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(import-macros {: fn*} :macros.fn)
(local _unpack (or table.unpack unpack))
(fn check-bindings [bindings]
(assert-compile (sequence? bindings) "expected binding table
* Try placing a table here in square brackets containing identifiers to bind." bindings)
(assert-compile (= (length bindings) 2) "expected exactly two forms in binding vector." bindings))
(fn* if-let
([bindings then]
(if-let bindings then 'nil))
([bindings then else]
(check-bindings bindings)
(let [[form test] bindings]
`(let [tmp# ,test]
(if tmp#
(let [,form tmp#]
,then)
,else)))))
(fn* when-let
[bindings & body]
(check-bindings bindings)
(let [[form test] bindings]
`(let [tmp# ,test]
(if tmp#
(let [,form tmp#]
,(_unpack body))))))
(fn* if-some
([bindings then]
(if-some bindings then 'nil))
([bindings then else]
(check-bindings bindings)
(let [[form test] bindings]
`(let [tmp# ,test]
(if (= tmp# nil)
,else
(let [,form tmp#]
,then))))))
(fn* when-some
[bindings & body]
(check-bindings bindings)
(let [[form test] bindings]
`(let [tmp# ,test]
(if (= tmp# nil)
nil
(let [,form tmp#]
,(_unpack body))))))
{: if-let
: when-let
: if-some
: when-some}
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