Suppose the following FOR-loop command, to be run from the command-line
(if using a batch file, double each percent '%' sign):
FOR %l IN ("a,b,c,d,e" "f,g,h,i,j") DO (
FOR /F "delims=, tokens=1-3*" %a IN (%l) DO @echo %a-%b-%c-%d
)
The outermost FOR-loop enumerates the two strings "a,b,c,d,e" and
"f,g,h,i,j" (placed in %l), and parse each of these in turn, splitting
them at each specified delimiter (here only one character) ',' and storing
the results in consecutive tokens %a, %b, %c, %d, with the last token %d
containing all the remaining string (non-split).
The expected result is:
a-b-c-d,e
f-g-h-i,j
However, due to the way the delimiters string specified by the "delims="
option is stored (no stack/heap duplication of the FOR-option substring,
but reading from it directly), during the first run of the innermost
FOR-loop, the option string "delims=, tokens=1-3*" was truncated to just
after the ',' due to the erroneous "delims=" parsing, so that when this
FOR-loop ran for a second time (to deal with the second string), the option
string was already erroneously truncated, without the "tokens=..." part,
so that the parsing results were not stored in the tokens and resulting in:
a-b-c-d,e
f-%b-%c-%d
instead. The solution is to save where the "delims=" string needs to be
cut, but wait until running the actual FOR-loop to terminate it (and
saving the original character too), run the FOR-loop body, and then
restore the original character where termination took place. This allows
having the FOR-loop option string valid for the next execution of the
FOR-loop.
- To this purpose use the ParseErrorEx() that correctly sets the
bParseError flag, and return the partially-parsed command so that
it gets echoed as well for diagnostics purposes (Windows-compatible).
- Any other parameters specified after (or before) the '/?' switch for
the FOR and IF commands, are considered fatal syntax errors as well,
thus we employ the ParseErrorEx() as well.
CORE-13713 CORE-13736
- In case execution of all batch contexts is stopped (by selecting "All"
at the Ctrl-C/Ctrl-Break prompt), notify as well the CheckCtrlBreak()
signal handler once there are no more batch contexts (this in effect
resets the internal 'bLeaveAll' static flag in CheckCtrlBreak).
This is an adaptation of the fix present in FreeCOM 1.5, first
described in https://gcfl.net/FreeDOS/command.com/bugs074g.html .
- Introduce a ParseErrorEx() helper that sets the 'bParseError' flag and
displays a customized syntax-error message, only for the first syntax
error encountered. Implement ParseError() around the *Ex function.
- In batch mode, echo the original pre-parsed batch file line if a parse
error has been encountered.
- When running a compound command - including IF, FOR, command blocks -,
and that control flow is modified by any CALL/GOTO/EXIT command,
detect this while running the compound command so as to stop it and go
back to the main batch execution loop, that will then set up the actual
new command to run.
- In GOTO, do not process any more parts of a compound command only when
we have found a valid label.
