On Wed, May 19, 2021 at 2:37 PM Guido van Rossum wrote:

How well would something like this solve your issue?

import typing if typing.TYPE_CHECKING: class i8(int): pass else: from ctypes import c_int8 as i8

This approach has the benefit of avoiding a common problem with the c_int8 approach. a: i8 = i8(1) b: i8 = i8(2)

...

a + b TypeError: unsupported operand type(s) for +: 'c_byte' and 'c_byte'

I generally like it (as long as they're builtin/ergonomic and end users don't have to write the imports). But code such as: a: i8 = 1 b: i8 = 2 c: int = a + b generate errors that I would like to see go away

Or perhaps instead of the class definition use a type alias:

i8 = int

a: i8 = 10 b: i16 = 20 a = b # should generate an error but doesn't. -Arun

I have a fork of Typpete here: https://github.com/adsharma/Typpete/ that improves usability and commit 38068ca adds support for type checking fixed width integers. i: u8 = 300 # generates a type error General idea: use a type hierarchy such as: complex -> float -> int -> i64 -> i32 -> i16 -> i8 -> bool Things I'm looking to implement: * axioms for overflow, underflow detection and type inference * dependent and refinement types (which is basically a generalization of the above commit) * Requires/ensures for functions based on types. Looking for collaborators and people more familiar with z3 than I am. -Arun On Sun, May 23, 2021 at 11:06 AM Arun Sharma wrote:

https://github.com/adsharma/py2many/pull/254 implements some of this. Before transpiling, if we detect such overflows the transpiler errors out instead of relying on the target language compiler to report it.

TODO: Do something similar for underflows.

-Arun

On Wed, May 19, 2021 at 3:04 PM Arun Sharma wrote:

...

On Wed, May 19, 2021 at 2:37 PM Guido van Rossum wrote:

...

How well would something like this solve your issue?

import typing if typing.TYPE_CHECKING: class i8(int): pass else: from ctypes import c_int8 as i8

This approach has the benefit of avoiding a common problem with the c_int8 approach.

a: i8 = i8(1) b: i8 = i8(2)

...

...

a + b TypeError: unsupported operand type(s) for +: 'c_byte' and 'c_byte'

I generally like it (as long as they're builtin/ergonomic and end users don't have to write the imports). But code such as:

a: i8 = 1 b: i8 = 2 c: int = a + b

generate errors that I would like to see go away

...

Or perhaps instead of the class definition use a type alias:

i8 = int

a: i8 = 10 b: i16 = 20

a = b # should generate an error but doesn't.

-Arun