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authordkf <donal.k.fellows@manchester.ac.uk>2009-03-26 10:43:47 (GMT)
committerdkf <donal.k.fellows@manchester.ac.uk>2009-03-26 10:43:47 (GMT)
commit17fa409b18efb7df83ed36881fad903c1bd43670 (patch)
treeab209f60f7bbefbcb82131838da1f4076f5e2255 /doc
parent0b1bed54ab922c6a8d0f9a3471a1115ddad907da (diff)
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Some small improvements to the last example
Diffstat (limited to 'doc')
-rw-r--r--doc/coroutine.n20
1 files changed, 13 insertions, 7 deletions
diff --git a/doc/coroutine.n b/doc/coroutine.n
index ad9fddd..08662c8 100644
--- a/doc/coroutine.n
+++ b/doc/coroutine.n
@@ -4,7 +4,7 @@
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
-'\" RCS: @(#) $Id: coroutine.n,v 1.1 2009/03/25 10:26:11 dkf Exp $
+'\" RCS: @(#) $Id: coroutine.n,v 1.2 2009/03/26 10:43:47 dkf Exp $
'\"
.so man.macros
.TH coroutine n 8.6 Tcl "Tcl Built-In Commands"
@@ -78,24 +78,30 @@ for {set i 0} {$i < 10} {incr i} {
.CE
.PP
This example demonstrates the use of coroutines to implement the classic Sieve
-of Eratosthenes algorithm for finding prime numbers.
+of Eratosthenes algorithm for finding prime numbers. Note the creation of
+coroutines inside a coroutine.
.PP
.CS
proc filterByFactor {source n} {
\fByield\fR [info coroutine]
while 1 {
- set x [$source]
+ set x [\fI$source\fR]
if {$x % $n} {
\fByield\fR $x
}
}
}
\fBcoroutine\fR allNumbers apply {{} {while 1 {\fByield\fR [incr x]}}}
-set c allNumbers
+\fBcoroutine\fR eratosthenes apply {c {
+ \fByield\fR
+ while 1 {
+ set n [\fI$c\fR]
+ \fByield\fR $n
+ set c [\fBcoroutine\fR prime$n filterByFactor $c $n]
+ }
+}} allNumbers
for {set i 1} {$i <= 20} {incr i} {
- set n [$c]
- puts "prime#$i = $n"
- set c [\fBcoroutine\fR prime$i filterByFactor $c $n]
+ puts "prime#$i = [\fIeratosthenes\fR]"
}
.CE
.SH "SEE ALSO"