15 ms·

Sure, monads provide an elegant way to structure code with error conditions, but I don't see a problem with using simple assertions, throws, try-catch to enforc

Sure, monads provide an elegant way to structure code with error conditions, but I don't see a problem with using simple assertions, throws, try-catch to enforce invariants. Personally, I don't care about elegance as much as whether or not it works, as long as it is simple to use and maintain. I can return something like a Maybe/Either, or I can throw an exception - both approaches are fine by me if it forces the programmer to account for error cases.

pmichalina 8y ago
Throwing is a side effect breaking flow of control for no good reason. It’s takes you down the same path as all other spaghetti code. Not as much elegance as it is about purity. Minimizing side effects is the number one way to reduce bugs. It should be the number one guiding principle when creating out reliable software. Which means, you simply cannot use the primitive try catch or similar construct. Don’t break flow of control. Guide it to a terminal value instead. These days, when I see try-catch and if-else constructs (which is in most codebases) it’s clear there will be bugs over the life of the application. It’s fine, use them, but there is a world of greatness when you ditch these faulty constructs. Just like ditching OOP constructs. All built on false premises.
- platinumrad 8y ago
  This is what happens when you read just one chapter of Learn You a Haskell kids. Monads, not even once.
- carapace 8y ago
  You're correct, but you are arguing with fools. If they could understand what you're saying they would already. A few of them will get there eventually but software development will be a tire-fire, a cornucopia of bugs, for a while yet to come I think.
  - platinumrad 8y ago
    Nobody here is saying that monadic error handling isn't good (in case it wasn't abundantly clear, my comment was this thing that people call a "joke"). The issue is pmichalina flippantly disparaging asserts, one of the few good things left in this hell world: https://www.microsoft.com/en-us/research/publication/assessing-the-relationship-between-software-assertions-and-code-qualityan-empirical-investigation/ https://www.microsoft.com/en-us/research/publication/assessi...
    - carapace 8y ago
      It wasn't abundantly clear, but I'm often humorless. Sorry for being so crusty. I just found out that about a third of my professional career was essentially waste because I was too thick to adopt Prolog twenty years ago. It almost physically hurts to think about it. Anyway, I think OP's right about assertions being a code smell: an assertion is literally the place where you tell the machine you don't know exactly what you're doing, eh? I've been working towards an error-free mode of development, a combination of Dr. Margaret Hamilton's "Higher Order Software" concept that developed out of the Apollo 11 project with mathematical derivation of programs. I'm just about ready to "productize" it but I'm not going to market it to other developers. I'm going to sell it directly to consumers. They won't know enough to argue with the method, they'll just be able to use the computer to solve problems, I won't tell them that they are programmers. Bottom line: error-free software development methods have been available for decades but the industry tends to ignore them. In 2018 writing "assert", "throw" or "raise", etc. is a code smell: you are doing it worng. If I sound cranky it's because I am.
      - platinumrad 8y ago
        I hope you succeed, and I say that sincerely, but regardless of whether or not program synthesis should have been pursued more aggressively in the past, I'm not aware of any support for your statement that "error-free software development methods have been available for decades" for any reasonable definitions of "error-free" or "available". >Anyway, I think OP's right about assertions being a code smell: an assertion is literally the place where you tell the machine you don't know exactly what you're doing, eh? The whole point of the original article is that, today, the only thing keeping planes in the air is fault tolerance and lots of redundancy (see also: Erlang). Assertions are about humility and it's good to be humble. >In 2018 writing "assert", "throw" or "raise", etc. is a code smell: you are doing it worng. But somehow writing ">>=" isn't? On one hand you seem to suggest that error handling is bad because there shouldn't be errors (what about I/O? user error?) while on the other hand you seem to be defending the position that monadic error handling is a panacea.
- oftenwrong 8y ago
  If you application is interacting with the outside world, you will be dealing with side-effects, and sometimes error conditions will happen. For example, today I am working on a service that: - uses a database - calls external APIs - publishes and consumes from a message broker - interacts with local and remote filesystems over a variety of protocols All of these things entail error conditions, most of which throw exceptions in the corresponding libraries. Sometimes they are converted to Either/Maybe, and sometimes they are wrapped in "native" checked exceptions. The important bits: 1. The type system and compiler make sure the programmer has to deal with the error conditions at some point. From a programmer's perspective, a checked exception bubbling up the stack is not very different from returning a monadic object up the stack. 2. The core of the application is entirely pure. No exceptions (in both senses of the word). All side effects are pushed to the boundaries.

pmichalina 8y ago

Throwing is a side effect breaking flow of control for no good reason. It’s takes you down the same path as all other spaghetti code. Not as much elegance as it is about purity. Minimizing side effects is the number one way to reduce bugs. It should be the number one guiding principle when creating out reliable software. Which means, you simply cannot use the primitive try catch or similar construct. Don’t break flow of control. Guide it to a terminal value instead. These days, when I see try-catch and if-else constructs (which is in most codebases) it’s clear there will be bugs over the life of the application. It’s fine, use them, but there is a world of greatness when you ditch these faulty constructs. Just like ditching OOP constructs. All built on false premises.

platinumrad 8y ago
This is what happens when you read just one chapter of Learn You a Haskell kids. Monads, not even once.
carapace 8y ago
You're correct, but you are arguing with fools. If they could understand what you're saying they would already. A few of them will get there eventually but software development will be a tire-fire, a cornucopia of bugs, for a while yet to come I think.
- platinumrad 8y ago
  Nobody here is saying that monadic error handling isn't good (in case it wasn't abundantly clear, my comment was this thing that people call a "joke"). The issue is pmichalina flippantly disparaging asserts, one of the few good things left in this hell world: https://www.microsoft.com/en-us/research/publication/assessing-the-relationship-between-software-assertions-and-code-qualityan-empirical-investigation/ https://www.microsoft.com/en-us/research/publication/assessi...
  - carapace 8y ago
    It wasn't abundantly clear, but I'm often humorless. Sorry for being so crusty. I just found out that about a third of my professional career was essentially waste because I was too thick to adopt Prolog twenty years ago. It almost physically hurts to think about it. Anyway, I think OP's right about assertions being a code smell: an assertion is literally the place where you tell the machine you don't know exactly what you're doing, eh? I've been working towards an error-free mode of development, a combination of Dr. Margaret Hamilton's "Higher Order Software" concept that developed out of the Apollo 11 project with mathematical derivation of programs. I'm just about ready to "productize" it but I'm not going to market it to other developers. I'm going to sell it directly to consumers. They won't know enough to argue with the method, they'll just be able to use the computer to solve problems, I won't tell them that they are programmers. Bottom line: error-free software development methods have been available for decades but the industry tends to ignore them. In 2018 writing "assert", "throw" or "raise", etc. is a code smell: you are doing it worng. If I sound cranky it's because I am.
    - platinumrad 8y ago
      I hope you succeed, and I say that sincerely, but regardless of whether or not program synthesis should have been pursued more aggressively in the past, I'm not aware of any support for your statement that "error-free software development methods have been available for decades" for any reasonable definitions of "error-free" or "available". >Anyway, I think OP's right about assertions being a code smell: an assertion is literally the place where you tell the machine you don't know exactly what you're doing, eh? The whole point of the original article is that, today, the only thing keeping planes in the air is fault tolerance and lots of redundancy (see also: Erlang). Assertions are about humility and it's good to be humble. >In 2018 writing "assert", "throw" or "raise", etc. is a code smell: you are doing it worng. But somehow writing ">>=" isn't? On one hand you seem to suggest that error handling is bad because there shouldn't be errors (what about I/O? user error?) while on the other hand you seem to be defending the position that monadic error handling is a panacea.
oftenwrong 8y ago
If you application is interacting with the outside world, you will be dealing with side-effects, and sometimes error conditions will happen. For example, today I am working on a service that: - uses a database - calls external APIs - publishes and consumes from a message broker - interacts with local and remote filesystems over a variety of protocols All of these things entail error conditions, most of which throw exceptions in the corresponding libraries. Sometimes they are converted to Either/Maybe, and sometimes they are wrapped in "native" checked exceptions. The important bits: 1. The type system and compiler make sure the programmer has to deal with the error conditions at some point. From a programmer's perspective, a checked exception bubbling up the stack is not very different from returning a monadic object up the stack. 2. The core of the application is entirely pure. No exceptions (in both senses of the word). All side effects are pushed to the boundaries.