Re: [rules-users] DSL Entry Question
On 27 May 2011 16:24, jstroup <jstroup(a)regenstrief.org> wrote:
Hi,
The 5.2 docs list the following example DSL entry
[when][][Tt]here is an? {entity:\w+}=${entity!lc}: ${entity!ucfirst} ()
Oops, there is a spurious '$', the second one. It should be
=${entity!lc}: {entity!ucfirst} ()
and say the following about what follows the equals sign
"The remaining part of the line after the delimiting equal sign is the
replacement text for any DSLR text matching the regular expression. It may
contain variable references, i.e., a variable name enclosed in braces."
What does the colon following the first variable do?
The colon in "...=${entity!lc}: {entity!ucfirst} ()" will remain a colon,
after expansion. It's the colon after a binding variable.
Also, I'm used to (and actually understand) the following syntax
which does
not prefix { with a $.
[when]There is some {cheese} cheese available=Cheese(type=="{cheese}")
My best guess is that the $ denotes a class name that is specified
declaratively in the matching DSLR rule as opposed to a field {cheese} that
is simply a replaceable parameter that matches whatever you type between
"some" and "cheese available" and looks for Cheese objects of that
type.
So,
given the first DSL entry, if my rule text is
when
there is a cheese
the rule will fire if a Cheese object has been inserted. And, conversely
when
There is an Cheese
will also fire.
Since both expand to
$cheese: Cheese ()
Am I on the right track here?
yes, and thanks for the Q.
-W
Thanks,
Jeff
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