std-unix@longway.TIC.COM (Moderator, John S. Quarterman) (04/06/90)
From: Maarten Litmaath <uunet!cs.vu.nl!maart> In article <528@ehviea.ine.philips.nl>, leo@ehviea.ine.philips.nl (Leo de Wit) writes: )... )The fact that the terminating } has to be preceded by a command )separator as opposed to the terminating ) where it is not needed, seems )rather odd to me. This also goes for the start {, that has to be )followed by white space to be considered a token, as opposed to the )start (. Was { } perhaps a 'last minute hack' ? Whatever, it has the advantage of making the following possible: $ echo {1,2,3}{a,b,c} 1a 1b 1c 2a 2b 2c 3a 3b 3c In csh this works as demonstrated, in ksh it's a compile-time option. Regarding the POSIX sh I say: either add this feature or let braces parse like parentheses. In the latter case the only difference between them would be: a parenthesized expression evaluates in a subshell, a braced expression evaluates in the current shell (*always*, even if the input or output of the list has been redirected; in current implementations such redirections cause evaluation in a subshell). -- 1) Will 4.5BSD have wait5()? |Maarten Litmaath @ VU Amsterdam: 2) Sleep(3) should be sleep(2) again.|maart@cs.vu.nl, uunet!mcsun!botter!maart Volume-Number: Volume 19, Number 73