XSLT使用非常宽松的标准（EAD）处理XML

我花了一周的时间试图编写XSLT代码，以处理符合（非常宽松的）XML文档

EAD文档中的有用信息很难精确定位。不同的EAD文档可以在数据树的完全不同的部分放置相同的信息位。此外，在单个EAD文档中，同一标签可以在不同位置多次用于不同的信息。有关此示例，请参见此。这使得很难设计一个单独的XSLT文件来正确处理这些不同的文件

一般来说，问题可以描述为：

• 如何选择位于未知位置的特定EAD节点
• 而不会意外选择具有相同

  名称（）的不需要的节点

我终于把我需要的XSLT放在一起了，我认为最好在这里删除一个通用版本的代码，这样其他人就可以从中受益或改进它

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我很想用“EAD”标记这个问题，但我没有足够的代表。如果有人认为适当数量的代表会有用，请这样做。

首先快速描述解决方案，然后是代码

检查此EAD文档是否包含组件（子）记录（用

指定）。如果没有，我们就不必担心重复的EAD标签。标签仍然可以埋在任意包装下。要找到它们，请参见步骤3

如果存在子记录，请注意在处理其他标记之前不要处理

标记。要查找其他标记，请参阅步骤3，然后是步骤4以处理子记录

使用与之匹配的模板递归各种包装器，并在树下更远的任何元素节点上调用

apply template

我们现在正在处理一个子记录。重复步骤2（在处理此子记录的子项之前仔细处理所有其他标记），然后重复步骤4

下面是我提出的XSLT代码（通用版本）：

<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" encoding="ISO-8859-1" indent="yes"/>

<xsl:template match="/ead">
<records>
    <xsl:if test="//dsc">
        <!-- if there are <cXX> nodes, we'll handle the main record differently.
             <cXX> nodes are always found in the 'dsc' node, which contains nothing else -->
        <xsl:call-template name="carefully_process"/>
    </xsl:if>
    <xsl:if test="not(//dsc)">
        <record>
            <!-- Just process the existing nodes -->
            <xsl:apply-templates select="*"/>
        </record>
    </xsl:if>
</records>
</xsl:template>

<xsl:template name="carefully_process">
    <!-- first we'll process all the nodes for the main
         record. Then we'll call the child records -->
    <record>
        <!-- have to be careful not to process //archdesc/dsc yet -->
        <xsl:apply-templates select="*[not(self::archdesc)]"/>
        <xsl:apply-templates select="archdesc/*[not(self::dsc)]"/>

    <!-- Now we can close off the master record, -->
    </record>
    <!-- and process the child records -->
    <xsl:apply-templates select="/ead/archdesc/dsc"/>
</xsl:template>

<xsl:template match="dsc">
    <!-- Start processing the child records (we use for-each to get a good position() -->
    <xsl:for-each select="*[starts-with(name(),'c0') or starts-with(name(),'c1') or name() = 'c']">
        <xsl:apply-templates select=".">
            <!-- we pass the unittitle and unitid of the master record, so that child
                 records can be linked to it. We pass the position of the child so that
                 a unitid can be created if it doesn't exist -->
            <xsl:with-param name="partitle" select="normalize-space(/ead/archdesc/did/unittitle)"/>
            <xsl:with-param name="parid" select="normalize-space(/ead/archdesc/did/unitid)"/>
            <xsl:with-param name="pos" select="position()"/>
        </xsl:apply-templates>
    </xsl:for-each>
</xsl:template>

<!-- process child nodes -->
<xsl:template match="*[starts-with(name(),'c0') or starts-with(name(),'c1') or name() = 'c']" >
<xsl:param name="partitle"/>
<xsl:param name="parid"/>
<xsl:param name="pos"/>
    <!-- start this child record -->
    <record>

        <!-- EAD does not require a unitid, but my code does.
             If it doesn't exist, create it -->
        <xsl:if test="not(./did/unitid)">
            <atom name="unitid">
                <xsl:value-of select="$parid"/><xsl:text>-</xsl:text><xsl:value-of select="$pos"/>
            </atom>
        </xsl:if>

        <!-- get the level of this component -->
        <atom name="eadlevel">
            <xsl:value-of select="concat(translate(substring(@level,1,1),'abcdefghijklmnopqrstuvwxyz','ABCDEFGHIJKLMNOPQRSTUVWXYZ'),substring(@level,2))"/>
        </atom>

        <!-- Do *something* to attach this record to it's parent.
             Probably involves $partitle and $parid. For example: -->
        <ref>
            <atom name="unittitle"><xsl:value-of select="$partitle"/></atom>
            <atom name="unitid"><xsl:value-of select="$parid"/></atom>
        </ref>

        <!-- now process all the other nodes -->
        <xsl:apply-templates select="*[not(starts-with(name(),'c0') or starts-with(name(),'c1') or name() = 'c')]"/>

    <!-- finish this child record -->
    </record>

    <!-- prep the variables we'll need for attaching any child records (<cXX+1>) to this record -->
    <xsl:variable name="this_title">
        <xsl:value-of select="normalize-space(./did/unittitle)"/>
    </xsl:variable> 
    <xsl:variable name="this_id">
        <xsl:if test="./did/unitid">
            <xsl:value-of select="./did/unitid"/>
        </xsl:if>
        <xsl:if test="not(./did/unitid)">
            <xsl:value-of select="$parid"/><xsl:text>-</xsl:text><xsl:value-of select="$pos"/>
        </xsl:if>
    </xsl:variable>

    <!-- now process the children of this node -->
    <xsl:for-each select="*[starts-with(name(),'c0') or starts-with(name(),'c1') or name() = 'c']">
        <xsl:apply-templates select=".">
            <xsl:with-param name="partitle" select="$this_title"/>
            <xsl:with-param name="parid" select="$this_id"/>
            <xsl:with-param name="pos" select="position()"/>
        </xsl:apply-templates>
    </xsl:for-each>
</xsl:template>

<!-- these are usually just wrappers. Go one level deeper -->
<xsl:template match="descgrp|eadheader|revisiondesc|filedesc|titlestmt|profiledesc|archdesc|archdescgrp|daogrp|langusage|did|frontmatter">
    <xsl:apply-templates select="*"/>
</xsl:template>

<!-- below this point, add templates for processing specific EAD units
     of information. For example, the template might look like

<xsl:template match="titleproper">
    <atom name="titleproper">
        <xsl:value-of select="normalize-space(.)"/>
    </atom>
</xsl:template>
-->

<!-- instead of having a template for each EAD information unit, consider
     a generic template that handles them all the same way. For example:
-->
<xsl:template match="*">
    <atom>
        <xsl:attribute name="name"><xsl:value-of select="name()"/></xsl:attribute>
        <xsl:value-of select="normalize-space(.)"/>
    </atom>
</xsl:template>

</xsl:stylesheet>

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首先快速描述解决方案，然后是代码

检查此EAD文档是否包含组件（子）记录（用

指定）。如果没有，我们就不必担心重复的EAD标签。标签仍然可以埋在任意包装下。要找到它们，请参见步骤3

如果存在子记录，请注意在处理其他标记之前不要处理

标记。要查找其他标记，请参阅步骤3，然后是步骤4以处理子记录

使用与之匹配的模板递归各种包装器，并在树下更远的任何元素节点上调用

apply template

我们现在正在处理一个子记录。重复步骤2（在处理此子记录的子项之前仔细处理所有其他标记），然后重复步骤4

下面是我提出的XSLT代码（通用版本）：

<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" encoding="ISO-8859-1" indent="yes"/>

<xsl:template match="/ead">
<records>
    <xsl:if test="//dsc">
        <!-- if there are <cXX> nodes, we'll handle the main record differently.
             <cXX> nodes are always found in the 'dsc' node, which contains nothing else -->
        <xsl:call-template name="carefully_process"/>
    </xsl:if>
    <xsl:if test="not(//dsc)">
        <record>
            <!-- Just process the existing nodes -->
            <xsl:apply-templates select="*"/>
        </record>
    </xsl:if>
</records>
</xsl:template>

<xsl:template name="carefully_process">
    <!-- first we'll process all the nodes for the main
         record. Then we'll call the child records -->
    <record>
        <!-- have to be careful not to process //archdesc/dsc yet -->
        <xsl:apply-templates select="*[not(self::archdesc)]"/>
        <xsl:apply-templates select="archdesc/*[not(self::dsc)]"/>

    <!-- Now we can close off the master record, -->
    </record>
    <!-- and process the child records -->
    <xsl:apply-templates select="/ead/archdesc/dsc"/>
</xsl:template>

<xsl:template match="dsc">
    <!-- Start processing the child records (we use for-each to get a good position() -->
    <xsl:for-each select="*[starts-with(name(),'c0') or starts-with(name(),'c1') or name() = 'c']">
        <xsl:apply-templates select=".">
            <!-- we pass the unittitle and unitid of the master record, so that child
                 records can be linked to it. We pass the position of the child so that
                 a unitid can be created if it doesn't exist -->
            <xsl:with-param name="partitle" select="normalize-space(/ead/archdesc/did/unittitle)"/>
            <xsl:with-param name="parid" select="normalize-space(/ead/archdesc/did/unitid)"/>
            <xsl:with-param name="pos" select="position()"/>
        </xsl:apply-templates>
    </xsl:for-each>
</xsl:template>

<!-- process child nodes -->
<xsl:template match="*[starts-with(name(),'c0') or starts-with(name(),'c1') or name() = 'c']" >
<xsl:param name="partitle"/>
<xsl:param name="parid"/>
<xsl:param name="pos"/>
    <!-- start this child record -->
    <record>

        <!-- EAD does not require a unitid, but my code does.
             If it doesn't exist, create it -->
        <xsl:if test="not(./did/unitid)">
            <atom name="unitid">
                <xsl:value-of select="$parid"/><xsl:text>-</xsl:text><xsl:value-of select="$pos"/>
            </atom>
        </xsl:if>

        <!-- get the level of this component -->
        <atom name="eadlevel">
            <xsl:value-of select="concat(translate(substring(@level,1,1),'abcdefghijklmnopqrstuvwxyz','ABCDEFGHIJKLMNOPQRSTUVWXYZ'),substring(@level,2))"/>
        </atom>

        <!-- Do *something* to attach this record to it's parent.
             Probably involves $partitle and $parid. For example: -->
        <ref>
            <atom name="unittitle"><xsl:value-of select="$partitle"/></atom>
            <atom name="unitid"><xsl:value-of select="$parid"/></atom>
        </ref>

        <!-- now process all the other nodes -->
        <xsl:apply-templates select="*[not(starts-with(name(),'c0') or starts-with(name(),'c1') or name() = 'c')]"/>

    <!-- finish this child record -->
    </record>

    <!-- prep the variables we'll need for attaching any child records (<cXX+1>) to this record -->
    <xsl:variable name="this_title">
        <xsl:value-of select="normalize-space(./did/unittitle)"/>
    </xsl:variable> 
    <xsl:variable name="this_id">
        <xsl:if test="./did/unitid">
            <xsl:value-of select="./did/unitid"/>
        </xsl:if>
        <xsl:if test="not(./did/unitid)">
            <xsl:value-of select="$parid"/><xsl:text>-</xsl:text><xsl:value-of select="$pos"/>
        </xsl:if>
    </xsl:variable>

    <!-- now process the children of this node -->
    <xsl:for-each select="*[starts-with(name(),'c0') or starts-with(name(),'c1') or name() = 'c']">
        <xsl:apply-templates select=".">
            <xsl:with-param name="partitle" select="$this_title"/>
            <xsl:with-param name="parid" select="$this_id"/>
            <xsl:with-param name="pos" select="position()"/>
        </xsl:apply-templates>
    </xsl:for-each>
</xsl:template>

<!-- these are usually just wrappers. Go one level deeper -->
<xsl:template match="descgrp|eadheader|revisiondesc|filedesc|titlestmt|profiledesc|archdesc|archdescgrp|daogrp|langusage|did|frontmatter">
    <xsl:apply-templates select="*"/>
</xsl:template>

<!-- below this point, add templates for processing specific EAD units
     of information. For example, the template might look like

<xsl:template match="titleproper">
    <atom name="titleproper">
        <xsl:value-of select="normalize-space(.)"/>
    </atom>
</xsl:template>
-->

<!-- instead of having a template for each EAD information unit, consider
     a generic template that handles them all the same way. For example:
-->
<xsl:template match="*">
    <atom>
        <xsl:attribute name="name"><xsl:value-of select="name()"/></xsl:attribute>
        <xsl:value-of select="normalize-space(.)"/>
    </atom>
</xsl:template>

</xsl:stylesheet>

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