XSLT – munging apostrophes

Escaping escapes can be a near impossible task with XSLT.

Here is the standard form of testing whether a string matches



<xsl:if

 test=”countryName=’USA’” >

  Name matches

</xsl:if>

What happens if the country name is People’s Republic of China instead?

You can’t use the apostrophe because the single quote is already used to delimit the string.
You can’t use double quotes around the string because it is already used to delimit the attribute
You can’t use the ' entity because it is converted to a single quote inside the attribute, so the attribute sees 'People's Republic of China' any way (which is an illegal expression).

Solution 1 – use string concatenation



<xsl:if

 test=”countryName=concat(‘People,’, &quot;&apos;&quot;, ‘s Republic of China’)” >

  Name matches

</xsl:if>

Solution 2 – use a variable



<xsl:variable name=”apos”>'</xsl:variable>

<xsl:if

 test=”countryName=concat(‘People,’, $apos, ‘s Republic of China’)” >

  Name matches

</xsl:if>

Solution 3 – thanks Jörn Horstmann



<xsl:variable name=”PRC”>People's Republic of China</xsl:variable>

<xsl:if

 test=”countryName=$PRC” >

  Name matches

</xsl:if>

About this entry

You’re currently reading “ XSLT – munging apostrophes ,” an entry on Chui's Counterpoint

Published:: 7.14.09 / 5pm

Category:: General

^love*encounter~flow 7.14.09 / 10pm

it is generally a bad idea to use a language (xslt here) which demands that you regularly put the very expressions that carry your programmatic intent into ‘escrow’ so to speak. i think it is bad language design. in this case, it is an outflow of the abuse of xml to express procedural content. look, the problems do not start at the apostrophe. they start when you have to put ‘if’ into pointy brackets. xml is so ‘stupid’, it can’t parse the word ‘if’, so to speak. i’ve seen shell scripts that call php that contains sql and so on, and i always tell people don’t but people won’t listen. using plain xml can be a pretty bad idea, but using xml to express a program that processes xml is worse. you want to have a decent, readable declarative language or a decent, readable procedural language for that purpose. xml is neither.

Jörn Horstmann 7.15.09 / 6am

How about using a variable to hold the string to compare, like this

People’s Republic of China

Name matches

Chui 7.15.09 / 9am

@love-encounter-flow XPath expressions inside XSLT is one of the warts in XSLT. Otherwise, we are so deeply invested already there was no choice but to workaround the problems. By the way, one saving grace of XSLT is that it’s actually a functional language, with no mutation allowed.

@Jörn yes that would work. I think WP swallowed your XML tags. I’ve included your solution in the post.

Marius Gedminas 7.20.09 / 11am

Can’t you use

test=”countryName="People’s Republic of China"”

test=’countryName=”People's Republic of China”‘

BTW would you please consider providing an RSS feed with full articles on Planet Python?

Yikes, the comment form interpreted my examples as HTML markup. Talk about metal-level confusion. I meant (and, since your blog has no ‘Preview’ button, can only hope that this’ll work):

and

Jarno Elovirta 7.20.09 / 6pm

Solution 4 – use apostrophes for attribute value

(WP ate the example)

Chui's Counterpoint

XSLT – munging apostrophes

Solution 1 – use string concatenation

Solution 2 – use a variable

Solution 3 – thanks Jörn Horstmann

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