I am working on web software where admins will be using HTML forms to
update data in a MongoDb database. I decided to use Lamina to off-load the
work to the background. There are several operations that need to happen:
updates, deletions, etc, and I thought I'd put each on a different channel.
So I tried to write a macro to generate the code needed for each of those
channels. This was my first attempt:
(defmacro establish-channel [action noun to-execute start-function-name]
(let [channel-name (symbol (str "documents-to-" action "-in-" noun
"-channel"))
additive-action-name (symbol (str "add-to-" action "-channel"))
worker-name (symbol (str action "-" noun "-worker"))]
`(def ~channel-name (channel))
`(defn ~additive-action-name [document]
(enqueue ~channel-name document))
`(defn ~worker-name []
(loop [document @(read-channel ~channel-name)]
(~to-execute document)
(recur @(read-channel ~channel-name))))
`(defn ~start-function-name []
(future (~worker-name))
(future (~worker-name))
(future (~worker-name))
(future (~worker-name))
(future (~worker-name)))))
But in the repl, when I run this, and then I do this:
user> (macroexpand-1 (establish-channel update mongo println
start-mongo-channel))
I get:
CompilerException java.lang.RuntimeException: Unable to resolve symbol:
update-mongo-worker in this context, compiling:(NO_SOURCE_PATH:1:16)
It seems to be complaining about this line:
(future (~worker-name))
But I defined that function just above that line:
`(defn ~worker-name []
So what could the problem be?
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