process substitution cannot be part of a larger argument

[McDutchie]

Unlike a command substitution, a process substitution always becomes a separate argument, even if not surrounded by whitespace. This problem is present in all ksh versions.

This breaks GNU-style long options, as reported by @ScottRochford in att#1487:

$ echo foo<(:)bar
foo /dev/fd/4 bar
$ echo $KSH_VERSION
Version AJM 93u+ 2012-08-01

This breaks things like tar ... --files-from=<( command ) because the space separates the long option from its parameter.

[ormaaj]

Sometimes with regular command words it at least parses but splits the words. I think that's this bug.

(ins)ormaaj 3 (23237) 0 ~ $ x=foo ksh -xc ': "${x}"<(:)'
+ : foo /dev/fd/3
+ :

Then there's another problem with redirects.

(cmd)ormaaj 3 (23237) 3 ~ $ ksh -c '<$(:)<(:)'
ksh: syntax error at line 1: `<(' unexpected

That can be useful when one of the subshells is used for side-effects.