- Fail if no parameter is provided.
- The "CALL :label args..." syntax is available only when command extensions
are enabled. Fail if this syntax is used outside of a batch context.
- Reparse the CALL command parameter with the command parser, in order
to accurately parse and interpret it as a possible command (including
escape carets, etc...) and not duplicate the logic.
** CURRENT Windows' CMD-compatibility LIMITATION ** (may be lifted in
a "ROS-specific" running mode of CMD): only allow standard commands to
be specified as parameter of the CALL command.
This reparsing behaviour can be observed in Windows' CMD, by dumping
the interpreted commands after enabling the cmd!fDumpParse flag from
a debugger (using public symbols).
- When reparsing, we should tell the parser to NOT ignore lines that
start with a colon, because in this situation these are to be
considered as valid "commands" (for parsing "CALL :label").
* For Windows' CMD-compatibility, the remaining escape carets need to
be doubled again so that, after the new parser step, they are escaped
back to their original form. But then we also need to do it the "buggy"
way à la Windows, where carets in quotes are doubled either! However
when being re-parsed, since they are in quotes they remain doubled!!
(see "Phase 6" in https://stackoverflow.com/a/4095133/13530036 ).
* A MSCMD_CALL_QUIRKS define allows to disable this buggy behaviour,
and instead tell the parser to not not interpret the escape carets.
- When initializing a new batch context when the "CALL :label" syntax is
used, ensure that we reuse the same batch file position pointer as its
parent, so as to have correct call label ordering behaviour.
That is,
:label
ECHO hi
CALL :label
:label
ECHO bye
should display:
hi
bye
bye
i.e., the CALL calls the second label instead of the first one (and
thus entering into an infinite loop).
Finally, the "CALL :label" syntax strips the first ':' away, so, as a
side-effect, the command "CALL :EOF" fails (otherwise it would perform
a "GOTO :EOF" and succeeds), while "CALL ::EOF" succeeds.
Fixes some cmd_winetests.
All these modifications have been verified with Windows' CMD, either
by using written cmd_rostests and the existing cmd_winetests, or
manually by enabling the flags cmd!fDumpTokens and cmd!fDumpParse
(available in the public symbols) and analyzing how the tokens are
being parsed, as well as the generated command tree.
See also the following links for more details (but remember that these
observations have to be double-checked in Windows' CMD!):
* Parser rules: https://stackoverflow.com/a/4095133/13530036
* Discussion: https://www.dostips.com/forum/viewtopic.php?f=3&t=8355
* Numbers parsing: https://www.dostips.com/forum/viewtopic.php?t=3758
* Label names vs. GOTO and CALL: https://www.dostips.com/forum/viewtopic.php?f=3&t=3803
and: https://www.dostips.com/forum/viewtopic.php?f=3&t=3803&p=55405#p55405
- Fix REM command parsing. A C_COMMAND-like structure should still
be built, so that it can show up during batch command echo. However
some specific handling needs to be done, so use instead a new C_REM
command type.
Escape carets are parsed differently than usual: they are explicitly
kept in the command line and don't participate in line continuations.
Also, the Windows' CMD behaviour is to discards everything before the
last line continuation.
- Prefix operator '@' (the "silent" operator) is parsed as a separate
command. Thus, the command @@foo@bar is parsed as: '@', '@', 'foo@bar'.
- Improve the checks for numbered redirection.
For this purpose, we check whether this is a number, that is in first
position in the current parsing buffer or is preceded by a whitespace-
like separator, including standard command operators (excepting '@' !)
and double-quotes.
- Empty command blocks, i.e. "( )", standing by themselves, or present
in IF or FOR commands, are considered invalid. (The closing parenthesis
is considered "unexpected".)
- Ignore single closing parenthesis when being outside of command blocks,
thus interpreting it as a command, and ignore explicitly everything
following on the same line, including line continuations.
This very specific situation can happen e.g. while running in batch mode,
when jumping to a label present inside a command block.
See the code for a thorough explanation.
- Detect whether a parenthesized block is not terminated at the end
of a command stream (getting a NUL character instead of a newline),
and if so, bail out early instead of entering into an infinite loop.
- Perform a similar check for the parenthesized list in FOR commands.
- Initialize the static 'InsideBlock' value to a known value.
- The '&' operator (multi-commmand) is allowed to have an empty RHS.
When such situation occurs, turn the CurrentTokenType to TOK_END
so as to avoid a parse error later on.
- The main body of a IF statement, or its 'else' clause, as well as
the main body of a FOR statement, must not be empty, otherwise this
is considered a syntax error. If so, call ParseError() that sets
the 'bParseError' flag, and forcing all batch execution to stop.
This functionality is: case insensitivity comparisons (/I);
CMDEXTVERSION and DEFINED unary operators; EQU, NEQ, LSS, LEQ, GTR, GEQ
generic string comparators.
We note two things, when CMD searches for the corresponding label in the
batch file:
- the first character of the line is always ignored, unless it's a colon;
- the escape caret ^ is supported and interpreted.
Fixes some cmd_winetests.
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.
- Use a common large string buffer for temporary command substitutions/expansions,
instead of having such a buffer in the local stack of the parsing and
echoing functions that may be called recursively. Since CMD executes
synchronously we know that this common buffer can only be used once at
a time.
- Also do a small code cleanup in ParseIf(), ParseFor() and ParseCommandPart().
Add a MSCMD_ECHO_COMMAND_COMPAT define to be able to switch back to our
older but less broken behaviour at compile-time.
- Append a trailing space to commands when those have a parameter,
as well as after a command-block closing parenthesis.
- Space around redirection strings need to be switched around.
- Use ConOutPuts() instead of ConOutPrintf() for displaying strings that
are not printf formatted.
- When echo-ing/unparsing FOR command, any possible FOR variables
present in the FOR parenthesized list (before the "do" part) should be
substituted as well.
