Comment Before Commands??

[Meerkat]

Hi again guys. Maybe someone else discovered this already.

One time while I am making a Batch game because I am bored, I used a comment like this:

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@echo off
%== Main loop: check for win and lose condition ==%

But when I executed this: This happened...

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'check' is not recognized as an internal or external command,
operable program or batch file.

So I tried to experiment:

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%=: @echo off
%=: main 2>nul
%=: for /l %%A in (1,1,10) do (
%=:    for /l %%B in (1,1,10) do (
%=:      if "%%A"=="%%B" (
%This is a good comment :         echo(%%A == %%B
%=:      )
%Hmm... Another comment here:   )
%=: )
%=: pause
%=: goto :main

And the code works as expected. The main part should have 2>nul because this is treated as both a command and a label.
I do not know why is this happening, but I expect that you know this already.

Also I expect that this does not have any applications. I tried hybridization, but % is rarely used as a comment.

Meerkat

[jeb]

Hi Meerkat,

the cause of your problem is the colon, it starts a special handler for the variable, but when the variable (in your case "== Main loop") isn't defined, then the text after the colon will be used.
Dave's compendium about variable expansion is at SO: How does the Windows Command Interpreter (CMD.EXE) parse scripts?

[Squashman]

I believe this was also discussed here in one of the Batch Macro threads.
viewtopic.php?f=3&t=5374