* Bug in parameter expansion with :- ? @ 2017-01-10 15:35 ` Ronald Fischer 2017-01-10 15:43 ` Peter Stephenson 0 siblings, 1 reply; 4+ messages in thread From: Ronald Fischer @ 2017-01-10 15:35 UTC (permalink / raw) To: zsh-workers This expands correctly to a '+': ${unset_variable:-+} This however doesn't expand to a '-', but to the empty string: ${unset_variable:--} I didn't find anything in the man page which would explain this behaviour. A note aside: Bash expands in the latter case to a dash (-). My zsh version: zsh 5.1.1 (x86_64-unknown-cygwin) Ronald ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Bug in parameter expansion with :- ? 2017-01-10 15:35 ` Bug in parameter expansion with :- ? Ronald Fischer @ 2017-01-10 15:43 ` Peter Stephenson 2017-01-10 15:55 ` Ronald Fischer 0 siblings, 1 reply; 4+ messages in thread From: Peter Stephenson @ 2017-01-10 15:43 UTC (permalink / raw) To: zsh-workers On Tue, 10 Jan 2017 16:35:00 +0100 Ronald Fischer <ynnor@mm.st> wrote: > This expands correctly to a '+': > > ${unset_variable:-+} > > This however doesn't expand to a '-', but to the empty string: > > ${unset_variable:--} You may be getting into confusions with options to builtins rather than the expansion. % print -r -- ${unset_variable:--} - pws ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Bug in parameter expansion with :- ? 2017-01-10 15:43 ` Peter Stephenson @ 2017-01-10 15:55 ` Ronald Fischer 2017-01-10 18:41 ` Nikolay Aleksandrovich Pavlov (ZyX) 0 siblings, 1 reply; 4+ messages in thread From: Ronald Fischer @ 2017-01-10 15:55 UTC (permalink / raw) To: Peter Stephenson, zsh-workers On Tue, Jan 10, 2017, at 16:43, Peter Stephenson wrote: > On Tue, 10 Jan 2017 16:35:00 +0100 > Ronald Fischer <ynnor@mm.st> wrote: > > > This expands correctly to a '+': > > > > ${unset_variable:-+} > > > > This however doesn't expand to a '-', but to the empty string: > > > > ${unset_variable:--} > > You may be getting into confusions with options to builtins rather than > the expansion. > > % print -r -- ${unset_variable:--} > - Yes I do! You are right - not a bug! Ronald ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Bug in parameter expansion with :- ? 2017-01-10 15:55 ` Ronald Fischer @ 2017-01-10 18:41 ` Nikolay Aleksandrovich Pavlov (ZyX) 0 siblings, 0 replies; 4+ messages in thread From: Nikolay Aleksandrovich Pavlov (ZyX) @ 2017-01-10 18:41 UTC (permalink / raw) To: Ronald Fischer, Peter Stephenson, zsh-workers 10.01.2017, 18:56, "Ronald Fischer" <ynnor@mm.st>: > On Tue, Jan 10, 2017, at 16:43, Peter Stephenson wrote: >> On Tue, 10 Jan 2017 16:35:00 +0100 >> Ronald Fischer <ynnor@mm.st> wrote: >> >> > This expands correctly to a '+': >> > >> > ${unset_variable:-+} >> > >> > This however doesn't expand to a '-', but to the empty string: >> > >> > ${unset_variable:--} >> >> You may be getting into confusions with options to builtins rather than >> the expansion. >> >> % print -r -- ${unset_variable:--} >> - > > Yes I do! You are right - not a bug! > > Ronald For checking what argument is literally I would suggest `printf '<%s>' $arg` instead: this will show trailing spaces due to `<>` around `%s`, let you distinguish between variable accidentally becoming an array and determine which strings are in one array item exactly (`printf '<%s>' 1 2` results in `<1><2>`, harder to miss then a space). And this also does not look like you are fighting with zsh (`-r` and `--` are there to prevent some misinterpretations). ^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-01-10 15:35 ` Bug in parameter expansion with :- ? Ronald Fischer
2017-01-10 15:43 ` Peter Stephenson
2017-01-10 15:55 ` Ronald Fischer
2017-01-10 18:41 ` Nikolay Aleksandrovich Pavlov (ZyX)
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