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From: "S. Cowles" <scowles@earthlink.net>
Reply-To: scowles@earthlink.net
Organization: personal
To: zsh users <zsh-users@sunsite.dk>
Subject: help with dereferencing variables
Date: Sat, 14 Feb 2004 09:59:20 -0800
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In the following code, method 1 gives the expected results.  Method 2,=20
however, breaks with the error:  unknown file attribute.  Is the eval in=20
Method 1 required, or is there a correct syntax to make the dereference occ=
ur=20
in Method 2 without an eval?

(This is a code fragment of a routine that will assign array values to=20
parameters.)

Thanks, scowles at earthlink dot net

#!/bin/zsh
# variable 1 initialize.
m1=3D
# variable 1 values.
m2=3D"
	/ld1
	/ld2
"
# variable 2 initialize.
m3=3D
# variable 2 values.
m4=3D"
	/pk1
	/pk2
"
# correspondence matrix
cm=3D"
	m1 m2
	m3 m4
"
rows=3D${#${(f)cm}}
for (( row =3D 1 ; $row <=3D $rows ; row++ ))
do
	key=3D${${=3D${${(f)cm}[${row}]}}[1]}
	val=3D${${=3D${${(f)cm}[${row}]}}[2]}
	# method 1:
	b=3D$(echo "${key}=3D( ${(@)${(P)val}} )")
	eval $b
	echo "	>${key}<:  ${(P)${key}}"
	# method 2:
	${key}=3D( ${(@)${(P)${val}}} )
	echo "	>${key}<:  ${(P)${key}}"
done
exit 0