underlying difference between elseif vs else if

Question

I was wondering the differnce between elseif and else if.

I was reading the manual which says if using the braces {} they are

Answer 1

In addition to my comment, from what I can see in the PHP source, the only speed boost is that PHP's parser has a special token for elseif, unsurprisingly known as T_ELSEIF. But I'm sure the speed boost is nothing more than a side effect of allowing elseif in the alternative syntax:

if (cond1):
    // Do something
elseif (cond2):
    // Do something else
else:
    // Do something else
endif;

Similar to Python, which uses elif, else if with a space wouldn't be allowed without having to unnecessarily complicate the parser's implementation code (i.e. to act differently between seeing a colon and the if keyword). So a colon is required directly after else and if respectively, and that's how the language rule is stipulated.

Ergo I'm pretty sure PHP just treats else if as a conditional block in a singular-statement else.

If there are any speed differences at all, blame the parser for most of them.