Hi!
----
[Per offlist request for a "typeset -m" demo and to answer the
question how to abort object creation _after_ it has been created...]
The following demo shows how to pass variables/objects via
namerefs+typeset -m (move variables) between shell functions... in
this demo the function "createfish_t" creates a function-local (=in
the functions local scope) variable of type "printfish_t" and then
validates whether the object represents a "real" fish... if "yes" it
returns the object via nameref (which stores it as a member of the
compound variable "c" of the calling "main" function) ... otherwise
the object remains in the scope of function "createfish_t" and is
destroyed when the function exists.
-- snip --
typeset -T printfish_t=(
typeset fname
function unset
{
printf '# fish %q died.\n' "${_.fname}"
}
)
function createfish_t
{
nameref ret=$1
typeset fishname="$2"
printfish_t f
f.fname="$fishname"
# return the object via nameref _only_ if it
# is a true fish
if [[ "${f.fname}" == ~(Ei)(coelacanth|trout) ]] ; then
typeset -m 'ret=f'
fi
return 0
}
function main
{
compound c
print '# creating objects...'
createfish_t c.shark 'coelacanth'
createfish_t c.horse 'horse'
createfish_t c.trout 'trout'
print '# ... objects created.'
print -v c
}
# program start.
set -o nounset
print '# calling main...'
main
print '# main done.'
-- snip --
Output should look like this (ast-ksh.2013-04-22 prints this CORRECT :-) ):
-- snip --
# calling main...
# creating objects...
# fish horse died.
# ... objects created.
(
printfish_t shark=(
fname=coelacanth
)
printfish_t trout=(
fname=trout
)
)
# fish coelacanth died.
# fish trout died.
# main done.
-- snip --
----
Bye,
Roland
--
__ . . __
(o.\ \/ /.o) [email protected]
\__\/\/__/ MPEG specialist, C&&JAVA&&Sun&&Unix programmer
/O /==\ O\ TEL +49 641 3992797
(;O/ \/ \O;)
_______________________________________________
ast-users mailing list
[email protected]
http://lists.research.att.com/mailman/listinfo/ast-users
