parsing template?

[Alan Mead]

I filed a bug because CLUSTER hangs on unknown subcommands.  It turns
out that (for reasons I don't fully understand) the main parsing loop
never terminates when an unsupported or invalid subcommand is used.  I
don't understand how the parsing works with all the lex_*() functions. 
It looks like when any unexpected subcommand is present that the rest of
the command is ignored and the "lex_token (lexer) != T_ENDCMD" condition
is never met.

Is there a working template of how parsing is supposed to occur?

I can fix the issue by adding a final else at the end of parser:

$ diff quick-cluster.c quick-cluster.c.original
579,584d578
<       else
<         {
<         lex_error (lexer, _("Invalid or unsupported subcommand"));
<         goto error;
<       }
<

Is there a reason not to do this? One reason is that it will break any
SPSS syntax that uses unsupported subcommands but that seems better than
having PSPP hang.

-Alan

-- 

Alan D. Mead, Ph.D.
President, Talent Algorithms Inc.

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