JuliaConnectoR (version 1.1.4)

AccessMutate.JuliaProxy: Access or mutate Julia objects via proxy objects

Description

Apply the R operators $ and $<-, [ and [<-, [[ and [[<- to access or modify parts of Julia objects via their proxy objects. For an intuitive understanding, best see the examples below.

Usage

# S3 method for JuliaStructProxy
$(x, name)
# S3 method for JuliaStructProxy
$(x, name) <- value
# S3 method for JuliaProxy
[(x, ...)
# S3 method for JuliaProxy
[(x, i, j, k) <- value
# S3 method for JuliaSimpleArrayProxy
[(x, ...)
# S3 method for JuliaArrayProxy
[[(x, ...)
# S3 method for JuliaArrayProxy
[[(x, i, j, k) <- value
# S3 method for JuliaStructProxy
[[(x, name)
# S3 method for JuliaStructProxy
[[(x, name) <- value
# S3 method for JuliaArrayProxy
length(x)
# S3 method for JuliaArrayProxy
dim(x)

Arguments

x

a Julia proxy object

name

the field of a struct type, the name of a member in a NamedTuple, or a key in a Julia dictionary (type AbstractDict)

value

a suitable replacement value. When replacing a range of elements in an array type, it is possible to replace multiple elements with single elements. In all other cases, the length of the replacement must match the number of elements to replace.

i, j, k, ...

index(es) for specifying the elements to extract or replace

Details

The operators $ and [[ allow to access properties of Julia structs and NamedTuples via their proxy objects. For dictionaries (Julia type AbstractDict), $ and [[ can also be used to look up string keys. Fields of mutable structs and dictionary elements with string keys can be set via $<- and [[<-.

For AbstractArrays, the [, [<-, [[, and [[<- operators relay to the getindex and setindex! Julia functions. The [[ and [[<- operators are used to access or mutate a single element. With [ and [<-, a range of objects is accessed or mutated. The elements of Tuples can also be accessed via [ and [[.

The dimensions of proxy objects for Julia AbstractArrays and Tuples can be queried via length and dim.

Examples

if (FALSE) #'
# (Mutable) struct
juliaEval("mutable struct MyStruct
              x::Int
           end")

MyStruct <- juliaFun("MyStruct")
s <- MyStruct(1L)
s$x
s$x <- 2
s[["x"]]

# Array
x <- juliaCall("map", MyStruct, c(1L, 2L, 3L))
x
length(x)
x[[1]]
x[[1]]$x
x[[1]] <- MyStruct(2L)
x[2:3]
x[2:3] <- MyStruct(2L)
x

# Tuple
x <- juliaEval("(1, 2, 3)")
x[[1]]
x[1:2]
length(x)

# NamedTuple
x <- juliaEval("(a=1, b=2)")
x$a

# Dictionary
strDict <- juliaEval('Dict("hi" => 1, "hello" => 2)')
strDict
strDict$hi
strDict$hi <- 0
strDict[["hi"]] <- 2
strDict["howdy", "greetings"] <- c(2, 3)
strDict["hi", "howdy"]