Hi Folks,

My question is about writing XSLT in a functional programming style.

My understanding is that a litmus test for whether a program is written in a functional style is whether it can be executed in any order.

Consider this problem: convert a sequence of N numbers into a cumulative sequence, in which each number is the sum of the previous numbers.

Here is a loop that solves the problem:

<xsl:for-each select="Number">
       <xsl:value-of select="sum((., preceding-sibling::Number))" />
</xsl:for-each>

Can this code be executed in any order?

Suppose the loop is unraveled into a series of<xsl:value-of> statements. If those statements are evaluated in arbitrary order then the output would not be in the desired sequence. Thus, I conclude, this loop is not written in a functional style. Do you agree?

How would the problem be solved in a functional style?

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