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Left to Right Programming

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Re: Left to Right Programming

#251

Post by necovek »

jibal wrote: post #222
necovek wrote: post #207

Earlier quoted context omitted.

The same reason people are not flocking to the Lisps of the world: mathematical rigour and precision does not translate to higher legibility and understandability. Python's list /dict/set comprehensions are equivalent to typed for loops: where everyone complains about Python being lax with types, it's weird that one statement that guarantees a return type is now the target. Yet most other languages don't have the "pr…

"the target"? The OP complaint is not that the statement exists, but that the output expression comes before the context that establishes its meaning. This is not just a problem for autocomplete, but people often report difficulties understanding complex comprehensions. As for comprehensions themselves, ignoring that problem I find them a powerful and concise way to express a collection of computed values when that's…

That one is a generator[Any], and for others it could be set[Any], list[Any] or dict[Any]. You obviously don't get embedded type information, but you still do get the encapsulating type, which is better than an untyped for loop :)

I get that it's about how it's structured and ordered, but that is true for the "for..in" loops in every language as well: you first set the variable, and only then get the context — this just follows the same model as the for loops in the language, and it would be weird if it didn't.

Re: Left to Right Programming

#252

Post by xelxebar »

jibal wrote: post #219
danielPort9 wrote: post #21

Don’t know why python gets so much love. It’s a painful language as soon as more than one person is involved. What the author describes is just the tip of the iceberg

Failure to understand something is not a virtue. That it does get a lot of love strongly suggests that there are reasons for that. Of course it has flaws, but that alone doesn't tell us anything; only comparisons do. Create a comprehensive pro/con list and see how it fares. Then compare that to pro/con lists for other languages.

> That it does get a lot of love strongly suggests that there are reasons for that.

Reasons, sure, but whether those reasons correlate with things that matter is a different question altogether.

Python has a really strong on-ramp and, these days, lots of network effects that make it a common default choice, like Java but for individual projects. The rub is that those same properties—ones that make a language or codebase friendly to beginners—also add friction to expert usage and work.

> Failure to understand something is not a virtue.

This is what I want to say to all the Bash-haters that knee-jerk a "you should use a real language like Python" in the comments to every article that shows any Bash at all. It's a pet peeve of mine.

Re: Left to Right Programming

#253

Post by hnlmorg »

MonkeyClub wrote: post #245
hnlmorg wrote: post #231

Earlier quoted context omitted.

JavaScript has been a backend language long before the web was the dominant platform. And one of the, admittedly many, reasons why web technologies like Electron and React Native exist is because it’s easier to find JavaScript developers vs Kotin, Qt or whatever. So youre not wrong but you’re also downplaying the network effect that led to the web becoming dominant. And a part of that was because developers didn’t wa…

> JavaScript has been a backend language long before the web was the dominant platform. I don't think this holds. JavaScript was created as a frontend language specifically for web browsers. It wasn't until 2009 with the introduction of Node.js that JavaScript became a viable option for backend development. The web was already the dominant platform by then.

Actually I would say that was the turning point when the web started to become the dominant platform. Not the conclusion.

Before then it was Flash and native apps. Before then, smart phones weren’t common (eg the iPhone was just over a year old at that point) and the common idiom was to write native apps for Windows Mobile.

IE was still the dominant browser too, Firefox and WebKit were only starting to take over but we are still a long way from IE being displaced.

Electron didn’t exist so desktop app were still native and thus Linux was still a second class citizen.

It took roughly another roughly 2015 before the web because the dominant platform. But by 2005 you could already see the times were changing. It just took ages for technology to catch up. The advent of v8 and thus node and Electron, for that transition to “complete”.

Re: Left to Right Programming

#254

Post by Ultimatt »

juancn wrote: post #39

SQL shows it's age by having exactly the same problem. Queries should start by the `FROM` clause, that way which entities are involved can be quickly resolved and a smart editor can aid you in writing a sensible query faster. The order should be FROM -> SELECT -> WHERE, since SELECT commonly gives names to columns, which WHERE will reference. You could even avoid crap like `SELECT * FROM table`, and just write `FROM…

WITH and CTEs go some way to help with this, and the majority of queries are a lot better for that.

Re: Left to Right Programming

#255

Post by mrheosuper »

danielPort9 wrote: post #21

Don’t know why python gets so much love. It’s a painful language as soon as more than one person is involved. What the author describes is just the tip of the iceberg

I find python script written by C/C++ dev usually easier to understand than the one written in "Pythonic" style, even if it's longer and more verbose.

Re: Left to Right Programming

#256

Post by [deleted] »

balfirevic wrote: post #178
lackoftactics wrote: post #87

Earlier quoted context omitted.

This was a historical decision because SQL is a declarative language. I was confused for too long, I want to admit, about the SQL order: FROM/JOIN → WHERE → GROUP BY → HAVING → SELECT → ORDER BY → LIMIT As a self-taught developer, I didn't know what I was missing, but now the mechanics seem clear, and if somebody really needs to handle SELECT with given names, then he should probably use CTE: WITH src AS (SELECT * FR…

> This was a historical decision because SQL is a declarative language It would be equally declarative if FROM came first.

[deleted]

Re: Left to Right Programming

#257

Post by dragonwriter »

mrheosuper wrote: post #255
danielPort9 wrote: post #21

Don’t know why python gets so much love. It’s a painful language as soon as more than one person is involved. What the author describes is just the tip of the iceberg

I find python script written by C/C++ dev usually easier to understand than the one written in "Pythonic" style, even if it's longer and more verbose.

Are you, by any chance, a C/C++ dev?

Re: Left to Right Programming

#258

Post by jibal »

necovek wrote: post #251
jibal wrote: post #222

Earlier quoted context omitted.

"the target"? The OP complaint is not that the statement exists, but that the output expression comes before the context that establishes its meaning. This is not just a problem for autocomplete, but people often report difficulties understanding complex comprehensions. As for comprehensions themselves, ignoring that problem I find them a powerful and concise way to express a collection of computed values when that's…

That one is a generator[Any], and for others it could be set[Any], list[Any] or dict[Any]. You obviously don't get embedded type information, but you still do get the encapsulating type, which is better than an untyped for loop :) I get that it's about how it's structured and ordered, but that is true for the "for..in" loops in every language as well: you first set the variable, and only then get the context — this j…

"that is true for the "for..in" loops in every language as well"

No, not at all. The output expression is arbitrary ... it might be f(x, y, z) where all of those are set later. You're confusing the output expression with the loop variable, which is also stated in the comprehension and may or may not be the same as the output expression or part of it. "The same model as the for loops in the language", where the language includes Python, is the comprehension with the output expression moved from the beginning to the end. e.g., (bar(x) for x in foo()) is `for x in foo(): bar(x)`. More concretely: lst = [bar(x) for x in foo()] is functionally equivalent to lst = []; for x in foo(): lst.append(bar(x))

Again, "the output expression comes before the context that establishes its meaning." ... I thought that would be clear as day to anyone who is actually familiar with Python comprehensions.

P.S. I'm not going to respond to goalpost moving.

Re: Left to Right Programming

#259

Post by 9rx »

lackoftactics wrote: post #87
juancn wrote: post #39

SQL shows it's age by having exactly the same problem. Queries should start by the `FROM` clause, that way which entities are involved can be quickly resolved and a smart editor can aid you in writing a sensible query faster. The order should be FROM -> SELECT -> WHERE, since SELECT commonly gives names to columns, which WHERE will reference. You could even avoid crap like `SELECT * FROM table`, and just write `FROM…

This was a historical decision because SQL is a declarative language. I was confused for too long, I want to admit, about the SQL order: FROM/JOIN → WHERE → GROUP BY → HAVING → SELECT → ORDER BY → LIMIT As a self-taught developer, I didn't know what I was missing, but now the mechanics seem clear, and if somebody really needs to handle SELECT with given names, then he should probably use CTE: WITH src AS (SELECT * FR…

> This was a historical decision because SQL is a declarative language.

What do you mean? Both ALPHA (the godfather declarative database language created by Codd himself) and QUEL, both of which inspired SQL, put "FROM" first. Fun fact: SQL was originally known as SEQUEL, which was intended to be a wordplay on being a followup to QUEL.

Another commenter makes a good case that SQL ended up that way because it was trying to capture relational algebra notation (i.e. π₁(R), where π~select, ₁~column, R~table). Yet relational algebra is procedural, not declarative. Relational calculus is the declarative branch.

Although the most likely explanation remains simply that SEQUEL, in addition to being fun wordplay, also stood for Structured English Query Language. In English, we're more likely to say "select the bottle from the fridge", rather than "from the fridge, select the bottle". Neither form precludes declarative use.

Re: Left to Right Programming

#260

Post by PapstJL4U »

jibal wrote: post #227
kmoser wrote: post #101

Earlier quoted context omitted.

How is it supposed to compile if you've written something syntactically invalid? You can make the argument that the compiler could interpret it in (perhaps even arbitrary) valid way that constitutes a valid syntax, but that's almost worse: rather than being chided with compiler warnings, you now end up with code that compiles but executes indeterminately.

They didn't say "syntactically invalid".

> it shouldn't fail to compile just because you haven't finished writing it!

Syntactically invalid.

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