Clojurescript 如何使用数字关键字读取字符串映射？

Question

尝试从字符串读取 HashMap ，但如果键是“关键字”类型值，我从 cljs.reader/read-string 收到错误。从字符串中读取 HashMap 的正确方法是什么？

这个没有关键字的版本可以工作:

(cljs.reader/read-string (pr-str {1 "a", 1481876814936 "sdafa", 1481876816039 "afdas", 1481876817344 "asdfa", 2 "b"}))
=> {1 "a", 1481876814936 "sdafa", 1481876816039 "afdas", 1481876817344 "asdfa", 2 "b"}

但是这个带关键字的版本会报错:

(cljs.reader/read-string (pr-str {:1 "a", :1481876814936 "sdafa", :1481876816039 "afdas", :1481876817344 "asdfa", :2 "b"}))
 cljs.user=> #object[TypeError TypeError: Cannot read property '0' of null]
TypeError: Cannot read property '0' of null
    at cljs$reader$read_keyword (file:///test/resources/public/js/ui-out/cljs/reader.js:681:19)
    at cljs$reader$read_delimited_list (file:///test/resources/public/js/ui-out/cljs/reader.js:397:20)
    at cljs$reader$read_map (file:///test/resources/public/js/ui-out/cljs/reader.js:466:41)
    at cljs$reader$read (file:///test/resources/public/js/ui-out/cljs/reader.js:879:34)
    at cljs$reader$read_string (file:///test/resources/public/js/ui-out/cljs/reader.js:911:25)
    at eval (eval at figwheel$client$utils$eval_helper (file:///test/resources/public/js/ui-out/figwheel/client/utils.js:143:8), <anonymous>:1:114)
    at eval (eval at figwheel$client$utils$eval_helper (file:///test/resources/public/js/ui-out/figwheel/client/utils.js:143:8), <anonymous>:9:3)
    at eval (eval at figwheel$client$utils$eval_helper (file:///test/resources/public/js/ui-out/figwheel/client/utils.js:143:8), <anonymous>:14:4)
    at figwheel$client$utils$eval_helper (file:///test/resources/public/js/ui-out/figwheel/client/utils.js:143:8)
nil

同样的代码适用于 clojure:

user=> (read-string (pr-str {:1 "a", :1481876814936 "sdafa", :1481876816039 "afdas", :1481876817344 "asdfa", :2 "b"}))
{:1 "a", :1481876814936 "sdafa", :1481876816039 "afdas", :1481876817344 "asdfa", :2 "b"}

Answer 1

cljs.reader 不支持以数字字符开头的关键字，可能是因为符号以及扩展的关键字必须以非数字字符开头，尽管官方文档中的公式对多种解释持开放态度。见 http://clojure.org/reference/reader#_symbols和 http://clojure.org/reference/reader#_literals

clojure 阅读器(jvm 实现)总是支持像 :1234 这样的关键字，而且现在可能不会改变。

更短的失败示例:

(require 'cljs.reader)
(cljs.reader/read-string ":1")

附录:使用 keyword 函数在 clojure 中构造其他类型的不可读关键字始终是可能的，使用这些关键字导致的问题属于“未定义的行为” - 换句话说:你是如果您执行 (keyword "")

之类的操作，请自行决定

附录 1:关于 cljs.reader 中问题的 JIRA 票证位于 http://dev.clojure.org/jira/browse/CLJS-677