aossoa
Use a Structure of Arrays like an Array of Structures
Summary
| Latest Version | 0.1.0 |
|---|---|
| License | MIT |
| CI Status | Failing |
| Downloads | 0 |
| Last Indexed | 2026-09-02 07:20 |
Tags
Authors
- G. Bareigts
Installation
nimble install aossoa
choosenim install aossoa
git clone https://github.com/guibar64/aossoa
OS Compatibility
| Platform | Linux | macOS | Windows | FreeBSD | OpenBSD | NetBSD | Android | iOS | WASM | Embedded |
|---|---|---|---|---|---|---|---|---|---|---|
| aossoa | ✓ | ✓ | ✓ | - | - | - | - | - | - | - |
Dependencies
| Package | Version | Optional |
|---|---|---|
| nim >= | 1.2.0 | No |
Source
| Repository | https://github.com/guibar64/aossoa |
|---|---|
| Homepage | https://github.com/guibar64/aossoa |
| Registry Source | nimble_official |
README
Array of Structures to Structure of Arrays
This library allows to generate a SoA (Structure of Arrays) type from a Nim object, and use
syntax like a[i].field on it as if it were an AoS (Array of Structures).
Installation
With nimble:
nimble install aossoa
Or in a .nimble file put the line:
requires "aossoa"
Example
We start from an object MyObj
type
MyObj = object
field1: int
field2: float
var aos = @[MyObj(field1: 1, field2: 1.2), MyObj(field1: 2, field2: 2.1)]
echo aos[1].field2 # 2.1
and define an SoA
import aossoa
declareSoA(MyObj, MyObjSoA)
var soa: MyObjSoA
soa.setLen(2)
soa[1].field1 = 2
echo soa[1].field2, " ", soa.field2[1] # 2 2
The macro declareSoA expands conceptually to
type
MyObjSoA = object
field1: seq[int]
field2: seq[float]
template `[]`(s: MyObjSoA, i: int): IntermediateType
macro field1(temp: IntermediateType): int
macro field1(temp: IntermediateType): float
proc setLen(s: MyObjSoA, len: int)
## (re)sets all internal arrays
proc len(s: MyObjSoA, len: int)
## shared len of internal arrays
proc toMyObjSoA(s: MyObjSoA, a: sink openArray[MyObj])
## converts an array of MyObj to its SoA representation
proc toMyObj(temp: IntermediateType, a: sink openArray[MyObj])
## converts an array of MyObj to its SoA representation
Note that s[i].field is transformed at compile-time to s.field[i] `ÌntermediateType`` is “consumed” by the macros.
One can converts from Aos to SoA with the generated proc to${SoAType}:
let soa = toMyObjSoA(aos)
Due to the current implementation, “naked” indexing soa[i] is meaningless and gives a compile-time error on purpose.
To get a value of the type of the original object as one could expect wrap it like this:
echo soa[i].toMyObj
Note also that declareSoA exports the generated type to the world,
one can declareSoAPrivate to limit its scope to the current module
Currently, only plain non-generic objects are supported.
License
MIT