Re:That's because.. (Score 1)

Weakly typed means variables have no type to speak or, or they are every type.

This is one definition of "weakly typed" that I hear a lot. Except most folks tack on the fact values *do* have types (otherwise, you're looking at assembly where everything has type bit string or brainf*ck or forth or what have you). The other definition, which I believe is apt, is that the language provides many implicit conversions.

In PHP "5" and 5 are the same thing, there is no difference between them as far as the language is concerned. It is a string and an int, that's the very nature of a weakly typed language. That is what makes them "easy" all conversions are automagic.

That means in PHP you can do "5" + 5 and the answer should be "10" and 10. It is impossible to know when I give you "5" + 5 + "5" in PHP whether I meant concat or add or some combination.

Here is the difficulty. I think you are conflating two different ideas:

a) Variables do not have types, but values do.
b) "Lots of" implicit conversions exist in the language*.

For example, "5" and 5 definitely *are* different as far as the language is concerned. To convince yourself of this, try evaluating is_string(5) and is_int("5"). You can easily be convinced that is_string(5) will always output FALSE, and is_string("5") will always output TRUE. Thus values must have types associated with them. However, the output of is_string($foo) depends on the value of $foo (not the variable).

With that said, it is correct that PHP will make "easy conversions" "automagically". But this illustrates that PHP definitely is converting a value of some type A to a value of some different type B. And most importantly, PHP knows if a value has some type A or B.

Okay, now that my pendantic ramblings are out of the way, this is significant because under the hood, PHP can detect if $foo or "5" or whatever is a string. Thus it can make the result of $foo + $bar + $baz be a concatenation if any of $foo, $bar, or $baz are strings, and it can make it an addition if none are strings (or it can add until it finds a string, or whatever).

This can happen because PHP is a typed language, and it doesn't particularly matter if PHP was dynamically typed, statically typed, "weakly typed", "strongly typed", "duck typed" or whatever.

So anyways, it *is* possible to use + as both a concatenation and addition operator in a meaningful way. However, to use it the way I have suggested would break existing code. Furthermore, since I haven't really followed PHP development for a while, I can't say if the community would even welcome such a change (if no code needed to be updated).

* Exactly how many implicit conversions the language must offer to you before you call it weakly typed I do not know. Java offers some implicit conversions, but people call it strongly typed. Ruby offers a lot, but not as many as PHP, and so people argue about whether or not it is weakly typed. Scala offers programmer defined implicit conversions, so I do not even know what to think about weak typing in that case, which is why the term means so little to me.