From 3b69b121def33bb02d01ba23a7148129ab2aed46 Mon Sep 17 00:00:00 2001 From: Daniel Shahaf Date: Fri, 29 Jan 2016 09:18:34 +0000 Subject: 37831: typeset: Document exit status difference from parameter assignment statements --- Doc/Zsh/builtins.yo | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'Doc') diff --git a/Doc/Zsh/builtins.yo b/Doc/Zsh/builtins.yo index fb630a713..cdf405b13 100644 --- a/Doc/Zsh/builtins.yo +++ b/Doc/Zsh/builtins.yo @@ -1826,6 +1826,23 @@ reserved word interface for tt(typeset) may cause problems with the output of `tt(typeset -p)', which assumes the reserved word interface is available in order to restore array and associative array values. +Unlike parameter assignment statements, tt(typeset)'s exit status on an +assignment that involves a command substitution does not reflect the exit +status of the command substitution. Therefore, to test for an error in +a command substitution, separate the declaration of the parameter from its +initialization: + +example(# WRONG +typeset var1=$(exit 1) || echo "Trouble with var1" + +# RIGHT +typeset var1 && var1=$(exit 1) || echo "Trouble with var1" +) + +To initialize a parameter var(param) to a command output and mark it readonly, +use tt(typeset -r )var(param) or tt(readonly )var(param) after the parameter +assignment statement. + If the shell option tt(TYPESET_SILENT) is not set, for each remaining var(name) that refers to a parameter that is already set, the name and value of the parameter are printed in the form of an assignment. -- cgit 1.4.1