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mksh-current has just gained an experimental recursive parser for command substitutions, fixing RedHat BZ#496791 and decades-old complaints about the pdksh codebase, compared to AT&T ksh93. (GNU bash could also do the example, but not some other things mksh(1) parses fine now.)

This means that things like the following work now.

	# POSIX, should “always” work
	echo $(case 1 in (1) echo yes;; (2) echo no;; esac)
	# POSIX optional, works now in mksh, works in GNU bash
	echo $(case 1 in 1) echo yes;; 2) echo no;; esac)
	# GNU bash seems to choke on comments ending with backslash
	# a comment with " ' \
	x=$(
	echo yes
	# a comment with " ' \
	)
	# No non-recursive COMSUB parser can pass all of the above
	# tests and these below at the same time (some extensions)
	echo $(typeset -i10 x=16#20; echo $x)
	echo $(typeset -Uui16 x=16#$(id -u)
	) .
	echo $(c=1; d=1
	typeset -Uui16 a=36#foo; c=2
	typeset -Uui16 b=36 #foo; d=2
	echo $a $b $c $d)
	# the ‘#’ is especially tricky, that’s why the above cases
 

Next on my TODO is the complete rewrite of the read built-in command, as well as its documentation. I think that the (reduced) goals for mksh R40 will have been met by then, except porting to LynxOS and MPE, but we’re working on it, and re-testing Syllable and Plan 9). Of course, a release implies testing on a lot of the supposedly supported platforms, so it won’t be out “immediately”. Though, associative arrays have been removed from the R40 goals, so that I can at least get a new release out. Note that Debian and OpenSuSE Buildservice users have been provided with somewhat well-tested mksh-current snapshots for a while already, and Gentoo users can use the “live ebuild”; there’s always compiling from source too…

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