Automatically add "$" character into PHP scripts

Question

I have a programming text editor (written in PHP) and want to remove the $ signs available in PHP scripts upon loading of the document for editing ... to "quietly" insert them back once the user saves the file. Basically, I want to save the user the work of always typing the $ icon in front of variables (similar to how you don't have to in, say, Python).

My question: With which PHP code could I insert the $ signs back into the script?

Even if the functionality would make some compromises and assumptions in terms of coding style -- i.e. not work in edge cases -- I think it would be very useful.

Edit: As I originally mentioned, I'm OK with compromises in terms of style. Here's an example syntax that might be easin' the parsin' and still be nicer to write IMO:

for (var i = 1; i <= 10; i++) { /* look ma, no $s! */ }

Answer 1

It's not possible, because it would make the syntax ambiguous. You couldn't tell the difference between a variable and a defined constant, for example.

Answer 2

This would be down to your IDE wouldn't it? You could have a script to run it through which will put the $'s back once you are done editing. Just depends on what your IDE is capable of.

I can't really see it being much of a problem, is it that hard to add one character?

Answer 3

I suggest you not to add this "feature". People who are acquainted with PHP will habitually type in the '$' sign, voiding the need for this. Additionally, as Lukas said, the $ sign has a reason to be there...

Answer 4

It doesn't sound like a good idea.

As has been mentioned, the syntax will become ambiguous.

You don't say so, but your text editor is presumably NOT doing syntax highlighting, even though you are putting code in it.

Removing $ signs from variable names would make syntax highlighting impossible to implement - a very valuable addition to a programming text editor.

Answer 5

It could probably be done - it is entirely possible to implement programming languages without a "$" symbol - and I not convinced the "$" symbol was implemented to remove ambiguity in the first place. (Having the special symbol in an interpreted language could be used to speed up the parsing when differentiating between what's a variable, a constant, or a function of some sort for example).

However, it would be tricky. You'd pretty much have to have a pretty deep knowledge of PHP and lookup table of some form in order to work out what is what i.e. if it's in the lookup table it's a reserved word, etc. You'd need to track anything the user does which could be mistaken for a variable - which you'd likely need to do by checking the context. IT would be a huge and complex project.

So while I think you could do it (and keep Syntax highlighting - since the information required to do that would be basically required to implement this feature) the effort required seems to far out weigh the benefit of not having to type a simple $ symbol in front of your variables.

Answer 6

I think too it is a bad idea, it might be simpler to code in Python or Lua or some other language without these $ (inherited from Perl, I think).

Beside, you would need a full PHP lexer/parser to get it nearly right, and I guess you will get lot of corner case hard to fix, like interpolation in strings.

Answer 7

There is no way you can fix:

$blah = "hello";
"blah blah blah $blah blah";

Without using an escape character. So you have to rewrite as:

$blah = "hello";
"blah blah blah " . $blah . " blah";

But that goes against the feeling of php. And that reminds me of the pascal programmer who has problem using C and found the following solution:

#define BEGIN {
#define END }

The morale of the story is to accept a language as it is. There are enough to chose from.

Answer 8

This is a crazy idea but this can be done. If you will have to tell the editor that these are the variables. To do this you will have to use var i,variable_name to let the editor know that these are variables. Or something in comments.