reload - Reloading Clojure Code/Routes - Issue with using the symbol vs. var -

i'm new clojure, , trying few simple web routes set up. want routes reload associated code in development, not in production.

i able work using var's routes, not actual symbols. can explain if i'm doing wrong? if not, why var required?

(def app-handler   (let [formats [:json-kw :edn :yaml-kw :yaml-in-html :transit-json :transit-msgpack]         wrapped-api (wrap-restful-format #'routes/api-routes :formats formats)         combined-routes (compojure.core/routes wrapped-api #'routes/html-routes)         with-defaults (wrap-defaults combined-routes api-defaults)]     (if (is-dev?)       ; development       (wrap-reload with-defaults)       ; production       with-defaults))) 

(note #'routes/api-routes , #'routes/html-routes above).

in manner described in more detail in answer, server ends capturing route functions when passed in, , if provide var, ensure server uses updated definitions.

this considered normal way provide route or handler function during development, can see updated definitions without having restart web server process.