Generating a symbol from a string and applying it as a function

Question

I\'m just learning clojure, and I\'m hitting a wall.

I\'m trying to read an arithmetic expression as an infix string and process it in Clojure.

e.g. \"1 + 2\" ->

Answer 1

Symbols have a function attached to them by default. The function that is attached to them by default is look this key up in a map. That is why your plus behaves oddly. It is attempting to look up elements in a map.

(plus 1 1) This is really look the symbol + up in the map 1 and if not found return a default value of 1.

(plus 1 2) Same as above except default value is 2.

clojure docs for symbols