fork(x-1) leads to error Unbound variable 'x-1'. But fork(x+(-1)) works

[2lian]

Description

fork(x-1) leads to error Unbound variable 'x-1'.. But fork(x+(-1)) works.

To Reproduce

def pow_down(number, power):
  bend x=power:
    when x>1:
      mult = number * fork(x-1)
    else:
      mult = number
  return mult

def main:
  return pow_down(2, 10)

Returns:

Errors:
In definition 'pow_down':
  Unbound variable 'x-1'.

Expected behavior

This piece of code works and outputs 1024, I would expect both to work or both to throw an error:

def pow_down(number, power):
  bend x=power:
    when x>1:
      mult = number * fork(x+(-1))
    else:
      mult = number
  return mult

Desktop

• OS: WSL (Ubuntu 22.04)
• CPU: Intel i5-12600K
• GPU: GTX 1080Ti
• Cuda Version 12.3

Additional context

Please ignore my shitty sequential code.

[imaqtkatt]

Bend variable names follow this regular expression: [A-Za-z0-9_.-/]+. If you type x - 1 the code will work as expected.

A var_name-num is actually a special variable that is used to access a predecessor of the matching number in the last case of a switch case:

def main:
  switch num = 4:
    case 0:
      return 0
    case 1:
      return 1
    case 2:
      return num-2

[2lian]

Oh yes sorry I just read this part of the doc because this error came up again: https://github.com/HigherOrderCO/Bend/blob/main/docs/syntax.md#variables . 10 minute after after opening the issue, I noticed that it was a dumb question ...

Anyway, thanks a lot for taking your time to explain!

[developedby]

I'll improve the error message since this is a very common situation