From ad2bd42c858aa7236e7b7404806d16b5b0efb6ac Mon Sep 17 00:00:00 2001 From: Peter Stephenson Date: Fri, 23 Sep 2005 17:03:16 +0000 Subject: 21758: optimise =(<<<...) to run within the shell. --- Doc/Zsh/expn.yo | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Doc') diff --git a/Doc/Zsh/expn.yo b/Doc/Zsh/expn.yo index a75513b25..60c74cab1 100644 --- a/Doc/Zsh/expn.yo +++ b/Doc/Zsh/expn.yo @@ -340,6 +340,15 @@ process. This may be used instead of the tt(<) form for a program that expects to lseek (see manref(lseek)(2)) on the input file. +There is an optimisation for substitutions of the form +tt(=LPAR()<<<)var(arg)tt(RPAR()), where var(arg) is a single-word argument +to the here-string redirection tt(<<<). This form produces a file name +containing the value of var(arg) after any substitutions have been +performed. This is handled entirely within the current shell. This is +effectively the reverse of the special form tt($LPAR()<)var(arg)tt(RPAR()) +which treats var(arg) as a file name and replaces it with the file's +contents. + The tt(=) form is useful as both the tt(/dev/fd) and the named pipe implementation of tt(