| Re: Using function prototypes in code [message #175037 is a reply to message #175036] |
Fri, 05 August 2011 03:08   |
Jerry Stuckle
Messages: 2598
Registered: September 2010
Karma:
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Senior Member |
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On 8/4/2011 8:53 PM, webber wrote:
> In the interest of clarity and maintainability I would like to be able
> to write code that makes it clear what kind of arguments a function
> expects and what it returns.
>
> This is what I tried:
>
> function integer int_func(string $s) {
> // does something like, say, converting "five" to 5
> }
>
> There are two problems:
> 1 The appearance of a type name before the function name is treated as
> a syntax error
> 2 Even if I forget about declaring the return type and code it instead
> as
>
> function int_func(string $s) {
> ...
> }
>
> I get a run-time error when I call the function with a string. (eg
> $var = int_func("five");) The error message says"Catchable fatal
> error: Argument 1 passed to int_func() must be an instance of string,
> string given".
>
> It seems that basic data types cannot be specified in ths way although
> (intstances of) classes can. I have successfully used the technique to
> catch run-time errors of wrong object types when testing, but am
> surprised that I can't use it to trap unexpected basic types - or at
> least to document what is expected.
>
> To confuse me a bit further, I can't find a definitive list of the
> basic type names. For example, is it "integer" or "int"?
You can only use objects or arrays with type hinting, not the standard
types (and "string" is not a defined class name). See
http://www.php.net/manual/en/language.oop5.typehinting.php
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex(at)attglobal(dot)net
==================
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