From the TASM manual:
"NEAR labels defined with the colon directive (:) are considered block-scoped
if they are located inside a procedure, and you've selected a language
interfacing convention with the MODEL statement. However, these symbols are
not truly block-scoped; they can't be defined as anything other than a near
label elsewhere in the program."
MASM's own local label syntax - declaring labels using @@ and then jumping to
the next and previous @@ using @F and @B - is obviously too limiting for any
longer function, and is not even supported by TASM unless we switch it to MASM
mode completely.
While this is indeed ugly, it only affected 16 files, which is way less than
what we would get in a TASM build without LOCALS. In comparison to having a
modern, cross-platform assembler, that really is a small price to pay.
Really, Borland? You considered it necessary to add directives for object-
oriented programming (in Assembly!) and convenience features like bitfield
records or PUSHSTATE/POPSTATE, yet you never came up with the actually
*helpful* idea of just adding a simple basic pointer data type that depends
on the current memory model's data size?
Like, something like DP... oh wait, that's already taken, as an alias for
DF, the 48-bit 80386 far pointer type.
And this, exactly, is the problem with assemblers. The language itself is
undefined beyond the instructions themselves, but it's obviously very
uncomfortable to program anything with just that, so your assembler needs to
add custom directives on top of that, and of course everyone has different
ideas of the features and use cases that should (and should not) be covered by
syntax. (I'm looking especially at you, NASM.)
And then one of those developers sells their compiler division to a different
company, which then subsequently discontinues all products without ever
releasing the source code, trapping their nice extensions in a single
executable for a single platform that is not even legally available anymore.
tl;dr: http://xkcd.com/927/
Once you've actually found the right syntax that makes the assembler just use
the default call type of the current memory model for both procedures (where
it's just "PROC" without anything else) and labels (where it's "LABEL PROC"),
these constants become completely unneccessary, even with TASM.
nmlgc