Martin Morgan wrote:
[...]
## Attempt two -- initialize
setClass("Element",
representation=representation(conn="file"))
setMethod(initialize, "Element", function(.Object, ..., conn=file()) {
callNextMethod(.Object, ..., conn=conn)
})
new("Element")
## oops, connection created but not closed; gc() closes (eventually)
## but with an ugly warning
## > gc()
## used (Mb) gc trigger (Mb) max used (Mb)
## Ncells 717240 38.4 1166886 62.4 1073225 57.4
## Vcells 37333395 284.9 63274729 482.8 60051033 458.2
## > gc()
## used (Mb) gc trigger (Mb) max used (Mb)
## Ncells 715906 38.3 1166886 62.4 1073225 57.4
## Vcells 37335626 284.9 63274729 482.8 60051033 458.2
## Warning messages:
## 1: closing unused connection 3 ()
setClass("ElementX", contains="Element")
## oops, two connections opened (!)
yes, that's because of the nonsense double call to the initializer while
creating a subclass. the conceptual bug in the s4 system leads to this
ridiculous behaviour in your essentially correct and useful pattern.
vQ
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