Only mIRC commands remove leading, trailing and multiple spaces (and even then there are a couple of exceptions). mIRC is able to handle multiple spaces fine in identifiers (including custom ones, if one uses /returnex instead of /return). For example, one can manipulate multiple spaces in a string and replace them with something else. This would not be possible if mIRC removed multiple spaces everywhere.
Variables can also store multiple/leading spaces fine - the only problem is when there is a single trailing space, in which case you can't put it in a variable. You can put two or more trailing spaces in a variable, but not a single one.
This is something that can be worked around though. A typical example is looping through a string char by char and appending each char to a variable. This will fail when parsing strings with spaces, but it can be worked around by just putting something else after the space, then removing it before using the var's value later. Compare this:
//var %s = hello world, %i = 1, %out | while $mid(%s,%i,1) != $null { var %out = %out $+ $v1 | inc %i } | echo -ag %out
(fails to preserve the space)
to this:
//var %s = hello world, %i = 1, %out | while $mid(%s,%i,1) != $null { var %out = $left(%out,-2) $+ $v1 Z | inc %i } | echo -ag $left(%out,-2)
(works)
The latter method is just appending " Z" (two chars) to the end of %out, then strips them out with $left(...,-2) before updating its value in the next iteration. It relies on the two facts I mentioned above, ie that both variables and identifiers can handle spaces in general.
