Re: PHP and case-sensitivity inconsistency in PHP 6

On 27/01/14 11:05, Alain Williams wrote:

* there are a few special values that are currently case insenitive, eg: NULL, TRUE. I would suggest that they only be recognised in upper case, eg: null would be invalid. This fits with the meme of constant names being in upper case.

I'd prefer lowercase, myself, but I do think we need consistency in case for language keywords as well as identifiers. Perhaps having everything lowercase.

* transition, there must be a lot of code that has (accidental) case inconsistencies in function/variable/... names. If PHP were not a dynamic language (eg C) then this change would be caught at compile time. In PHP a case inconsistency is only found when the code is executed. Programs can contain blocks of code that are rarely executed - think: rare error recovery. Something that would help with transition is the option to force variables to be declared. If a variable is then used without being declared an error is raised. We currently have the problem as illustrated below:

     $foo = 'bar';
     echo "foo=$f00";

With case insensitivity this problem will become worse. What I propose is something like perl's 'use strict'. This causes a compilation error if a variable is used that has not been defined. This pragma applies only for the compilation module that it is in; ie it does not apply to 'include'd files and so can be done on a module by module basis. The way that I suggest that we do this is by using the existing keyword 'var'. Eg:

     var $foo = 'bar';

or

     var $foo;

If 'var' is seen in a module, then use of any variables below MUST be for variables that have been declared. OK: that is the general idea, details need working on. Note that the use of 'var' to declare variables is OPTIONAL, only use it if you want to.

I somewhat like this idea, it reminds me of ECMAScript 5's "use strict", which I find an invaluable debugging aid and use for all my JavaScript programs. Being able to have a *strictly* optional feature defined in source, not in the INI, would be wonderful. People who want a notice can have it, but myself, I'd like my program to terminate with an error message when I use a variable I haven't defined yet, if it's a strict mode source file. Adding a strict mode would allow us to change other things without breaking BC, too, though I'm not sure what at present. -- Andrea Faulds http://ajf.me/