CODEWITHSUNDEEP
compiler-constructionclojurefunctional-programmingqualified-name
Dominik G
Dominik G

Reputation: 1479

./ in Clojure (qualified symbol?)

I'm currently implementing a different language (Shen) in Clojure.

Shen has a symbol "./" but in Clojure this is interpreted before evaluation and thus results in an error. I do not need "./" inside the macro which is compiling this function to Clojure code.

Is there a way to ignore this? I think it is interpreted as an qualified symbol but without a name, since replacing it by a/ or xyz/ results in the same error messages.

My current macro is as simple as

(defmacro kl/trap-error [x [y z r]] `(try ~x (catch Exception '~z ~r)))

But when I call it with Shen code the following happens:

kl=> (trap-error (/ 1 0) (./ E (error-to-string E)
RuntimeException Invalid token: ./  clojure.lang.Util.runtimeException (Util.java:156)
CompilerException java.lang.RuntimeException: Unable to resolve symbol: E in this context, compiling:(NO_SOURCE_PATH:0)
CompilerException java.lang.RuntimeException: Unable to resolve symbol: E in this context, compiling:(NO_SOURCE_PATH:89)

I hope someone can help me with this.

Thanks in advance.

Upvotes: 2

Views: 394

Answers (1)

amalloy
amalloy

Reputation: 91917

This is not possible without modifying the Clojure reader (a privilege which is not given to Clojure programmers). Your statement "Shen has a symbol ./ but in Clojure this is interpreted before evaluation and thus results in an error" is incorrect, though - no interpretation or evaluation goes on at all, because the reader sees these characters and can't even figure out what data type they should be.

  • Are they a list? Nope, no parens.
  • Are they a string? Nope, no quotes.
  • Are they a symbol? Nope, there would be a namespace but no name.
  • ...many more cases like this...
  • I give up, this isn't a data structure that represents valid Clojure code.

Upvotes: 2

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