[Rd] Reference classes: accessor functions via 'getRefClass(...)$accessors(...)'
Hi there, I'd like to choose between an static and dynamic access of a reference class field, say 'a'. myObj - getRefClass(Blabla)$new() Static: myObj$a Dynamic: myObj$a.get() where the function retrieves the data from a database (or some other location), stores it to a buffer and optionally updates the static field value 'a'. I've set up such a method 'a.get()' where I can actually decide between static and dynamic runmode (so the method also wraps the call 'myObj$a' for the static runmode). Now I saw that setting up such accessor methods (get/set) is already done for me if I use 'getRefClass(Blabla)$accessors(.)'. I just don't understand what exactly I have to do there, because this results in an error: 'getRefClass(Blabla)$accessors(a)' Can anyone point me to the correct use of 'getRefClass(.)$accessors(.)'? Thanks a lot, Janko [[alternative HTML version deleted]] __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Reference classes: accessor functions via 'getRefClass(...)$accessors(...)'
Le 17/11/10 13:07, Janko Thyson a écrit :
Hi there,
I'd like to choose between an static and dynamic access of a reference
class field, say 'a'.
myObj- getRefClass(Blabla)$new()
Static: myObj$a
Dynamic: myObj$a.get() where the function retrieves the data
from a database (or some other location), stores it to a buffer and
optionally updates the static field value 'a'.
I've set up such a method 'a.get()' where I can actually decide between
static and dynamic runmode (so the method also wraps the call 'myObj$a' for
the static runmode).
Now I saw that setting up such accessor methods (get/set) is already done
for me if I use 'getRefClass(Blabla)$accessors(.)'. I just don't
understand what exactly I have to do there, because this results in an
error: 'getRefClass(Blabla)$accessors(a)'
Can anyone point me to the correct use of 'getRefClass(.)$accessors(.)'?
Thanks a lot,
Janko
Hi,
fields can either be data or active binding functionss. See
?makeActiveBinding for some example of active binding functions in their
original context.
Here is an example of a reference class that keeps its data in a file.
require( methods )
Foo - setRefClass( Foo,
fields = list(
file = character,
x = function(value){
if( missing( value ) ){
read.table( file )
} else{
write.table( value, file = file )
}
}
)
)
foo - Foo$new( file=/tmp/iris.txt )
foo$x - iris
foo$x
write.table( subset( iris, Petal.Length 2), file = /tmp/iris.txt )
foo$x
Does that help ?
Romain
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Re: [Rd] Reference classes: accessor functions via 'getRefClass(...)$accessors(...)'
Janko Thyson janko.thy...@ku-eichstaett.de writes: Hi there, I'd like to choose between an static and dynamic access of a reference class field, say 'a'. myObj - getRefClass(Blabla)$new() Static: myObj$a Dynamic: myObj$a.get() where the function retrieves the data from a database (or some other location), stores it to a buffer and optionally updates the static field value 'a'. I've set up such a method 'a.get()' where I can actually decide between static and dynamic runmode (so the method also wraps the call 'myObj$a' for the static runmode). Now I saw that setting up such accessor methods (get/set) is already done for me if I use 'getRefClass(Blabla)$accessors(.)'. I just don't understand what exactly I have to do there, because this results in an error: 'getRefClass(Blabla)$accessors(a)' Can anyone point me to the correct use of 'getRefClass(.)$accessors(.)'? It works for me: X - setRefClass(XXX, fields = list(a = character)) X$accessors(a) X # ... # Class Methods: #callSuper, export, getA, import, initFields, setA # ... accessors() convenience method creates setA and getA functions: x - X$new() x$getA #Class method definition for method getA() #function () #a #environment: 02a198c0 HTH, Vitalie. Thanks a lot, Janko [[alternative HTML version deleted]] __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Reference classes: accessor functions via 'getRefClass(...)$accessors(...)'
Thanks a lot for the comments! I'll give the serveral alternatives a try to see if it gets me what I want. Cheers, Janko -Ursprüngliche Nachricht- Von: Vitalie S. [mailto:spinuvit.l...@gmail.com] Gesendet: Mittwoch, 17. November 2010 13:51 An: Janko Thyson Cc: 'r-de...@r-project. org' Betreff: Re: Reference classes: accessor functions via 'getRefClass(...)$accessors(...)' Janko Thyson janko.thy...@ku-eichstaett.de writes: Hi there, I'd like to choose between an static and dynamic access of a reference class field, say 'a'. myObj - getRefClass(Blabla)$new() Static: myObj$a Dynamic: myObj$a.get() where the function retrieves the data from a database (or some other location), stores it to a buffer and optionally updates the static field value 'a'. I've set up such a method 'a.get()' where I can actually decide between static and dynamic runmode (so the method also wraps the call 'myObj$a' for the static runmode). Now I saw that setting up such accessor methods (get/set) is already done for me if I use 'getRefClass(Blabla)$accessors(.)'. I just don't understand what exactly I have to do there, because this results in an error: 'getRefClass(Blabla)$accessors(a)' Can anyone point me to the correct use of 'getRefClass(.)$accessors(.)'? It works for me: X - setRefClass(XXX, fields = list(a = character)) X$accessors(a) X # ... # Class Methods: #callSuper, export, getA, import, initFields, setA # ... accessors() convenience method creates setA and getA functions: x - X$new() x$getA #Class method definition for method getA() #function () #a #environment: 02a198c0 HTH, Vitalie. Thanks a lot, Janko [[alternative HTML version deleted]] __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
