Clojure

some-> behaves differently than -> when used with macros

Details

  • Type: Defect Defect
  • Status: Closed Closed
  • Priority: Minor Minor
  • Resolution: Declined
  • Affects Version/s: Release 1.5
  • Fix Version/s: None
  • Component/s: None
  • Labels:
    None

Description

I stumbled across a behavior of some-> when used with macros, and I'm wondering whether it's expected.

I started with something like this:

(some-> value
foo
bar
quux)

Then I realized that quux might throw an exception, which I want to ignore, so had the possibly misguided idea to do this:

(defmacro catch->nil [& body]
`(try ~@body (catch Exception _# nil)))

(some-> value
foo
bar
quux
catch->nil)

My mental model of some-> is that it should end up wrapping the whole expression in a try-catch, as > does, but that does not happen. some> expands into a `let` instead of a deeply-nested form, so the exception is not caught.

Certainly easy to work around, now that I know about it, but I thought perhaps this was not intended.

Activity

Alex Miller made changes -
Field Original Value New Value
Resolution Declined [ 2 ]
Status Open [ 1 ] Closed [ 6 ]

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Dates

  • Created:
    Updated:
    Resolved: