expr with leading zero

[Joachim Winkler]

Hi folks !

Yesterday I got a little problem with the expr function. If I use
operands with leading zero, the interpreter (tcl7.4) returns a syntax
error or the return value is indefinite. This happens only with some
special operands.

Example:

% expr 06 + 3
9

% expr 09 + 5
syntax error in expression "09 + 5"

% expr 012 * 3
30

Why does this happen ??

thnx,
Joachim

--
*********************************************************************
* Joachim Winkler < win...@gkn.de> priv.: 74080 Heilbronn *
* GKN, Abt. LRP I, 74382 Neckarwestheim *
*********************************************************************

[JeroenHoppenbrouwers]

Joachim Winkler (win...@gkn.de) wrote:
> % expr 09 + 5
> syntax error in expression "09 + 5"

> Why does this happen ??

According to the Tcl documentation, numbers starting with a zero are
assumed to be OCTAL. '9' is no allowed octal character.

Numbers starting with '0x' are considered hexadecimal.

--
Jeroen Hoppenbrouwers, Senior Researcher at | Stop connecting computers;
Infolab, Tilburg University, The Netherlands | start connecting people!
http://infolabwww.kub.nl:2080/infolab/people/hoppie

[Peter Booth]

Joachim Winkler <win...@gkn.de> writes

> Hi folks !
>
> Yesterday I got a little problem with the expr function. If I use
> operands with leading zero, the interpreter (tcl7.4) returns a syntax
> error or the return value is indefinite. This happens only with some
> special operands.
>
> Example:
>
> % expr 06 + 3
> 9
>

> % expr 09 + 5
> syntax error in expression "09 + 5"

The leading zero is used to indicate octal encoding. You get an error for
09 because 9 is not a valid octal digit

Peter Booth