[Rd] Problem calling $ inside a $ method

From: Seth Falcon <sfalcon_at_fhcrc.org>
Date: Mon, 07 May 2007 21:59:57 -0700


I wonder if this will make it through the spam filters given the subject line.

I'm seeing the following when trying to call a dollar method inside of a dollar method.

    setClass("Foo", representation(d="list"))
[1] "Foo"

    f <- new("Foo", d=list(bob=1, alice=2))

## We can call dollar at this level and it works as expected

    `$`(f, "bo")
[1] 1

    `$`(f, "al")
[1] 2

## So set a method on Foo that does this

    setMethod("$", "Foo", function(x, name) `$`(x_at_d, name))
[1] "$"

## But it doesn't work. Why?

    NULL     f$al
    NULL ## Here is a hackish workaround.

    setMethod("$", "Foo", function(x, name)

              eval(substitute(x_at_d$FOO, list(FOO=name))))
[1] "$"

[1] 1

[1] 2

Other suggestions for workarounds? Is this a bug?

+ seth

Seth Falcon | Computational Biology | Fred Hutchinson Cancer Research Center

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Received on Tue 08 May 2007 - 05:03:33 GMT

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