Smart contract break for loop in smartpy

Question

I need to break a for loop in smartpy, but break does not work. Is there any other solution I could use?

Answer 1

Michelson is a functional language. break statements have no (clean) sense.

LOOP_LEFT is an approximation for break statements, but in smartpy you can do the following:

import smartpy as sp

class MyContract(sp.Contract):
  def __init__(self, **kargs):
    self.init(**kargs)

  @sp.entry_point
  def ep(self):
    stop = sp.local("stop", False)
    sp.while ~ stop.value:
      sp.if self.data.value > 5:
        stop.value = True
      sp.else:
        self.data.value += 1
        
    
@sp.add_test(name = "Example")
def test():
  scenario = sp.test_scenario()
  c1 = MyContract(value = 0)
  scenario += c1
  c1.ep()