NAME
xmlif - conditional processing instructions for XML
SYNOPSIS
xmlif [attrib=value...]
DESCRIPTION
xmlif
filters XML according to conditionalizing markup. This can be useful for formatting one of several versions of an XML document depending on conditions passed to the command.
Attribute/value pairs from the command line are matched against the attributes associated with certain processing instructions in the document. The instructions are
<?xmlif if?>
and its inverse
<?xmlif if not?>,
<?xmlif elif?>
and its inverse
<?xmlif elif not?>,
<?xmlif else?>, and
<?xmlif fi?>.
Argument/value pairs given on the command line are checked against the value of corresponding attributes in the conditional processing instructions. An `attribute match' happens if an attribute occurs in both the command-line arguments and the tag, and the values match. An `attribute mismatch' happens if an attribute occurs in both the command-line arguments and the tag, but the values do not match.
Spans between
<?xmlif if?>
or
<?xmlif elif?>
and the next conditional processing instruction at the same nesting level are passed through unaltered if there is at least one attribute match and no attribute mismatch; spans between
<?xmlif if not?>
and
<?xmlif elif not?>
and the next conditional processing instruction are passed otherwise. Spans between
<?xmlif else?>
and the next conditional-processing tag are passed through only if no previous span at the same level has been passed through.
<?xmlif if?>
and
<?xmlif fi?>
(and their `not' variants) change the current nesting level;
<?xmlif else?>
and
<?xmlif elif?>
do not.
All these processing instructions will be removed from the output produced. Aside from the conditionalization, all other input is passed through untouched; in particular, entity references are not resolved.
Value matching is by string equality, except that "|" in an attribute value is interpreted as an alternation character. Thus, saying foo='red|blue' on the command line enables conditions red and blue. Saying color='black|white' in a tag matches command-line conditions color='black' and color='white'.
Here is an example:
Always issue this text.
<?xmlif if condition='html'?>
Issue this text if 'condition=html' is given on the command line.
<?xmlif elif condition='pdf|ps'?>
Issue this text if 'condition=pdf' or 'condition=ps'
is given on the command line.
<?xmlif else?>
Otherwise issue this text.
<?xmlif fi?>
Always issue this text.
AUTHOR
Eric S. Raymond <esr@snark.thyrsus.com>.
AUTHOR
Eric S. Raymond
""
Author.