3 ms·

Not all functions can produce an error. If you add two arbitrary precision integers, you're not getting an error.

by beojan 8y ago

amelius 8y ago
So (+) would be defined as adding its operands, except if one of them is an error (in which case the result would be an error).
- jjaredsimpson 8y ago
  Either is a sum type. What if I don't want that. It's not about handling errors per se, but modeling the type.
  - amelius 8y ago
    Yes, I understand. But by "implicitly" I really meant that. You don't see the type, only the compiler does. The programmer only sees the non-error part of the type (the "Right" part of Either).
    - jjaredsimpson 8y ago
      How could this work? I specify an interface to an api. C Foo(A a) = ... Someone then provides me with some not-A error value. What should I do? What do you mean by implicit.
  - KirinDave 8y ago
    > Either is a sum type. What if I don't want that. Product types work as well, if you want. But unless your return type is a monoid (or like, a semilattice maybe?) then you're going to end up with Sum Types somewhere. The vast, vast majority of software engineers and students work with sum types every day and they're totally fine with them. Most languages implicitly sum many values with null.
KirinDave 8y ago
Unless you're running in a multi-threaded environment or run out of memory?
- lauritzsh 8y ago
  These sounds like exceptions rather than errors to me. Difference being, exceptions truly are exceptional and not anticipated; like running out of memory. How do you even handle that? Would probably let it crash and restart (Erlang model). Errors is something you anticipate can happen, such as getting 4xx-5xx back from the server and know what to do in those cases. Then it's fair to say that you definitely can't get an error by adding two numbers.
  - KirinDave 8y ago
    > How do you even handle that? You request a smaller block of memory? Not everyone is always requesting the minimum they need right now. > Would probably let it crash and restart (Erlang model) The Erlang model is to let a partial failure trigger a less complex part of the system to resume that logic based on a strategy. > Then it's fair to say that you definitely can't get an error by adding two numbers. I mean, you can also accept garbage back, I guess?

Not all functions can produce an error. If you add two arbitrary precision integers, you're not getting an error.

by beojan 8y ago

Not all functions can produce an error. If you add two arbitrary precision integers, you're not getting an error.

So (+) would be defined as adding its operands, except if one of them is an error (in which case the result would be an error).

jjaredsimpson 8y ago
Either is a sum type. What if I don't want that. It's not about handling errors per se, but modeling the type.
- amelius 8y ago
  Yes, I understand. But by "implicitly" I really meant that. You don't see the type, only the compiler does. The programmer only sees the non-error part of the type (the "Right" part of Either).
  - jjaredsimpson 8y ago
    How could this work? I specify an interface to an api. C Foo(A a) = ... Someone then provides me with some not-A error value. What should I do? What do you mean by implicit.
- KirinDave 8y ago
  > Either is a sum type. What if I don't want that. Product types work as well, if you want. But unless your return type is a monoid (or like, a semilattice maybe?) then you're going to end up with Sum Types somewhere. The vast, vast majority of software engineers and students work with sum types every day and they're totally fine with them. Most languages implicitly sum many values with null.

KirinDave 8y ago

Unless you're running in a multi-threaded environment or run out of memory?

lauritzsh 8y ago
These sounds like exceptions rather than errors to me. Difference being, exceptions truly are exceptional and not anticipated; like running out of memory. How do you even handle that? Would probably let it crash and restart (Erlang model). Errors is something you anticipate can happen, such as getting 4xx-5xx back from the server and know what to do in those cases. Then it's fair to say that you definitely can't get an error by adding two numbers.
- KirinDave 8y ago
  > How do you even handle that? You request a smaller block of memory? Not everyone is always requesting the minimum they need right now. > Would probably let it crash and restart (Erlang model) The Erlang model is to let a partial failure trigger a less complex part of the system to resume that logic based on a strategy. > Then it's fair to say that you definitely can't get an error by adding two numbers. I mean, you can also accept garbage back, I guess?