>> kazinator The let special form is a syntactic sugar for IIFEs which has the advantage of highlighting local variables ; so the previous area2 function can b

>> kazinator The let special form is a syntactic sugar for IIFEs which has the advantage of highlighting local variables ; so the previous area2 function can be rewritten this way: {def area3 {lambda {:a :b :c} {let { {:a :a} // in fact, it's a hidden lambda {:b :b} // we must redefine the outer lambda's arguments {:c :c} // as kind of "manual" closure {:s {/ {+ :a :b :c} 2}} // and add the new computed variable } {sqrt {* :s {- :s :a} {- :s :b} {- :s :c}}} everything is known }}}