Cannot use rand at compile time

[bluenote10]

Example

import random
const x = rand(10)

Current Output

<NIM_ROOT>/lib/pure/random.nim(273, 8) Error: cannot evaluate at compile time: state

Expected Output

Compiles.

Additional Information

$ nim -v
Nim Compiler Version 0.20.99 [Linux: amd64]
Compiled at 2019-08-24
Copyright (c) 2006-2019 by Andreas Rumpf

git hash: ce7f29e8e6628df209ecebb566f9cefc14243aaf
active boot switches: -d:release

[mratsim]

What is your use-case?

You can use rand at compile-time by passing the state:

import random
var rng {.compileTime.} = initRand(0x1337DEADBEEF)
let foo {.compileTime.} = rng.rand(10)

I use this pattern in many of my libraries.

[bluenote10]

Just expected it to work as is, but yes that's a sensible work-around.

To clarify, using const is also possible with this pattern:

var rng {.compileTime.} = initRand(0x1337DEADBEEF)
const foo = rng.rand(10)