[Rd] reducing redundant work in methods package

[Michael Lawrence]

Note that setMethod() resolves .BasicFunsList in the methods namespace
directly when setting a method on a primitive. Somehow there should be
consistency between genericForPrimitive() and the check in setMethod().

Also, we can probably step away from the use of elNamed(), given that [[
now uses exact matching.

Have you tried patching methods to use .BasicFunsList directly as in
setMethod?


On Wed, Jan 21, 2015 at 10:41 AM, Peter Haverty <haverty.peter at gene.com>
wrote:

> Hi all,
>
> The function call series genericForPrimitive -> .findBasicFuns -> .findAll
> happens 4400 times while the GenomicRanges package is loading.  Each time
> .findAll follows a chain of environments to determine that the methods
> namespace is the only one that holds a variable called .BasicFunsList. This
> accounts for ~10% of package loading time. I'm sure there is some history
> to that design, but would it be possible shortcut this operation? Could
> .BasicFunsList be initialized in the methods namespace at startup and might
> genericForPrimitive just go straight there?
>
> Does anyone on the list know why it works this way?
>
> There are some other cases of seemingly redundant work, but this seems like
> an easy one to address.
>
> I have included some code below that was used to investigate some of the
> above.
>
> # Try this to count calls to a function
>
> .count <-  0; trace(methods:::.findBasicFuns,tracer=function() { .count <<-
> .count + 1 }); library(GenomicRanges); print(.count)
>
> # Try this to capture the input and output of a set of functions you wish
> to refactor
>
> .init_test_data_collection <- function(ns = asNamespace("methods")) {
>
>     funs = c("isClassUnion", "getClass", "genericForPrimitive",
> "possibleExtends", ".dataSlot", ".requirePackage", ".classEnv",
> "getClassDef", "outerLabels", ".getClassFromCache", "getFunction")
>
>     message(paste0("\nCollecting data for unit tests on ", paste(funs,
> collapse=", "), " ...\n"))
>
>     # Make env with list to hold test input/output
>
>     TEST_ENV <- new.env()
>
>     for (fname in funs) {
>
>         # Make placeholder for input/output for future runs of this
> function
>
>         TEST_ENV[[fname]] = list()  # Actually probably not necessary, will
> just be c(NULL, list(first result)) the first time
>
>         # Construct test version of function
>
>         unlockBinding(fname, ns)
>
>         fun = get(fname, envir=ns, mode="function")
>
>         funbody = deparse(body(fun))
>
>         newfun <- fun
>
>         newfun.body = c(
>
>             sprintf("fname = '%s'", fname),
>
>             "TEST_INFO = list()",
>
>             "TEST_INFO$input = mget(names(formals(fname)))",
>
>             c("realfun <- function()", funbody),
>
>             "TEST_INFO$output = realfun()",
>
>             "TEST_ENV[[fname]] = c(TEST_ENV[[fname]], list(TEST_INFO))",
>
>             "return(TEST_INFO$output)")
>
>         body(newfun) = as.call(c(as.name("{"),
> as.list(parse(text=newfun.body))))
>
>         assign(fname, newfun, envir=ns)
>
>     }
>
>     return(TEST_ENV)
>
> }
> # run code, print items in TEST_ENV
>
> The relevant code is in methods/R/BasicFunsList.R and
> methods/R/ClassExtensions.R
> Pete
>
> ____________________
> Peter M. Haverty, Ph.D.
> Genentech, Inc.
> phaverty at gene.com
>
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>
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