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Left to Right Programming

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Re: Left to Right Programming

#161

Post by astrange »

kmoser wrote: post #101
astrange wrote: post #46

Earlier quoted context omitted.

I agree with this, but it leads to another principle that too many languages violate - it shouldn't fail to compile just because you haven't finished writing it! It should fail in some other non-blocking way. But some languages just won't let you do that, because they put in errors for missing returns or unused variables.

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.

Well I don't literally mean finished as in you haven't finished typing it. Although that's possible too - whitespace languages like Python tend to just work since they don't have end brackets, I suppose.

But you could have a compiled language where errors were limited to the function when possible, like by emitting asserts.

Re: Left to Right Programming

#162

Post by doug_durham »

ivanjermakov wrote: post #138
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 think because it's forgiving and the first language for many people, so they just stick to easy they know.

It's my 18th language and I prefer it over the alternatives. If I need to write an app I'll use Swift. If I need to do some web work I'll switch to TypeScript. To get work done it's Python all the way.

Re: Left to Right Programming

#164

Post by sn9 »

lazarovitch wrote: post #116
bvrmn wrote: post #109

Author picked up a quite convenient example to show methods/lambda superiority. I prefer list/set/dict comprehensions any day. It's more general, doesn't require to know a myriad of different methods (which could not exists for all collections, PHP and JS are especially bad with this) and easily extendable to nested loops. Yes it could be `[for line in text.splitlines() if line: for word in line.split(): word.upper()…

I'm a big fan of Python syntax, but really comprehensions don't make any sense to me efficiency wise (even for readability). Python syntax would become perfect with filter() and map() :')

With judicious use of generators, and with itertools [0] when needed, they can be quite efficient for not much effort.

And these are flexible tools that you can take with you across projects.

[0] https://docs.python.org/3/library/itertools.html

Re: Left to Right Programming

#165

Post by ivanjermakov »

doug_durham wrote: post #162
ivanjermakov wrote: post #138

Earlier quoted context omitted.

I think because it's forgiving and the first language for many people, so they just stick to easy they know.

It's my 18th language and I prefer it over the alternatives. If I need to write an app I'll use Swift. If I need to do some web work I'll switch to TypeScript. To get work done it's Python all the way.

Agree. At some point grasping a new language takes hours and it makes sense to use it for tasks it excels at.

Re: Left to Right Programming

#166

Post by noosphr »

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

Because everything that tries to fix it is just as painful in different ways.

I've had the displeasure of working in codebases using the style of programming op says is great. It's pretty neat. Until you get a chain 40 deep and you have to debug it. You either have to use language features, like show in pyspark, which don't scale when you need to trace a dozen transformations, or you get back to imperative style loops so you can log what's happening where.

Re: Left to Right Programming

#167

Post by taeric »

jayd16 wrote: post #159
taeric wrote: post #148

Earlier quoted context omitted.

No, this assumes you know what you want for a query. Which, seems largely fair? Like, how would you send this question to someone? Or how would you expect it to be sent to you? If your boss doesn't tell you from what table they want some data, do you just not answer? And sure, there could be ambiguities here. But these are not really fixed by listing the sources first? You would almost certainly need to augment the s…

If my boss asks me for a zip code, I'm going to ask "for what?" If they ask for "address for a customer" I can go to the customer table and look up what FKs are relevant and collect all possible data and then narrow down from there.

I'd assume they would ask for "aggregate sales by month to zip codes," or some such. Which, you'd probably get from a reporting table, and not bother trying to do the manual aggregate over transactional data. (That is, OLAP versus OLTP is a very real divide that you can't wave away.)

Realistically, I strongly suspect you could take this argument either direction. If you have someone making a query where they are having to ask "what all tables could I start from?" you are in for some pain. Often the same data is reachable from many tables, and you almost certainly have reasons for taking certain paths to get to it. Similarly, if they should want "person_name", heaven help them.

Such that, can you contrive scenarios where it makes sense to start the query from the from clause? Sure. My point is more that you almost certainly have the entire query conceptualized in your mind as you start. You might not remember all of the details on how some things are named, but the overall picture is there. Question then comes down to if one way is more efficient than the other? I have some caveats that this is really a thing hindered by the order of the query. We don't have data, of course, and are arguing based on some ideas that we have brought with us.

So, would I be upset if the order was reversed? Not at all. I just don't expect that would actually help much. My memory is using query builders in the past where I would search for "all tables that have customer_id and order_id in them" and then, "which table has customer_id and customer_address" and then... It was rarely (ever?) the name of the table that helped me know which one to use. Rather, I needed the ones with the columns I was interested in.

Re: Left to Right Programming

#168

Post by taeric »

debazel wrote: post #158
taeric wrote: post #156

Earlier quoted context omitted.

Often times you don't know it is possible to get some data without consulting the table? Worse, you probably need to consult the views that have been made by any supporting DB team before you go off and build your own rollups. Unless you like not taking advantage of any aggregate jobs that are running nightly for reporting. And to be clear, I'm all for complaining about the order of a select statement, to a very larg…

> How do you know the tables you want so well, but you don't know the columns you are going to ask for? Simply because there are a lot more columns than there are tables. Of course, I sometimes forget the exact table name as well. However, this is mostly not an issue as the IDE knows all table names before anything has been entered. By simply entering `FROM user`, the autocomplete will list all tables that contain `u…

But "more columns than there are tables" is also why I put the thing about, "the total number of columns most people would need autocomplete for are rather limited?" I could see an argument on how this mattered back at the origin of SQL, but today? It is entirely conceivable that you can autocomplete the column names with it updating the from as necessary for the columns you have selected. You could then tab to the from and pick alternative tables with natural joins prefilled between the tables. With very minimum effort.

I actually seem to recall this was done in some of the early dedicated SQL tools. It is rather amusing how much we handicap ourselves by not using some things older tools built.

Re: Left to Right Programming

#169

Post by paradox460 »

dleeftink wrote: post #49
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…

PSQL (and PRQL) use this ordering, and a similar pipe/arrow notation has recently been added to BigQuery. Check out the DuckDB community extensions: [0]: https://duckdb.org/community_extensions/extensions/psql.html [1]: https://duckdb.org/community_extensions/extensions/prql.html

And in elixir land we've had similar pipes and composition through ecto, for the major rdbms

Re: Left to Right Programming

#170

Post by Izkata »

taeric wrote: post #106
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…

My main caveat here, is that often the person starting a select knows what they want to select before they know where to select it from. To that end, having autocomplete for the sources of columns is far far more useful than autocomplete for columns from a source. I will also hazard a guess that the total number of columns most people would need autocomplete for are rather limited? Such that you can almost certainly…

Likewise when skimming code, having the attributes on the left and details on the right makes it much easier to see the data flow in the larger program - it's the same order as "var foo = bar()".
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