Working with Rails 3.1 (rc5), and I'm noticing that any coffeescript file I include rails (or sprockets) is adding in initializing javascript at the top and bottom. In other words, a blank .js.coffee file gets outputted looking like this:
(function() {
}).call(this);
This is irritating because it screws up my javascript scope (unless I really don't know what I'm doing). I generally separate all of my javascript classes into separate files and I believe that having that function code wrapping my classes just puts them out of scope from one another. Or, atleast, I can't seem to access them as I am continually getting undefined errors.
Is there a way to override this? It seems like this file in sprockets has to do with adding this code:
https://github.com/sstephenson/sprockets/blob/master/lib/sprockets/jst_processor.rb
I understand that wrapping everything in a function might seem like an added convenience as then nothing is ran until DOM is loaded, but as far as I can tell it just messes up my scope.
Are you intending to put your objects into the global scope? I think CoffeeScript usually wraps code in anonymous functions so that it doesn't accidentally leak variables into the global scope. If there's not a way to turn it off, your best bet would probably be to specifically add anything you want to be in the global scope to the window object:
window.myGlobal = myGlobal;
It seems to be a javascript best practice these days to put code inside a function scope and be explicit about adding objects to the global scope, and it's something I usually see CoffeeScript do automatically.
You don't want to put everything into the global scope. You want a module or module like system where you can namespace things so you don't colide with other libraries. Have a read of
https://github.com/jashkenas/coffee-script/wiki/Easy-modules-with-coffeescript
Related
I have a Swift application that uses a module, and I need to call a global function that is in the application from the module, is this possible?
To perhaps explain a little better, this is a test app structure:
CallbackTestApp contains a function foo(), I would like to call it from Module1 or File, will swift allow this?
edit #1
More details have been requested on what is the background of my issue, hopefully, this will not turn out to be an XY situation.
There's a tool developed by my company that process the application source* code and in some places add function call (ignore the why etc, have to be generic here.). Those function calls are exactly to foo() which then does some magic (btw, no return value and no arguments are allowed), if the application does not use modules or if modules are excluded from the processing then all is fine (Linker does not complain that the function is not defined), if there are modules then nothing works since I did not found a way to inject foo() (yet).
*Not exactly the source code, actually the bitcode is processed, the tool get the source, use llvm toolchain to generate bitcode, do some more magic and then add the call to foo() by generating it's mangled name and adding a swiftcall
Not actually sure those additional details will help.
PSVersion: 5.1.17134.858
I haven't done a whole lot of work with Powershell's classes but here's a simple example of what I'm running into:
class xNode{
[uint64]$MyID=0
static [uint64]$ClassID=0
xNode(){
$MyID = [xNode]::ClassID++
}
[String] ToString(){return "xNode: $MyID"}
}
doesn't parse it gives the two errors:line 6 $MyID..., "Cannot assign property, use '$this.MyID'."line 9 ..$MyID", "Variable is not assigned in the method."
I'm trying to use the classes property named $MyID, and this usage appears to be in line with the example given in the help documentation get-help about_Classes, and when I copied their whole example at the end out to a file then tried to run it I was getting the same errors as well for $Head, $Body, $Title,... Of course I can force it to work by adding this.
class xNode{
[uint64]$MyID=0
static [uint64]$ClassID=0
xNode(){
$this.MyID = [xNode]::ClassID++
}
[String] ToString(){return "xNode: $($this.MyID)"}
}
However I'd rather not have to keep typing this. all over the place, is there maybe some environment setting or something I've overlooked?
(Note: to get it to work at the commandline, I also needed to remove all of the blank lines)
However I'd rather not have to keep typing this. all over the place, is there maybe some environment setting or something I've overlooked?
No, it's working as advertised, you can't reference instance properties inside the class without the $this variable reference.
Why do powershell class properties require this within their methods?
(The following is what I'd call "qualified speculation", ie. not an officially sourced explanation)
PowerShell classes are a bit tricky from an implementers point of view, because a .NET property behaves differently than, say, a parameter in a powershell scriptblock or a regular variable.
This means that when the language engine parses, analyzes and compiles the code that makes up your PowerShell Class, extra care has to be taken as to which rules and constraints apply to either.
By requiring all "instance-plumbing" to be routed through $this, this problem of observing one set of rules for class members vs everything else becomes much smaller in scope, and existing editor tools can continue to (sort of) work with very little change.
From a user perspective, requiring $this also helps prevent accidental mishaps, like overwriting instance members when creating new local variables.
I implement MyClass containing the method method() and I store the instance in $_ENV['key'] in test.php. Also in test.php the code completion works when I type $_ENV['key']->.
In test2.php I include test.php and the code completion does not work any more for $_ENV['key']->.
Does anyone know how to enable this in PhpStorm?
AFAIK type tracking for arrays works within the same file only.
You can bypass it via intermediate variable (yes, it's not a nicest solution) and small PHPDoc comment, like this:
/** #var MyClass $myVar */
$myVar = $_ENV['key'];
$myVar->
P.S.
In general, I'd suggest not using global arrays this way (or even not using global vars at all -- only very basic stuff during bootstrap, if possible). Instead (based on your code) I may suggest using some static class (as one of the alternatives) with dedicated field where you can easily give type hint (via PHPDoc) to a class field -- this way IDE will always know hat type it is. Current PHP versions (5.5 and especially 5.6) work with objects nearly as fast as with arrays, even leading in (smaller) memory consumption.
Obviously, such suggestion does not really apply if this code is not yours.
I've done some searching on this, but I cannot find info. I'm building an application inside sinatra, and using the coffeescript templating engine. By default the compiled code is wrapped as such:
(function() {
// code
}).call(this);
I'd like to remove that using the --bare flag, so different files can access classes and so forth that I'm defining. I realize that having it more contained helps against variable conflicts and so forth, but I'm working on two main pieces here. One is the business logic, and arrangement of data in class structures. The other is the view functionality using raphaeljs. I would prefer to keep these two pieces in separate files. Since the two files wrapped as such cannot access the data, it obviously won't work. However, if you can think of a better solution than using the --bare option, I'm all ears.
Bare compilation is simply a bad practice. Each file should export to the global scope only the public objects that matter to the rest of your app.
# foo.coffee
class Foo
constructor: (#abc) ->
privateVar = 123
window.Foo = Foo # export
Foo is now globally available. Now if that pattern isn't practical, maybe you should rethink your structure a bit. If you have to export too may things, you nest and namespace things better, so that more data can be exposed through fewer global variables.
I support Alex's answer, but if you absolutely must do this, I believe my answer to the same question for Rails 3.1 is applicable here as well: Put the line
Tilt::CoffeeScriptTemplate.default_bare = true
somewhere in your application.
Just installed rails 3.1 rc1 and am trying to grok the best way to manage javascript with the new asset pipeline
By default all coffeescript is compiled into a single application.js file, this is a good thing.
Each seperate coffee script file is appended to the js file and wrapped in an anonymous function which is executed via the call method
A common scenario would be to use some jquery to turn various forms into ajax forms, update UI, etc...
Many of these scripts will be specific to a controller or action, I am trying to grok the 'conventional' way to handle this,
since everything is wrapped in an anonymous function how do I only execute just
the code for a particular controller / action, by default all of the anonymous functions are being executed
I did play around with some hacks where I load the controller and action name into js variables and then in
coffeescript check those to conditionally run code, I don't like that very much
my initial thought was that each coffee file would contain a js namespace/object and I would call the specific ones from the view,
going to spike this using the default_bare = true configuration
see How can I use option "--bare" in Rails 3.1 for CoffeeScript?
EDIT
Looking around some more: this looks like it might be the correct approach - "Can't find variable" error with Rails 3.1 and Coffeescript
There are two common approaches:
Make behavior conditional on the presence of a particular element. For instance, code to run a signup sheet should be prefaced with something like
if $('#signup').length > 0
Make behavior conditional on a class on the body element. You can set the body class using ERB. This is often desirable for stylesheets as well. The code would be something like
if $('body').hasClass 'user'
gistyle is a simple gem that helps you running action-specific javascript codes.
By following its setup, you set some data attributes in your body element, representing the current controller and action names. Then it will only call that action when the corresponding view is loaded.