$@
Specify a database-map argument RHS database operator
When looking up information or performing actions with
the $( and
$) operators,
it is sometimes necessary to provide positional
substitution arguments. To illustrate, consider an
entry such as this in a hypothetical database source
file:
hostA %0!%1@%2
With such an entry in place, and having built the database, the following rule could be used to perform a lookup:
R$- @ $-.uucp $: $(uucp $2 $@ $1 $@ mailhost $: $1.$2.uucp $)
Here, if the workspace contains the address joe@hostA.uucp, the LHS matches, causing it to be rewritten as hostA!joe@mailhost.
See Specify Numbered Substitution with $@ on page 894 for a full description of how
$@ is used in
this way.
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