14.8.2.2 Generating XML tags for each level

Check each index entry for colons: level separators that indicate a new index level. When a colon is encountered, close the XML element for the current level, and increment the level number:

	[ProcIXtext]
1	<$$IXlevel = 1>
2	<$_while ($$IXtext length)>
3	<index<$$IXlevel>>	Opening XML tag
4	<$$IXpart = ($$IXtext before ":")>
5	<$$IXpart>	Text
6	<$$IXpart = ($$IXtext after ":")>
7	<$$IXtext = $$IXpart>
8	</index<$$IXlevel>>	Closing XML tag
9	<$$IXlevel++>
10	<$_endwhile>

The unary length operator in line 2 gets the length of the preceding value of variable $$IXtext, so the <$_while> expression works correctly; see:

§28.6.4 Using control structures in expressions

§28.6.5 Specifying substrings in expressions.

Assignment statements by default do not produce output, so only the value of the $$IXpart variable on line 5 actually ends up as content between the XML <indexn> tags, which are output on line 3 and line 8; see:

§28.3.2 Assigning values to macro variables

§28.6.3 Displaying expression results in output.

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