This compatibility behaviour implements the buggy behaviour of FOR /F
token parsing that can be observed in Windows' CMD, and that is tested
by the cmd_winetests.
It can be disabled at compile time via the MSCMD_FOR_QUIRKS define.
It fixes additional cmd_winetests, in concert with commit cb2a9c31.
Explanation of the implemented buggy behaviour
==============================================
In principle, the "tokens=x,y,m-n[*]" option describes a list of token
numbers (must be between 1 and 31) that will be assigned into variables.
Theoretically this option does not cumulate: only the latest 'tokens='
specification should be taken into account.
However things are not that simple in practice. First, not all of the
"tokens=" option state is reset when more than one specification is
provided. Second, when specifying a token range, e.g. "1-5", Windows'
CMD just ignores without error ranges that are not specified in
increasing order. Thus for example, a range "5-1" is ignored without
error. Then, token numbers strictly greater than 31 are just ignored,
and if they appear in a range, the whole range is ignored.
Another bug is the following one: suppose that the 'tokens'
specification reads:
"tokens=1-5,1-30" , or: "tokens=1-5,3" ,
i.e. more than one range, that overlap partially. Then the actual total
number of variables will not be of the larger range size, but will be
the sum, instead.
Thus, in the first example, a total of 5 + 30 == 35 variables (> 31) is
allocated, while in the second example, a total of 5 + 1 == 6 variables
is allocated, even if they won't all store data !!
In the first example, only the first 30 FOR variables will be used, and
the 5 others will contain an empty string. In the second example, only
the first 5 FOR variables will be used, and the other one will be empty.
We also see that due to that, the "Variables" buffer of fixed size
cannot always be used (since it can contain at most 32 variables).
Last but not least, when more than one "tokens=" specification is
provided, for example:
"tokens=1-31 tokens=1-20"
a total number of 31 FOR variables (because 31 is the max of 31 and 20)
is allocated, **but** only 20 are actually used, and the 11 others
return an empty string.
And in the specification: "tokens=1-31,* tokens=1-20", a total of
31 + 1 + 20 = 52 variables is initialized, but only the first 20 will
be used, and no "remaining-line" token (the '*' one) is used.
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