I'm writing the following nested function where dfsVisit uses the arrays "numCaminos" and "colores" declared in the outer function
However the kotlin compiler is giving me a "variable expected" error on the assignments in lines 31 and 34 specifically, this error doesn't show up on any of the other Array assignments within the nested dfsVisit function. I tried de-nesting the functions and passing the arrays as arguments of dfsVisit but the problem persisted on those 2 assignments specifically. Why could this be happening?
I'm running the Kotlin compiler in Manjaro Linux through the repository package
Note: Sorry for using a picture instead of a code block, the post editor was giving me some formatting issues.
Just remove !! from the left side of the assignment. It doesn't really make sense there.
Related
here is the function that worked prior to upgrading to 7.0
function set_session_vars() {
$nb_args=func_num_args();
$arg_list=func_get_args();
for($i=0;$i<$nb_args;$i++) {
global $$arg_list[$i];
$_SESSION[$arg_list[$i]] = $$arg_list[$i];
}
}
now it causer error that says:
Parse error: syntax error, unexpected '[', expecting ',' or ';' in /home/mvyc1956/public_html/members/includes/functions.php on line 322
I believe its related to non backward compatable changes to GLOBAL and the use of $$ and arrays, but my PHP is not good enough to figure it out.
Is there someone who is familiar with why this line :
global $$arg_list[$i];
which is line 322 that is being reported as the cause of the error, would be failing now, and what would you recommend I change the code to in order to have it work with PHP 7?
I did some googling and found this page but again, im not understanding what needs to be changed.
thanks
says syntax error so some of the code in the function is no longer valid, but it would take a php 7 expert to see it.
UPDATE
I removed the word GLOBAL from the above code and the app "seems" to be now working fine so I will now ask:
Does anyone know specifically, why Global was the non compatibility issue? and is my fix of simply removing it a solid one or will is there a better practice or will this removal come back to haunt me?
Backward incompatible changes:
global only accepts simple variables
Variable variables can no longer be used with the global keyword. The curly brace syntax can be used to emulate the previous behaviour if required:
// Valid in PHP 5 only.
global $$foo->bar;
// Valid in PHP 5 and 7.
global ${$foo->bar};
So in your case it should become:
global ${$arg_list[$i]};
The global keyword tells PHP to access a global variable (per launch of the script) instead of a local variable (per function). For example,
global $foo;
means that future uses of the variable $foo in that function refer to the global variable with that name, rather than a variable within the function itself.
What this is trying to do is look up a variable by arbitrary name in the global namespace. That's entirely the wrong way to do things. Instead, you should have a global array and use keys in the array. In fact, $$ is arguably a bad idea in general.
But that's neither here nor there. The problem is that the parsing rules changed in PHP 7.0 in a non-backwards-compatible way (because they're using a more traditional parser now, and thus had to make their associativity rules self-consistent).
More details here:
http://php.net/manual/en/migration70.incompatible.php#migration70.incompatible.variable-handling.indirect
To make a long story short, you need to rewrite that as:
global ${$arg_list[$i]};
and then your code will work correctly on both PHP 7 and PHP 5.
Incidentally, the function only appears to work without the global keyword. In fact, it is always getting empty values for those variables.
I'm trying to integrate CocoaLumberjack into a project that I inherited. I've seen it work fine in the past with other projects, but for some reason, I'm getting several errors in CocoaLumberjack's code. Examples include:
Suddenly I'm getting "Assigning to 'void *' from incompatible type 'const char [1]'" compile errors on struct properties when passing in a C string.
I'm getting warnings on C arrays of C strings saying "Conversion from string literal to 'char *' is depreciated.
"class" has suddenly become a keyword (the lowercase version)
Has anyone ever seen anything similar to this? The build settings on the project have definitely been changed a bit, but I'm not sure what was done.
Any chance you're accidentally compiling the code as C++/Obj-C++? The third point there with class becoming a keyword makes that sound plausible.
i have had this happen in vs, where the errors show up from newest to oldest as the compiler runs through the source code.Try to if your doing something like this always remember to trace to the first error and go from there. I have had some pretty crazy results by putting a semicolon (;) after an include statment
ie
<string>;
<vector>;
will throw a crazy set of errors if it is in the wrong place.
I have this code:
id error;
// a bunch of stuff, including using error
Finalization finalization = ^(int status) {
id error; // <--- Declaration shadows a local variable
// a bunch of stuff, using error
}
// a bunch of stuff, using error
I use GCC_WARN_SHADOW because it's what I want in every case in my code except this one. In this case, it gives me a warning that I want to suppress.
Is there a way to suppress this one shadow warning without turning off GCC_WARN_SHADOW or renaming the inner error to something else? Some way to mark that declaration of error?
I'm using clang with Xcode 4, if it matters.
First, as a matter of opinion, it's really bad karma to shadow a local variable within an inner block (its bad enough shadowing a global variable in a function). Now "error" can take two different values within a function, and until whomever is reading your code figures it out, they will bang their head quite incessantly. I have seen this issue in real life among paid professionals developing apps. I really suggest renaming the inner error variable.
Answering your question, you can use the GCC/clang compiler pragma to suppress a warning.
Today I discovered that something I had assumed about VB.NET for many years was not true (worrying!). I assumed that a variable declared within a loop had a lifetime of the iteration it was declared in, but in fact it seems it has a lifetime of the whole procedure.
For example:
For i As Integer = 0 To 1
Dim var1 As Boolean
Console.WriteLine(var1.ToString())
var1 = True
Console.WriteLine(var1.ToString())
Next
Console.ReadKey()
I had assumed an output of False, True, False, True but instead it is actually False, True, True, True.
In C# the equivalent code would not compile as you would get a compile time error of Error "Use of unassigned local variable 'var1'".
I realise there are many ways to fix this and that best practice would be to declare the variable outside of the loop and reset it at the beginning of every loop through.
I find this behaviour so counter-intuitive to me that I would like at least a compile time warning in VB.NET when/if I do this. (I could also then set this on any projects I already have and get warning that would allow me to check that my assumptions aren't causing errors).
Does anyone know how/if I can get this to generate a compile time warning in VB.NET? Am I the only one that finds this counter-intuitive?
We'll have to work on fixing your intuition because getting an error out of the compiler is not an option. It is partially implemented, you can get this warning:
error BC42104: Variable 'mumble' is used before it has been assigned a value. A null reference exception could result at runtime.
And elevate it from a warning to an error with Project + Properties, Compile tab. However, as the warning message indicates, this is only supported for reference type references, it won't budge for a variable of a value type.
Okay, intuition. If the runtime would implement your desired behavior then it would have to allocate a new variable for each iteration of the loop. Which implies that the number of local variables is bounded only by the number of iterations. This is very wasteful and a very easy trigger for StackOverflowException. The JIT compiler doesn't do this, it re-uses the variable. This happens in C# as well, minus the option of letting you not initialize the value explicitly of course.
Fwiw: I very much agree with you that this is unhelpful behavior. You'll probably find receptive ears at connect.microsoft.com, post your feature request there and the VB.NET team will see it. There has been strong backing from customers as well as within MSFT to make VB.NET and C# feature comparable. If you post a link to your feedback report then I'll be happy to vote it up.
I'm having trouble with a .NET Assembly that is com visible, and calling certain methods from VB6.
What I have found is that if the parameters are well defined types, (e.g. string), calls work fine. If they are higher level objects, it raises a runtime error '438' suggesting that the property or method is not present. I suspect that this is a question of having the correct signature on the call, but I can't see how to do this correctly.
I believe that I've done everything correct on the .NET side (ComVisible, public interfaces, etc. and even have it down to a simple enough case).
Looking at the output from the typelib viewer, I have the following:
dispinterface ISimple {
properties:
methods:
[id(0x60020000)]
void Add([in] ISimpleMember* member);
[id(0x60020001)]
ISimpleMember* Create();
};
OK. So I have 2 methods in my ISimple interface. One takes an ISimpleMember (Add), whilst the other, returns an ISimpleMember.
The corresponding code in VB looks like this:
Dim item As ISimpleMember
Dim simple As simple
Set item = New SimpleMember
item.S1 = "Hello"
item.S2 = "World"
Set simple = New simple
simple.Add (item) <---- This raised the run time error 438
Set item = simple.Create <---- This works fine, returning me an ISimpleMember
I've tried a couple of things:
1. Dim item as SimpleMember (makes no difference)
2. simple.Add(ObjPtr(item)) - Syntax error
3. simple.Add(ByRef item) - Syntax error
Basically, The run time error is the same as if I had
simple.AMethodThatIHaventWritten()
Also, If I browse References in the VB6 Environment, The Add method is well defined:
Sub Add(member As SimpleMember)
I've found the answer I believe. It was very simple:
When calling a SubRoutine, I shouldn't put the name in braces. the call should have been:
simple.add member
rather than
simple.add(member)
If I change it to a function (i.e. return a value rather than void) the braces are necessary
This seems to work
(Probably) The top 3 VB6 coding mistakes made by devs who now mainly code in C#, Javascript etc. Are:-
Placing ; at the end of lines. Its a syntax error very easily spotted and picked up the compiler.
Not placing Then on the other side of an If condition expression. Again its a syntax error.
Calling a method without retrieving a value and yet using ( ) to enclose the parameter list. With multiple parameters this is a syntax error and easily found. With only one parameter the use of ( ) is interpreted as an expression. Its the result of the ( ) expression which is passed as parameter. This causes problems when ByRef is expected by the callee.