[9fans] minor glitch with free carets

[9fans] minor glitch with free carets

[Tom]

On Jun 10, 10:04am, Elliott Hughes wrote:
> Subject: Re:  [9fans] minor glitch with free carets
> with Byron's rc:
>
> % echo while'b'
> whileb

I spoke to Rob Pike yesterday and mentioned that I thought
that free carets were the single stupidest thing in rc.
Don't use them.  Take them out of the code.  (Apparently
I always knew this.  There's a comment in the code where
this is implemented that uses the word `embarassing.')

BTW, the bug is on line 318 of /sys/src/cmd/rc/lex.c:

	if(t->type!=WORD) lastword=0;

I think that changing this to

	lastword=0;

fixes it (I don't have a plan 9 machine, so I can't test it.)
d


--
Tom Duff.  If UNIX is the great novel, Perl is the Cliff's Notes.

[9fans] minor glitch with free carets

[rob]

i'm glad you fixed this, but please pass changes to such
central services past me beforehand.  rc is not well enough
understood to be edited at will, and much depends on its
consistent behavior.

[9fans] minor glitch with free carets

[Russ]

	i just got bitten by this...

	% echo a'b'
	ab
	% echo fn
	fn
	% echo fn'b'
	fn b
	% 

A fix is to change the word: production in /sys/src/cmd/rc/syn.y from
	word:	keyword			{$1->type=WORD;}
to
	word:	keyword			{lastword=1; $1->type=WORD;}

And you'll have to add "int lastword;" to rc.h
so that lex.c's lastword is visible.

Russ

[9fans] minor glitch with free carets

[James]

> i just got bitten by this...
>
> % echo a'b'
> ab
> % echo fn
> fn
> % echo fn'b'
> fn b
> %

Interesting -- it works under the unix rc:

    #aubrey:$h
    ;  echo a'b'
    ab
    #aubrey:$h
    ; echo fn'b'
    fnb
    #aubrey:$h
    ;

[9fans] minor glitch with free carets

[Tom]

> BTW, the bug is on line 318 of /sys/src/cmd/rc/lex.c:
>
> 	if(t->type!=WORD) lastword=0;
>
> I think that changing this to
>
> 	lastword=0;
>
> fixes it (I don't have a plan 9 machine, so I can't test it.)
Bah!  This doesn't work.  (Rob tested it for me, thanks!)
There's no easy fix.  Put a note in the BUGS section.

--
Tom Duff.  If UNIX is the great novel, Perl is the Cliff's Notes.

[9fans] minor glitch with free carets

[Elliott]

with Byron's rc:

% echo while'b'
whileb

does this mean we need an extra line in BUGS section
of Byron's rc's man page?

;-)

--
"Act Swiss. Be Global." -- ABB Werbung, 1999.

[9fans] minor glitch with free carets

[rob]

Yes, this appears to happen when the word is a keyword:

% echo while'b'
while b
% echo fn'b'
fn b
%

I can't get very excited about it.  As a matter of habit,
I have learned to put the carets in.

-rob

[9fans] minor glitch with free carets

[rog]

i just got bitten by this...

% echo a'b'
ab
% echo fn
fn
% echo fn'b'
fn b
%