English Language & Usage: Multi-Layered Discourse Room

tchrist

02:00

@Cerberus Yeah, reges are second-class citizens there.

Mr. Shiny and New 安宇

@tchrist well, "devs" then.

Cerberus

@tchrist Well, I didn't make a mistake so much as I just couldn't find how if thingies worked.

Mr. Shiny and New 安宇

@Cerberus It's not uncommon to have to declare which modules you want to use.

Cerberus

But how was I to know, when I saw a Python Regex example and somehow it didn't work for me?

Mr. Shiny and New 安宇

It allows for evolution of the libraries. You could have two modules that provide the same functions

Cerberus

02:01

Autohotkey has libraries.

But it includes things like Regex.

tchrist

@Mr.ShinyandNew安宇 Regexes aren't first class citizens in the language, which produces inefficiencies and surprises.

Cerberus

@tchrist Or did you mean it was a mistake of Python's?

tchrist

@Cerberus Yes.

Cerberus

To use tabs to mark off if thingies.

OK.

tchrist

I meant it was a mistake of Python's, not of yours.

Cerberus

02:02

phew

Mr. Shiny and New 安宇

@Cerberus You don't need to use tabs. You just need to use consistent spacing.

Cerberus

Consistent?

The space bar works too?

Mr. Shiny and New 安宇

I think so

Cerberus

I see.

tchrist

It does.

It still bites.

Cerberus

02:04

Another thing I like about Autohotkey is that capitalisation doesn't matter.

tchrist

That's a bug to most of us.

Cerberus

But it wouldn't bother you.

Mr. Shiny and New 安宇

My understanding is that you can indent with any number of spaces or tabs, as long as each line is indented the same as above, or, if a new block is required, indented more, or if a block is ended, indented the same as the previous block.

tchrist

It would bother me.

Mr. Shiny and New 安宇

@Cerberus That would bother me.

Cerberus

02:05

Surely you wouldn't want to be using Var and var at the same time? It would be confusing.

Mr. Shiny and New 安宇

Several languages use capital letters to denote classes and lower case to denote variables.

So I can say Cat cat = new Cat();

Cat is the type. cat is the variable.

tchrist

Genus species.

Cerberus

You can still do that using the appropriate Autohotkey syntax?

How would I find that in the Autohotkey docs? "Class"?

Mr. Shiny and New 安宇

@Cerberus possibly

tchrist

@Cerberus The online Perl regex docs are really quite extensive, and that isn't even talking about the guts, just the user-level stuff. Plus the Camel's regex chapter is more than 100 pages long, which is followed by a 40-page Unicode chapter that is tightly coupled in many places to regexes.

Cerberus

02:07

> class ClassName extends BaseClassName
{
InstanceVar := Expression
static ClassVar := Expression

class NestedClass
{
...
}

Method()
{
...
}

Property[] ; Brackets are optional
{
get {
return ...
}
set {
return ... := value
}
}
}

Example code from the doc.

tchrist

Bad indentation.

Cerberus

@tchrist Great!

@tchrist It is properly indented in the doc.

Does this look inconvenient or confusing to you?

Just curious.

Mr. Shiny and New 安宇

I disapprove of the use of :=

Cerberus

Why?

But that's unrelated to capitalisation.

You can also use just = in Autohotkey.

Mr. Shiny and New 安宇

because value assignment is a constantly done thing and I hate typing needless crap

tchrist

02:11

Huffman coding

In computer science and information theory, a Huffman code is a particular type of optimal prefix code that is commonly used for lossless data compression. The process of finding and/or using such a code proceeds by means of Huffman coding, an algorithm developed by David A. Huffman while he was a Ph.D. student at MIT, and published in the 1952 paper "A Method for the Construction of Minimum-Redundancy Codes". The output from Huffman's algorithm can be viewed as a variable-length code table for encoding a source symbol (such as a character in a file). The algorithm derives this table from t...

Because you type assignment a bazinga times more often than you do equality tests.

So it makes sense for the more common operation to be shorter.

Cerberus

You can use either = or :=

> The latter method is preferred by many due to its greater clarity, and because it supports an expression syntax nearly identical to that in many other languages.

Mr. Shiny and New 安宇

@Cerberus identical to many other languages, each of which I hate

tchrist

I use Huffman optimization on my identifier names. Stuff I don't want people to use I make hard to type. :)

Cerberus

Haha.

Well, then you can use the = method.

Mr. Shiny and New 安宇

@Cerberus See, that, to me, is a warning that the language is poorly designed.

Cerberus

02:14

It is designed with convenience in mind.

Oftentimes, different people want different methods.

tchrist

@Mr.ShinyandNew安宇 Were you also damaged by a Pascal or Modula or for the love of all that's holy Ada compiler as a small child?

Mr. Shiny and New 安宇

@tchrist Turing

Cerberus

Mr. Shiny and New 安宇

and PL/SQL

tchrist

yuck

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

02:15

Fortran?

Mr. Shiny and New 安宇

I turned down a better-paying job because it would be all PL/SQL all the time.

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ thankfully no.

tchrist

Well of course you did. My mother wouldn't even put up with it.

Cerberus

Anyway, does the class thingy shown in the example look inconvenient to you, just because it doesn't depend on capitalisation?

tchrist

"Depend on capitalization"?

Mr. Shiny and New 安宇

@Cerberus Well, not really, except that then I can't do the Cat cat = new Cat(); thing, and also it encourages people to write stuff with no capitals.

tchrist

02:17

CONSTANT_SYMBOLS Global_Variables local_ones

Cerberus

I don't really understand what your catty thing does, but doesn't Autohotkey provide for a way to do that in the example?

tchrist

That's what capitalization means to me. Violate that and I won't touch your code.

Cerberus

Oh, I see.

Mr. Shiny and New 安宇

@tchrist granted you can still do that in case-insensitive languages, but when I write a module that calls your constant_symbols and the compiler allows it.....

tchrist

I use capitalization meaningfully.

Mr. Shiny and New 安宇

02:19

@Cerberus Sure, I can still write the same program, but I can no longer use Cat and cat as two different symbols

I'd have to write something like Cat aCat = new Cat();

because even though the capitalization means something to me, it doesn't to the compiler.

tchrist

And yet if ($if > @if) { &if } is not something that will endear you to most people.

Mr. Shiny and New 安宇

@tchrist Sure, it can be abused.

In Java you can have a method with the same name as a constructor.

it's a good way to get beat up after work.

Cerberus

@Mr.ShinyandNew安宇 Okay, so that doesn't look terribly inconvenient? Or is it?

In Autohotkey, variables are global by default.

Mr. Shiny and New 安宇

@Cerberus that's a bug

Cerberus

In function definitions, they're local by default.

tchrist

02:22

That's a bug.

Cerberus

How so?

Mr. Shiny and New 安宇

variables should be local to the nearest enclosing scope

tchrist

Scope should not be context sensitive.

Cerberus

Isn't a function definition a scope?

We're probably talking about the same thing.

Mr. Shiny and New 安宇

I guess AHK is a little like a bash script

tchrist

02:23

The scope of a variable should not change depending on whether you use it in a function or not.

Mr. Shiny and New 安宇

if you declare your variables at the start of your script, they're global to the script

Cerberus

If I write a function like this:

Mr. Shiny and New 安宇

@tchrist I think he's referring to where it's declared

tchrist

Hm.

I'm not sure he declares things. It might be like shell scripts.

Cerberus

> function() {
teststring = blah
}

Mr. Shiny and New 安宇

02:24

oh right.

Cerberus

Then teststring will be local to the function.

Mr. Shiny and New 安宇

that kind of variable declaration.

that entire paradigm is a bug.

tchrist

That's not really declaration.

Mr. Shiny and New 安宇

variables should have to be declared.

tchrist

Right.

Cerberus

02:25

Ah, but that would be very inconvenient.

tchrist

What if there were a variable in a surrounding scope called teststring?

@Cerberus Are you sure you don't know FORTRAN? :)

Cerberus

@tchrist I don't know.

Mr. Shiny and New 安宇

@Cerberus It saves you from a world of pain if your code is ever changed after the first time you use it.

Cerberus

How so?

Mr. Shiny and New 安宇

It's so important to good coding practices that Javascript added the ability to require that variables be declared before use.

@Cerberus well, let's say you have a function with a variable blah.

tchrist

02:26

> The IMPLICIT NONE statement is used to inhibit a very old feature of Fortran that by default treats all variables that start with the letters i, j, k, l, m and n as integers and all other variables as real arguments. Implicit None should always be used. It prevents potential confusion in variable types, and makes detection of typographic errors easier.

Mr. Shiny and New 安宇

Then tomorrow you are editing your code and you add a blah to the global scope.

The next time you use your function, instead of referring to a local variable, it refers to a global one.

tchrist

Or a teststring to the global scope.

You now have to know everything about everything that hasn't happened yet.

Cerberus

> if a function parameter or local variable with the same name is declared, it takes precedence over the global variable.

Mr. Shiny and New 安宇

Also, the day after tomorrow you edit your code and refer to the variable blsh

You didn't notice the typo but the interpreter just blithely allocates a new variable.

The write to blah never happens because it was written to blsh

tchrist

weepin beebee jeebitz

And this is one of the reasons I refuse to touch python.

Much worse than the white space thing.

There is no strict mode.

I prefer for the compiler to tell me about screwups like that.

Cerberus

02:29

@Mr.ShinyandNew安宇 Well, the code fails either way, then, doesn't it?

tchrist

Hope it isn't a life-support control on a spacecraft.

If we fail, we fall. —Gandalf

Mr. Shiny and New 安宇

@Cerberus but if you were required to declare variables, then the bugs I mentioned wouldn't have happened.

Cerberus

At any rate, I don't get how having to declare variables would solve the problem of inadvertently using the same variable name for two things that should be different. You have a problem either way, don't you?

tchrist

No, you don't.

Because they remain different then.

Cerberus

Why?

tchrist

02:31

Because you declared their scope.

Mr. Shiny and New 安宇

In the case where a function variable got turned to a global, that wouldn't happen because the variable declaration in the function would create a new variable that obscures the first one. In the second case you'd get an error at compile time (or run time) about an undeclared variable

tchrist

int x = 10;
if (rand() > 0.5) {
    int x = 20;
    print(x);
}
print(x);

Those are two completely different variables.

Mr. Shiny and New 安宇

@Cerberus In some languages it would be a compiler error. In most languages it just means that in the function you can't see the global x because there is a local x.

Cerberus

I'm not sure I understand that.

Mr. Shiny and New 安宇

Actually I'm not sure if there are languages where you can't create a local x that hides a global x.

tchrist

02:33

The if block is free to use variables of whatever name it pleases, and cannot be broken if somebody later adds another variable of the same name above or below it.

Mr. Shiny and New 安宇

@Cerberus when looking for a variable, the compiler looks in the current scope, then the parent, then the parent, and so on.

it takes the first one it finds.

tchrist

@Mr.ShinyandNew安宇 javascript's scope is broken

Cerberus

@tchrist And they would be different too in Autohotkey, apparently.

Mr. Shiny and New 安宇

@Cerberus They are not different in AHK

Cerberus

I thought the second x was local?

tchrist

02:34

I'm not sure what "local" means here. :)

It is visible only within its block.

Cerberus

Or maybe an if block doesn't have local things in Autohotkey. I don't know.

tchrist

I used an if block because it was easier to type.

Mr. Shiny and New 安宇

can you do this in AHK:
x = 10
function p() {
print(x);
}

tchrist

I could have used a function as well.

Cerberus

@Mr.ShinyandNew安宇 Yes: if there is no overlap, the function will see the global.

Mr. Shiny and New 安宇

02:36

@Cerberus right.

So let's say you have a function:

function p() {
    x = 2
    print(x)
}

Cerberus

says it

Mr. Shiny and New 安宇

and then later on, someone adds an x to the global scope with a value of "Cerberus"

then calls p()

Cerberus

Ohh.

tchrist

Now some clown comes by and ruins your life.

Cerberus

I like being inside a variable.

But I see the problem.

Mr. Shiny and New 安宇

02:37

You're a value, not a variable

The variable is x

tchrist

This is true.

He's an rvalue not an lvalue.

The problem is that the clown could show up a lot later than you think.

Cerberus

So but a similar problem would happen if someone added an x to the global scope twice, wouldn't it?

Mr. Shiny and New 安宇

So if variable declaration is required, p() must declare a new name called x. Later, when someone modifies the global scope to add an x, it doesn't hurt p() because p() already defines its own x. p() can't see the global x but that's fine.

tchrist

What compiler would not complain if it were at the same scope?

Mr. Shiny and New 安宇

@Cerberus yes, and similarly, requiring declaration prevents that.

@tchrist AHK or python or javascript in non-strict mode won't complain, because there is no declaration to complain about.

tchrist

02:40

@Mr.ShinyandNew安宇 I hate pos code.

Cerberus

@Mr.ShinyandNew安宇 But it's not fine if p can't see the global x, if the person who added the global x somehow counted on p's seeing x?

tchrist

The crucial thing here is that knowledge is limited by scope, and therefore you are safe.

Cerberus

So how does declaration work, and how does it prevent people from using the same name for different variables by accident?

tchrist

You can write a function that is completely safe.

Cerberus

I wouldn't even know how to declare a variable.

tchrist

02:41

A duplicate declaration is usually a compiler error, if it is at the same scope.

Cerberus

But I have some work to do before bed, and it's already 4.40.

tchrist

Well, you need a keyword to declare it.

I have to go too.

Cerberus

@tchrist Hmm I see.

Mr. Shiny and New 安宇

@Cerberus No, if a person adds a new variable "x" to a global scope, they should logically expect that nobody uses it, and anyone they want to use it needs to be modified.

tchrist

int x;
float num;
char *crap[32];

Cerberus

02:43

@Mr.ShinyandNew安宇 Hmm.

By modified you mean notified?

Mr. Shiny and New 安宇

@Cerberus No. I mean, if I take one of your scripts, and add a variable called cat, why should I expect that any function in your script uses that variable?

tchrist

This is why Mrs Clinton wants every student to take some programming class(es) before college.

Mr. Shiny and New 安宇

I have to inspect that script and modify every function that I intend to use my cat

Cerberus

@Mr.ShinyandNew安宇 Yes, I understood that.

@Mr.ShinyandNew安宇 Ah OK.

Then "anyone" is a typo?

Mr. Shiny and New 安宇

@Cerberus I meant it as "any function"

sorry, personification, it's a thing programmers do

Cerberus

02:45

Ahh OK.

I think I see the advantage.

But I also see a disadvantage: it requires much more coding, doesn't ?

If you forget to declare the function, or if you delete the declaration by accident, or if the code that is supposed to declare it isn't executed for some reason, you have a problem.

tchrist

Not really.

Because if declarations are mandatory, if you delete the declaration, you no longer have a program.

That is, the compiler will reject it.

Cerberus

Oh, I see.

So much depends on the compiler...

Mr. Shiny and New 安宇

@Cerberus normally it's not an issue because you are used to doing it. and its benefits outweigh the costs.

tchrist

That's its job.

Cerberus

But what if the declaration is there, but it isn't executed when it should?

tchrist

02:49

I don't understand.

Actually, strike that.

Mr. Shiny and New 安宇

I don't want to type := in assignment, but I do want the compiler to force me to type var in front of variable declarations in Javascript.

Cerberus

E.g. you call a variable before it is declared.

tchrist

You don't understand that declarations are not executable statements.

Mr. Shiny and New 安宇

@Cerberus That's not legal.

Cerberus

@Mr.ShinyandNew安宇 Yes, so you'd have a problem, no?

tchrist

02:50

Therefore, there is no possibility that it would not be executed. Or would be. It cannot execute.

Mr. Shiny and New 安宇

@Cerberus well, yes, the same as if you didn't put in the declaration, because it's the same error.

tchrist

You cannot use a variable before it is declared. That's why you have to declare it. The compiler is a stern mistress.

Cerberus

But would the compiler know?

tchrist

Oh yes.

The compiler knows everything. :)

Mr. Shiny and New 安宇

I wonder if there are compilers that hoist variable declarations that allow using before declaring....

tchrist

02:52

I prefer not to wonder about that. :/

Cerberus

But the declaration might be in a function at the top of the script, and I might call it in another function at the bottom. And I have marked the variable as global in both scripts because I will want to use it later again.

How would the compiler know?

Mr. Shiny and New 安宇

@tchrist ah, yes, Typescript does that

tchrist

@Cerberus I don't follow, sorry.

Cerberus

I'd love to have such a smart compiler.

Mr. Shiny and New 安宇

5

Q: Why does typescript allow variable to be used before declaring it?

Typescript does not give a compiler error for the following code: var b = a + 10; // Why no compilation error here var a = 10; alert(b.toString()); I would expect the first line to be an error as I have not declared or initialized var a till this time. If I remove the second line I get the ...

tchrist

02:53

In C, variables are int by default, but we will hate you.

Plus eventually the linker will have its way with you if it's in the global namespace.

Mr. Shiny and New 安宇

@Cerberus The declaration has to be in the scope it's in.

tchrist

Ok, I think I may see what he's getting at.

There is declaration versus initialization.

Cerberus

> Function1() { I hereby declare global variable x }
Function2() { I hereby call upon global variable x}
I execute thee, function 2()
I multiply thee by three, o global variable x

tchrist

Declaration is a compile-time thing, initialization a run-time thing, and it is possible to declare, then use, then init, and be in trouble.

Mr. Shiny and New 安宇

@Cerberus In most languages that I know of you can't declare a global variable anywhere but in the global namespace.

tchrist

02:56

You are conflating declaration with initialization.

Declaring a variable makes it visible, but initializing it gives it a value.

SmokeDetector

[ SmokeDetector ] Manually reported answer (batch report: post 1 out of 2): Where to buy cheap NFL jerseys? by wyadmin on english.stackexchange.com …

tchrist

Visibility is different.

Oh fine.

Cerberus

@Mr.ShinyandNew安宇 But that can be useful. I can do that in Autohotkey. I'd hate to have to work around that?

SmokeDetector

[ SmokeDetector ] Manually reported question (batch report: post 2 out of 2): Where to buy cheap NFL jerseys? by lrhwy on english.stackexchange.com …

tchrist

DO THE RIGHT THING

Mr. Shiny and New 安宇

02:57

@Cerberus It can be useful, but there are ways to make that possible without throwing out variable declaration

You just have a global object where you can add stuff.

tchrist

Spam flag both, all ye lurkers in the murk.

Cerberus

@SmokeDetector Flagged.

@Mr.ShinyandNew安宇 Sounds more complicated...

tchrist

It's another of those spam seeds et semini ejus.

Cerberus

Dative?

tchrist

@Cerberus Well, if you explain what you really want, we can tell you how it is normally used.

@Cerberus By their seeds? :)

Mr. Shiny and New 安宇

02:58

@Cerberus Nah it's simple.

in the global scope you define a map (or "associative array")

in functions you can read/write whatever you want in it

Cerberus

@tchrist By would be an ablative. Dative is for indirect objects only, to/for.

And semini is dative singular.

tchrist

@Cerberus The quote was promised something to your seeds.

Yes, to.

It was just a flash memory.

Cerberus

@Mr.ShinyandNew安宇 I wouldn't know how to do that. And, even if I did, it would require a lot of code.

Transcript for

English Language & Usage: Multi-Layer…