xslt_to_ruby_reference.md

XSLT to Ruby

Moving from XML stylesheets to ruby can seem daunting, but actually it's fun!

• if, choose, when, otherwise
• Equals and Other Comparisons
• for-each()
• substring-after()
• substring-before()
• text()

If, choose, when, otherwise

if

<xsl:if test="condition">[your code here]</xsl:if>

Ruby

if condition
  [your code here]
end

# or if you want to live dangerously

[your code here] if condition

choose, when, otherwise

<xsl:choose>
  <xsl:when test="condition">...</xsl:when>
  <xsl:when test="condition2">...</xsl:when>
  <xsl:otherwise>...</xsl:otherwise>
</xsl:choose>

Ruby

if condition1
  ...
elsif condition2
  ...
else
  ...
end

Leave out elsif if you have no second condition

Equals and Other Comparisons

Common Ruby operators:

Name	Ruby
Equal	==
Not equal	!=
Less than, etc	<, <=
Greater than, etc	>, >=

|

Ruby

<xsl:variable name="fish" select="//some_xpath/text()"/>
<xsl:if test="$fish = 'trout'">[some code]</xsl:if>

fish = @xml.get_text("//some_xpath")
if fish == "trout"
  [some code]
end

for-each()

Given this xml snippet:

<people>
  <author @role="primary">
    <persName><lastName>Cather</lastName></persName>
  </author>
  <author @role="editor">
    <persName><lastName>Somebody</lastName></persName>
  </author>
</people>

<xsl:for-each select="//author">
  <xsl:value-of select="persName/lastName"/>
  <xsl:text> the </xsl:text>
  <xsl:value-of select="@role">
<xsl:for-each>

authors = @xml.xpath("//author")
authors.each do |author|
  lastname = author.get_text("persName/lastName")
  role = author["role"]
  puts "#{lastname} the #{role}"
end

substring-after()

substring-after("Something|like this", "|")

"Something|like this".split("|").last

Note: .last will work great if your string only separated into two pieces. If you split on something like spaces and you need one of the words from the middle, you will have to work harder to get it out.

substring-before()

Xpath:

substring-before(string, '[Willa Cather]')

Ruby

string.split([Willa Cather]).first

Alternatively, you can use regex

string.split(/regex goes here/).first

text()

Xpath

ele/text()

Ruby

ele.text