Question

我需要从edn文件中读取一个clojure函数，该文件输出hiccup来生成html内容。但是我被困在需要评估函数的部分。我收到错误消息：

java.lang.RuntimeException: Unable to resolve symbol: fn in this context, compiling:(null:1:1)

((eval (read-string "(fn [] (list [:div\"Hello\"]))")))

和

((load-string "(fn [] (list [:div\"Hello\"]))"))

在clojure REPL中工作并输出预期结果

([:div "Hello"])

project.clj

(defproject infocenter "0.1.0-SNAPSHOT"
  :dependencies [[org.clojure/clojure "1.8.0"]
                 [org.clojure/clojurescript "1.9.225"]
                 [hiccup "1.0.5"]]
  :plugins [[lein-figwheel "0.5.4-7"]]
  :clean-targets ^{:protect false} [:target-path "out" "resources/public/cljs"]
  :cljsbuild {
              :builds [{:id "dev"
                        :source-paths ["src"]
                        :figwheel true
                        :compiler {:main "templ.core"
                                   :asset-path "cljs/out"
                                   :output-to  "resources/public/cljs/main.js"
                                   :output-dir "resources/public/cljs/out"}}]}
  :figwheel {
             :css-dirs ["resources/public/template"]})

core.cljs

(ns templ.core
  (:require-macros [templ.edn :refer [read-edn]]))
(let [div (. js/document getElementById "content")]
     (set! (. div -innerHTML) (read-edn "fn.edn")))

edn.clj

(ns templ.edn
  (:use [hiccup core form]))

(defmacro read-edn
  "Read template from file in resources/"
  [edn-name]
  ;(slurp edn-name)
  ;((eval (read-string "(fn [] (list [:div\"Hello\"]))")))
  ((load-string "(fn [] (list [:div\"Hello\"]))"))
  )

Answer 1

试试这个：

(ns xyz.core
  (:gen-class))

(defn -main
  "I don't do a whole lot ... yet."
  [& args]
  (println "main - enter")
  (println (eval '(+ 2 3)))
  (println ((eval (read-string "(fn [] (list [:div\"Hello\"]))"))))
  (println "main - exit")
)

结果：

> lein run
main - enter
5
([:div Hello])
main - exit

这只是简单的Clojure，我看到你也在使用CLJS。使用CLJS部分进行设置时可能会出现问题。你想对read-edn和fn.edn做什么？我会尽可能完全避免使用宏。

可以从字符串中删除/加载字符串clojure函数

1 个答案: