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Unexpected behavior with R reference class objects
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| ## It's a real pain to deal with deep-linking to Gists (eg sourcing raw code), so I'm working on this | |
| ## in GitHub proper: | |
| ## https://github.com/maptracker/RandomR/blob/master/RefClassHeadaches.R | |
| ## Quickly source this code: | |
| ## source("https://gist.github.com/maptracker/00f2c18383e844c3f4a0886b7897ceb7/raw/532410cf19b4df6f9949bdc9ec1dd0e9d13ef898/RefClassHeadaches.R") | |
| hr <- paste(rep("- ", 20), collapse = "") | |
| hr <- paste("\n", hr) | |
| message(hr) | |
| message("Trying to comprehend object methods in Reference Class objects") | |
| message(hr) | |
| bar <- setRefClass("bar",fields = list( x = "integer")) | |
| ## This will not work | |
| bar$methods( | |
| initialize = function(..., x = 12L) { | |
| ## We have the "right" class here: | |
| message(.self$show()) | |
| message("About to have an error") | |
| levelOne("Inside Init") | |
| message(" I never get here!") | |
| callSuper(..., x = x ) | |
| }) | |
| ## Shouldn't the method below "be available" to the object? | |
| bar$methods( levelOne = function ( msg = "Hi") { | |
| message("bar$levelOne() sez: ",msg) }) | |
| try ({ | |
| if (exists("b")) rm(b) | |
| b <- bar() | |
| message("Object was not created, we will never get here") | |
| b$levelOne("My L1 bar Message") | |
| }) | |
| message(hr) | |
| bip <- setRefClass("bip",fields = list( x = "integer")) | |
| ## It does not help to callSuper() first | |
| bip$methods( | |
| initialize = function(..., x = 12L) { | |
| ## If we callSuper() first, the $x field gets properly set, | |
| ## but we still do not have any knowledge of the $levelOne() | |
| ## method | |
| callSuper(..., x = x ) | |
| message(.self$show()) | |
| message("About to have an error") | |
| levelOne("Inside Init") | |
| message(" I never get here!") | |
| }) | |
| ## Shouldn't the method below "be available" to the object? | |
| bip$methods( levelOne = function ( msg = "Hi") { | |
| message("bip$levelOne() sez: ",msg) }) | |
| try ({ | |
| if (exists("bp")) rm(bp) | |
| bp <- bip() | |
| message("Object was not created, we will never get here") | |
| bp$levelOne("My L1 bip Message") | |
| }) | |
| message(hr) | |
| bipk <- setRefClass("bipk",fields = list( x = "integer")) | |
| ## Define levelOne() "before" initialize(), which makes everything | |
| ## happy. The only change from the "bip" objects is that levelOne() is | |
| ## a few lines higher in the source code. | |
| bipk$methods( levelOne = function ( msg = "Hi") { | |
| message("bipk$levelOne() sez: ",msg) }) | |
| bipk$methods( | |
| initialize = function(..., x = 12L) { | |
| message("For some reason defining the *object* method 'earlier' works!") | |
| levelOne("Inside Init") | |
| message(" Success!") | |
| callSuper(..., x = x ) | |
| }) | |
| try({ | |
| if (exists("bk")) rm(bk) | |
| bk <- bipk() | |
| bk$levelOne("My L1 bipk Message") | |
| }) | |
| message(hr) | |
| ## Defining the methods in a monolithic (and ugly) block works ok | |
| bork <- setRefClass("bork", | |
| fields = list( x = "integer"), | |
| methods = list(initialize = function(..., x = 12L) { | |
| message("Setting methods in setRefClass() works") | |
| levelOne("Inside Init") | |
| message(" Success!") | |
| callSuper(..., x = x ) | |
| }, levelOne = function ( msg = "Hi") { | |
| message("bork$levelOne() sez: ",msg) }) | |
| ) | |
| try({ | |
| if (exists("bo")) rm(bo) | |
| bo <- bork() | |
| bo$levelOne("My L1 bork Message") | |
| }) | |
| message(hr) | |
| baz <- setRefClass("baz",fields = list( x = "integer")) | |
| ## Directly referencing .self$levelOne() works | |
| baz$methods( | |
| initialize = function(..., x = 12L) { | |
| message("Explicit reference to '.self' is also ok") | |
| .self$levelOne("Inside Init") | |
| message(" Success!") | |
| callSuper(..., x = x ) | |
| }) | |
| baz$methods( levelOne = function ( msg = "Hi") { | |
| message("baz$levelOne() sez: ",msg) }) | |
| try({ | |
| if (exists("bz")) rm(bz) | |
| bz <- baz() | |
| bz$levelOne("My L1 baz Message") | |
| }) | |
| message(hr) | |
| jaz <- setRefClass("jaz",fields = list( x = "integer")) | |
| ## "Peeking at .self$levelOne (with no "()"!!) somehow "preloads" the | |
| ## method, which somehow allows it to then be called without .self | |
| ## ??!? | |
| jaz$methods( | |
| initialize = function(..., x = 12L) { | |
| message("Just *checking* the method allows it to be called w/o .self") | |
| chk <- .self$levelOne # Not actually "doing" anything, "just looking" | |
| levelOne("Inside Init") # WHY DOES THIS NOW WORK?? | |
| message(" Success!") | |
| callSuper(..., x = x ) | |
| }) | |
| jaz$methods( levelOne = function ( msg = "Hi") { | |
| message("jaz$levelOne() sez: ",msg) }) | |
| try({ | |
| if (exists("jz")) rm(jz) | |
| jz <- jaz() | |
| jz$levelOne("My L1 jaz Message") | |
| }) | |
| ## Trying (and failing) to replicate issues happening outside of | |
| ## initialize(). In a (much) more complex object, this paradigm is not | |
| ## working at all (ie zz$levelTwo() is failing because $levelOne | |
| ## appears to be suffering from the "apparently not yet defined" | |
| ## problems reflected in the examples above)... | |
| message(hr) | |
| zaz <- setRefClass("zaz",fields = list( x = "integer")) | |
| zaz$methods( levelTwo = function ( msg = "Bye") { | |
| levelOne(paste("From levelTwo:", msg)) }) | |
| zaz$methods( levelOne = function ( msg = "Hi") { | |
| message("zaz$levelOne() sez: ",msg) }) | |
| try({ | |
| if (exists("zz")) rm(zz) | |
| zz <- zaz() | |
| zz$levelOne("My L1 zaz Message") | |
| zz$levelTwo("My L2 zaz Message") | |
| }) | |
| message(hr) |
> version
_
platform x86_64-pc-linux-gnu
arch x86_64
os linux-gnu
system x86_64, linux-gnu
status
major 3
minor 3.1
year 2016
month 06
day 21
svn rev 70800
language R
version.string R version 3.3.1 (2016-06-21)
nickname Bug in Your Hair
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