MutatePlainDataArray.jl

Enable mutating immutable plain data fields using aref wrapper, allowing mutating immutable plain data fields using the following syntax:

    aref(v)[i].a.b[] = val

The nested fields can be accessed using either the field name, or the field index with getproperty. The wrapped vector must implement the strided arrays interface and must have isbitstype element type.

Examples:

julia> using MutatePlainDataArray

julia> a = [1, 2, 3];

julia> aref(a)[1][] = 4
4

julia> a
3-element Vector{Int64}:
 4
 2
 3

julia> b = [(;tup=(1, 2.5), s=4), (;tup=(2, 4.5), s=5)];
 
julia> aref(b)[1].tup.:2[] = Inf
Inf

julia> b
2-element Vector{@NamedTuple{tup::Tuple{Int64, Float64}, s::Int64}}:
 (tup = (1, Inf), s = 4)
 (tup = (2, 4.5), s = 5)

julia> (aref(b)[2].:1).:1[] *= 100
200

julia> b
2-element Vector{@NamedTuple{tup::Tuple{Int64, Float64}, s::Int64}}:
 (tup = (1, Inf), s = 4)
 (tup = (200, 4.5), s = 5)

The mutation provided by this package is

• Efficient. Under the hood, the mutation is achieved by pointer load/store, where the address offset is known at type inference time.
• Safe. Compile-time type check is enforced. Reference to the original vector is obtained to prevent garbage collection. Bounds check is performed unless @inbounds is used. This package is inspired by and acts as a safer counterpart to UnsafePointers.jl.