
                        <xsl:attribute name="as" select="'document-node()'"/>
                        <xsl:attribute name="visibility" select="'public'"/>
                        <xsl:element name="param" namespace="http://www.w3.org/1999/XSL/Transform">
                            <xsl:attribute name="name" select="'input'"/>
                            <xsl:attribute name="as" select="'document-node()'"/>
                        </xsl:element>
                        <xsl:element name="document" namespace="http://www.w3.org/1999/XSL/Transform">
                            <xsl:element name="apply-templates" namespace="http://www.w3.org/1999/XSL/Transform">
                                <xsl:attribute name="select" select="'$input'"/>
                            </xsl:element>
                        </xsl:element>
                    </xsl:element>
                </xsl:element>
            </xsl:variable>
            <xsl:result-document href="{concat('./package_', $fullname, '.xsl')}" indent="yes">
                <xsl:sequence select="$package-decl"/>
            </xsl:result-document>
        </xsl:for-each>
        
        <xsl:result-document href="./saxon-config.xml" indent="yes">
            <configuration xmlns="http://saxon.sf.net/ns/configuration" edition="EE" label="Import packages">
                <xsltPackages>
                    <xsl:for-each select="$steps">
                        <xsl:variable name="filename" select="tokenize(base-uri(.), '/')[last()]" as="xs:string"/>
                        <xsl:variable name="fullname" select="substring-before($filename, '.xsl')"/>
                        <package name="{$fullname}" version="1.0" sourceLocation="{concat('./package_', $fullname, '.xsl')}"/>
                    </xsl:for-each>
                </xsltPackages>
            </configuration>
        </xsl:result-document>
        
        <xsl:variable name="bootstrap-decl" as="element(xsl:stylesheet)">
            <xsl:element name="stylesheet" namespace="http://www.w3.org/1999/XSL/Transform">
                <xsl:attribute name="exclude-result-prefixes" select="'#all'"/>
                <xsl:attribute name="version" select="'3.0'"/>
                <xsl:for-each select="$steps">
                    <xsl:variable name="shortname" select="concat('step', position())"/>
                    <xsl:namespace name="{$shortname}" select="concat('urn:pipeline:', $shortname)"/>
                </xsl:for-each>
                <xsl:for-each select="$steps">
                    <xsl:variable name="filename" select="tokenize(base-uri(.), '/')[last()]" as="xs:string"/>
                    <xsl:variable name="fullname" select="substring-before($filename, '.xsl')"/>
                    <xsl:element name="use-package" namespace="http://www.w3.org/1999/XSL/Transform">
                        <xsl:attribute name="name" select="$fullname"/>
                        <xsl:attribute name="version" select="'1.0'"/>
                    </xsl:element>
                </xsl:for-each>
                
                <xsl:element name="template" namespace="http://www.w3.org/1999/XSL/Transform">
                    <xsl:attribute name="match" select="'/'"/>
                    <xsl:for-each select="$steps">
                        <xsl:variable name="input-pointer">
                            <xsl:choose>
                                <xsl:when test="position() eq 1">
                                    <xsl:value-of select="'.'"/>
                                </xsl:when>
                                <xsl:otherwise>
                                    <xsl:value-of select="concat('$result', position()-1)"/>
                                </xsl:otherwise>
                            </xsl:choose>
                        </xsl:variable>
                        <xsl:element name="variable" namespace="http://www.w3.org/1999/XSL/Transform">
                            <xsl:attribute name="name" select="concat('result', position())"/>
                            <xsl:attribute name="select" select="concat('step', position(), ':main(', $input-pointer, ')')"/>
                            <xsl:attribute name="as" select="'document-node()'"/>
                        </xsl:element>
                    </xsl:for-each>
                    <xsl:element name="sequence" namespace="http://www.w3.org/1999/XSL/Transform">
                        <xsl:attribute name="select" select="concat('$result', count($steps))"/>
                    </xsl:element>
                </xsl:element>
            </xsl:element>
        </xsl:variable>
        <xsl:result-document href="./bootstrap.xsl" indent="yes">
            <xsl:sequence select="$bootstrap-decl"/>
        </xsl:result-document>
    </xsl:template>
</xsl:stylesheet>

Excellent, thank you!