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authorKaz Kylheku <kaz@kylheku.com>2021-02-06 19:21:30 -0800
committerKaz Kylheku <kaz@kylheku.com>2021-02-06 19:21:30 -0800
commite6e9820a2060c70b20138b8f26a35e018c029954 (patch)
treeaa6474dec6841117f6749486744c1b027b6d5463
parentacdc6a768282aeb3d0e592481952233b08b3b838 (diff)
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matcher: predicate: document dot position of @avar.
* txr.1: The @avar variable may be in the dot position of the form, denoting application.
-rw-r--r--txr.114
1 files changed, 9 insertions, 5 deletions
diff --git a/txr.1 b/txr.1
index 312c7e04..e8fd0eeb 100644
--- a/txr.1
+++ b/txr.1
@@ -40680,22 +40680,25 @@ operator.
.synb
.mets >> @( function << arg *)
.mets >> @( function << arg * >> @ avar << arg *)
+.mets >> @( function << arg * . <> @ avar )
.mets >> @(@ rvar >> ( function << arg *))
.mets >> @(@ rvar >> ( function << arg * >> @ avar << arg *))
+.mets >> @(@ rvar >> ( function << arg * . <> @ avar ))
.syne
.desc
Whenever the operator position of a pattern consists of a symbol which is not
the name of a predicate operator, the expression denotes a predicate pattern,
-expected to conform to one of the first two syntax descriptions above. Whenever
+expected to conform to one of the first three syntax descriptions above. Whenever
the operator position of a pattern consists of a meta-variable, it is also a
-predicate pattern, expected to conform to one of the second two syntax
+predicate pattern, expected to conform to one of the three two syntax
descriptions.
The first form of the predicate pattern consists of a compound form consisting
of an operator and arguments. Exactly one of the arguments may be a pattern
variable
.meta avar
-("argument variable") which must be a bindable symbol. The role of
+("argument variable") which must be a bindable symbol. The pattern variable
+may also appear in the dot position, rather than as an argument. The role of
.meta avar
and the consequences of omitting it are described below.
@@ -40731,8 +40734,9 @@ inserted into the compound form, substituted in the position indicated by the
.mono
.meti >> @ avar
.onom
-variable. This form is then evaluated. If it yields true, then the
-match is successful, otherwise the match fails.
+variable, either an ordinary argument position or the dot position. This form
+is then evaluated. If it yields true, then the match is successful, otherwise
+the match fails.
If the
.meta avar