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7.2 The pattern language
The syntax for <pattern> is:
<pattern> → Matches: <atom> the <atom>. | (kwote
<atom>) any expressioneq?
to<atom>
. | (and
<pat1> ... <patn>) if all of<pati>
match. | (or
<pat1> ... ...<patn>) if any of<pat1>
through<patn>
matches. | (not
<pat>) if<pat>
doesn't match. | (?
<predicate>) if<predicate>
is true. | (<pat1> ... <patn>) a list of n elements. Here,...
is a meta-character denoting a finite repetition of patterns. | <pat> ... a (possibly empty) repetition of<pat>
in a list. | #(<pat> ... <patn>) a vector of n elements. | #{<struct> <pat> ... } a structure. |?
<id> anything, and bindsid
as a variable. |?-
anything. |??-
any (possibly empty) repetition of anything in a list. |???-
any end of list.
Remark: and, or, not, check
and kwote
must be
quoted in order to be treated as literals. This is the only justification
for having the kwote
pattern since, by convention, any atom which is
not a keyword is quoted.
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