Fuzion • Idioms • Idiom # 69: Seed random generator

Idiom # 69: Seed random generator

Random numbers generators in Fuzion are effects. To use a random number generator with a particular seed, we have to create an instance of simple_random_provider with the given seed and run code with this this effect in its environment. The standard library feature simple_random creates such a random provider with the given seed and installs it as the environment for running the code provided with the function parameter f.

Code

simple_random s f

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simple_random s f
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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What are effects?

Running Example

The following example provides a feature seed that executes a function f with in an environment with a seeded random number generator. For illustration, show_random is called in this context and also in the default random provider and an explicitly time seeded random provider:

ex69 is

  seed(s u64, f ()->unit) =>
    simple_random s f

  show_random (msg String) =>
    for i in 0..5 do
      say "$msg random is {random.next_u32 100}"

  show_random "default"

  seed 777 ()->
    show_random "seeded with 777"

  time_seeded_random (()->
    show_random "seeded with time")

  seed 777 ()->
    show_random "seeded with 777"

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ex69 is
  seed(s u64, f ()->unit) =>
    simple_random s f
  show_random (msg String) =>
    for i in 0..5 do
      say "$msg random is {random.next_u32 100}"
  show_random "default"
  seed 777 ()->
    show_random "seeded with 777"
  time_seeded_random (()->
    show_random "seeded with time")
  seed 777 ()->
    show_random "seeded with 777"
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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What are effects?

last changed: 2025-05-13

next: Idiom # 70: Use clock as random generator seed