Author: larry
Date: Sat Mar 10 21:59:07 2007
New Revision: 14330


More fiddling with context().

Modified: doc/trunk/design/syn/S04.pod
--- doc/trunk/design/syn/S04.pod        (original)
+++ doc/trunk/design/syn/S04.pod        Sat Mar 10 21:59:07 2007
@@ -690,9 +690,9 @@
 Further contexts up the caller stack may be located by the selector
-that is built into the C<caller> function itself:
+that is built into the C<context> function itself:
-    caller({ .label eq 'LINE' }).leave(1,2,3);
+    context(0, { .label eq 'LINE' }).leave(1,2,3);
 By default the innermost dynamic scope matching the selection criteria
 will be exited.  This can be a bit cumbersome, so in the particular
@@ -729,7 +729,7 @@
 control structures, hence the sub's lexical scope was I<always>
 the innermost dynamic scope, so the preference to the lexical scope
 in the current sub was implicit.  For PerlĀ 6 we have to make this
-preference explicit.)  So this fallback is more like the C<caller>
+preference explicit.)  So this fallback is more like the C<context>
 form we saw earlier.
 Warnings are produced in PerlĀ 6 by throwing a resumable control

Modified: doc/trunk/design/syn/S06.pod
--- doc/trunk/design/syn/S06.pod        (original)
+++ doc/trunk/design/syn/S06.pod        Sat Mar 10 21:59:07 2007
@@ -1690,7 +1690,7 @@
 The C<caller> function is defined as
-    &caller ::= &context.assuming(1);
+    &caller ::= &context.assuming(1, *);
 so the preceding example can also be written:
@@ -1713,10 +1713,11 @@
     $ctx = context($i);    # $i'th caller's context
 The second argument is optional and is a matcher to apply against the
-context object.
+context object.  The first argument only counts matching contexts:
     $ctx = context(0, Method);           # nearest context that is method
     $ctx = context(1, Method);           # 2nd nearest context that is method
+    $ctx = context(1, Method).caller;    # caller of that 2nd nearest method
     $ctx = context(0, Block);            # nearest context that is block
     $ctx = context(2, Sub);              # 3rd nearest sub context
     $ctx = context(0, Block where { .label eq 'Foo' });
@@ -1729,20 +1730,27 @@
 which returns the context of the innermost Foo block in the lexical scope
 rather than the dynamic scope.
-The returned context object has the following methods:
+The returned context object supports at least the following methods:
+    .context
+    .caller
+    .lookup
-and basically anything else defined as C<$?NAME> there.  (XXX cop out)
+The C<.lookup> method provides access to the lexical namespace in effect
+at the given dynamic context's current position.  It may be used to look
+up ordinary lexical variables as well as special compiler variables such
+as C<$?PACKAGE>.  It must not be used to change any lexical variable
+that is not marked as C<< context<rw> >>.
 =head2 The C<want> function
 The C<want> function returns a C<Signature> object that contains information
 about the context in which the current block, closure, or subroutine was
+called.  The C<want> function is really just short for C<context(0).want>.
 As with normal function signatures, you can test the result of C<want> with a
 smart match (C<~~>) or a C<when>:

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