How to fold by a tag a group of selected (neighbor) tags with XSLT1?

Question

I have a set of sequential nodes that must be enclosed into a new element. Example:

  
    cccc
    aaaa<         


        

Answer 1

In XSLT 1.0 the standard technique to handle this sort of thing is called Muenchian grouping, and involves the use of a key that defines how the nodes should be grouped and a trick using generate-id to extract just the first node in each group as a proxy for the group as a whole.

This achieves the grouping you're after, but just like your non-general solution it doesn't preserve the indentation and the whitespace text nodes between the a and b elements, i.e. it will give you

  cccc
  
    aaaa
    1111
  
  
    bbbb
    2222
  

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Note that if you were able to use XSLT 2.0 then the whole thing becomes one for-each-group: