In Lisp, you put the "operator" first, so instead of

  2 + 3 + 4

you write

  (+ 2 3 4)

This is nice for associative operations like + or *, very very very slightly confusing for - and /

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You use the same style for comparisons, so instead of

  2 == 3 == 4

you write

  (== 2 3 4)

To support the fist "infix" syntax, you need some magic in the == operator. But the second "prefix" syntax is totally natural and you need no magic in the parser or the operator.