catch returns the value of the last statement, so instead of the (str) you
could just return 0.0.
Also don't use read-string if you only expect floating point numbers,
otherwise (convert-to-float ":hmm") returns :hmm, not exactly a float.
Since closure uses Double as the default floating point
You could wrap the catch expression in a do block and return something at
the end of the block.
That means that the other statements in the do block must produce some side
effect, like logging the error message:
(defn convert-to-float [a]
(try
(if (not= a " ")
(read-string a))
(ca
