[XSL-LIST Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: For-each adds whitespace per iteration: why?
Eliot, Note that if, inside the for-each, you use xsl:value-of instead of xsl:sequence (thereby. as I understand it, generating text nodes instead of strings), the spaces disappear. I suppose this works because by emitting text nodes, we step around the concatenation rules. Cheers, Wendell Wendell Piez | http://www.wendellpiez.com XML | XSLT | electronic publishing Eat Your Vegetables _____oo_________o_o___ooooo____ooooooo_^ On Fri, Jan 10, 2014 at 12:05 PM, Eliot Kimber <ekimber@xxxxxxxxxx> wrote: > In the context of writing an XSLT to generate DTD syntax from RNGs (for > DITA 1.3) I discovered that for-each results in whitespace being emitted > for each iteration. This came as a surprise. Reading the spec it says, > under clause 7, Repetition: > > "For each item in the input sequence, evaluating the sequence constructor > <http://www.w3.org/TR/xslt20/#dt-sequence-constructor> produces a sequence > of items (see 5.7 Sequence Constructors > <http://www.w3.org/TR/xslt20/#sequence-constructors>). These output > sequences are concatenated; if item Q follows item P in the sorted > sequence, then the result of evaluating the sequence constructor with Q as > the context item is concatenated after the result of evaluating the > sequence constructor with P as the context item. The result of the > xsl:for-each <http://www.w3.org/TR/xslt20/#element-for-each> instruction > is the concatenated sequence of items.b > > I understand "These output sequences are concatenatedb to mean that string > concatenation rules are applied, which explains the white space. > > My question: why is for-each defined in this way? It came as a surprise to > me that constructing a string using for-each resulted in extra and > unwanted whitespace (I have a function that generates strings of blanks of > a specified length so I can do indention of the DTD components and I was > getting off-by-one results in my formatted DTD output). > > > I tested this with this little XSLT transform: > > <?xml version="1.0" encoding="UTF-8"?> > <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" > xmlns:xs="http://www.w3.org/2001/XMLSchema" > xmlns:xd="http://www.oxygenxml.com/ns/doc/xsl" > exclude-result-prefixes="xs xd" > version="2.0"> > > <xsl:output method="text"/> > > <xsl:template name="test-for-each"> > <xsl:variable name="strings" select="('one', 'two', 'three', 'four')"/> > value-of $strings=<xsl:value-of select="$strings"/> > for $str in $strings return concat('/', $str, '/')=<xsl:sequence > select="for $str in $strings return concat('/', $str, '/')"/> > string-join($strings, '')=<xsl:sequence select="string-join($strings, > '')"/> > for-each over strings: "<xsl:for-each select="$strings"> > <xsl:sequence select="concat('/',.,'/')"/> > </xsl:for-each>" > </xsl:template> > > </xsl:stylesheet> > > > > Which produces this output using Saxon 9.5.1.2: > > value-of $strings=one two three four > for $str in $strings return concat('/', $str, '/')=/one/ /two/ /three/ > /four/ > string-join($strings, '')=onetwothreefour > for-each over strings: "/one/ /two/ /three/ /four/" > > > > I see that the for-each result is consistent with the flowr expression. > > Is my analysis correct that the only way to construct a string with no > extra whitespace using a loop is to use string-join() as in my test case? > > For my DTD-generation application that would mean using the for-each loop > to construct a sequence of strings and then using string-join on the > sequence to avoid additional whitespace. Of course I can simply account > for the space inserted by the concatenation and get the correct indention > and keep my code a bit simpler. > > Cheers, > > Eliot > > -- > Eliot Kimber > Senior Solutions Architect > "Bringing Strategy, Content, and Technology Together" > Main: 512.554.9368 > www.reallysi.com > www.rsuitecms.com
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