Parse EBNF: Difference between revisions
m
→{{header|Phix}}
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-- The rules that applies() has to deal with are:
-- {factors} - if rule[1] is not string, just apply one after the other,
--
-- but getting rid of it made the syntax tree much clearer)
-- {"terminal", "a1"} -- literal constants
-- {"or", <e1>, <e2>, ...} -- (any) one of n
-- {"repeat", <e1>} -- as per "{}" in ebnf
-- {"optional", <e1>} -- as per "
-- {"ident", <name>, idx} -- apply the sub-rule
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end if
end for</lang>
In real use, I would be tempted to use numeric literals rather than string tags in such structures, but the latter certainly make things ten times easier to debug, plus I got an instantly legible syntax tree dump (the bit just after "===>" below) practically for free.
{{out}}
<pre>
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