Re: PHP and case-sensitivity inconsistency in PHP 6

On Sun, Jan 26, 2014 at 03:36:08PM -0800, Stas Malyshev wrote: > Hi! > > > So essentially, I would like to see case sensitivity at call time > > (called name must match declaration), but case insensitivity at > > declaration time (when checking whether a symbol has already been > > declared): > > What would function_exists('Foo') return when foo() is defined? > > If false, then this code: > > if (!function_exists('Foo')) { > function Foo() { ... } > } > > would not work. If true, then this code: > > if(function_exists('Foo')) { > Foo(); > } > > would not work. Both are working fine now and there's no real reason why > shouldn't they keep working. > > Additionally, making the engine case-sensitive would simplify some areas > of function/class handling. But making it inconsistently partially > case-sensitive would instead complicate it, as we now would have to make > additional checks against original name before calling. > > My opinion is if we go case-sensitive, it must be full case sensitivity, > no exceptions. +1 We need to think about: * 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. * 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. -- Alain Williams Linux/GNU Consultant - Mail systems, Web sites, Networking, Programmer, IT Lecturer. +44 (0) 787 668 0256 http://www.phcomp.co.uk/ Parliament Hill Computers Ltd. Registration Information: http://www.phcomp.co.uk/contact.php #include <std_disclaimer.h>