Translate SmartPy expression into Michelson

Question

import smartpy as sp

def logic(data):
    t = sp.TRecord(x=sp.TNat, y=sp.TNat, z=sp.TNat)
    unpacked = sp.unpack(data, t).open_some(message="Can't unpack!!")
    
    sp.result(unpacked.x + unpacked.y)
    
i_need_this = sp.build_lambda(logic)

How will I be able to convert SmartPy functions into Michelson code?

Context: I need this lambda in michelson so that I am able to pass it as an argument to an entrypoint in typescript (with taquito).

Answer 1

I re-paste the answer given on Telegram.

Using the CLI:

scenario.show(lambda x:x+1, compile=True)

This creates a file when called from the CLI with the compilation target (named something like step_000_expression.tz).

Using the web browser:

import smartpy as sp

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

    @sp.entry_point
    def f(self, p):
        sp.compute(p)

@sp.add_test(name = "Test")
def test():
    scenario = sp.test_scenario()
    c1 = MyContract()
    scenario += c1
    c1.f(lambda x:x+1)

(the sp.compute is almost irrelevant, it’s only there to avoid SmartPy complaining that p is unused)

Example here.

With a longer function you can do

def my_function(params):
    sp.set_type(params, sp.TRecord(a=sp.TNat, b=sp.TNat, c=sp.TNat))
    sp.result(params.a + params.b + params.c)

c1.f(my_function)

Example here.