I posted Congressional Roll Call Vote – Accessibility Issues earlier today to deal with some accessibility issues noticed by @XQuery with my color coding.
Today we are going to start at the top of the boring original roll call vote and work our way down using XQuery.
Be forewarned that the XQuery you see today we will be shortening and cleaning up tomorrow. It works, but its not best practice.
You will need to open up the source of the original roll call vote to see the elements I select in the path expressions.
Here is the XQuery that is the goal for today:
xquery version “3.0”;
declare boundary-space preserve;
<html>
<head></head>
<body>
<h2 align=”center”>FINAL VOTE RESULTS FOR ROLL CALL {string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//rollcall-num)} </h2><strong>{string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//rollcall-num)}</strong> {string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//action-date)} {string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//action-time)} <br/>
<strong>Question:</strong> {string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//vote-question)} <br/>
<strong>Bill Title:</strong> {string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//vote-desc)}
</body>
</html>
The title of the document we obtain with:
<h2 align=”center”>FINAL VOTE RESULTS FOR ROLL CALL {string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//rollcall-num)} </h2>
Two quick things to notice:
First, for very simple documents like this one, I use “//” rather than writing out the path to the rollcall-num element. I already know it only occurs once in each rollcall document.
Second, when using direct element constructors, the XQuery statements are enclosed by “{ }” brackets.
The rollcall number, date and time of the vote come next (I have introduced line breaks for readability):
<strong>{string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//rollcall-num)}</strong>
{string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//action-date)}
{string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//action-time)} <br/>
If you compare my presentation of that string and that from the original, you will find the original has slightly more space between the items.
Here is the XSLT for that spacing:
<xsl:if test=”legis-num[text()!=’0′]”><xsl:text> </xsl:text><b><xsl:value-of select=”legis-num”/></b></xsl:if>
<xsl:text> </xsl:text><xsl:value-of select=”vote-type”/>
<xsl:text> </xsl:text><xsl:value-of select=”action-date”/>
<xsl:text> </xsl:text><xsl:value-of select=”action-time”/><br/>
Since I already had white space separating my XQuery expressions, I just added to the prologue:
declare boundary-space preserve;
The last two lines:
<strong>Question:</strong> {string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//vote-question)} <br/>
<strong>Bill Title:</strong> {string(doc(“http://clerk.house.gov/evs/2015/roll705.xml”)//vote-desc)}
Are just standard queries for content. The string operator extracts the content of the element you address.
Tomorrow we are going to talk about how to clean up and shorten the path statements and look around for information that should be at the top of this document, but isn’t!
PS: Did you notice that the vote totals, etc., are written as static data in the XML file? Curious isn’t it? Easy enough to generate from the voting data. I don’t have an answer but thought you might.