The true use of 'constant'?

[tooltiperror]

Why should I make a function constant? What will it do?

 

[Nestharus]

From my guide-

Constant functions may not call non-constant functions and they may not manipulate any element that cannot be a constant (arrays and code).

Both regular functions and constant functions are inlined if they follow these rules:
* The function is a one-liner

* If the function is called by call the function's contents must begin with a variable assignment (=) or a function call or be a return of a single function.

* If the inlined function is an assigment, it should not assign one of its arguments (input).

* Every argument must be evaluated once and only once by the function, in the same order as they appear in the arguments list.

* If the function contains function calls, they should all be evaluated after the arguments UNLESS the function is marked as non-state changing, at the moment some very few native functions and also return bug exploiters are considered as non-state changing.

So really, constant functions are pretty deprecated.

Constants that aren't inlined are exactly the same speed as their non-constant cousins

 

[Weep]

From my guide-

So, which parts apply to vanilla JASS? (If you hadn't noticed, ToolTipError is on a Mac and doesn't care to use vJASS.)

Constants that aren't inlined are exactly the same speed as their non-constant cousins

AFAIK, there's no inlining with the stock WE compiler, so does that mean there is no difference made by declaring a constant function?

 

[weaaddar]

The constant keyword is meant to imply something about usage, but because the constant natives are terrible and stateful, it doesn't really mean anything.

 

[Nestharus]

Precisely, and there's absolutely no speed difference between constant functions and regular functions with plain old JASS.

->Constants that aren't inlined are exactly the same speed as their non-constant cousins

 

[Jesus4Lyf]

If you write a constant function, it should tell the user that running that function over something does not change the state of anything. IE, getting a widget's life does not change that widget's life or edit any variables, it has no "side effects".

So constant functions only return values, calculated or not.

 

[weaaddar]

Except that some constant natives have side effects or inconsistent returns. ergo its useless.

 

[Jesus4Lyf]

If you write a constant function, it should

Doesn't stop me from explaining the theory.

 

[Anachron]

I never used constant functions.

Also there is one word, static, that does something like constant with if constructs.

static if LIBRARY_TABLE then
    call BJDebugMsg("You have the library table in the map.")
endif

This will print the text if you have a library called table. The static part means its checked for parsing. If you don't have the library, it gets commented out.