Light Table appears to collapse multiple consecutive spaces.
Expected behavior: (str "hello " "there") => "hello there"
Actual behavior: (str "hello " "there") => "hello there"
I assume this is "just" a display issue related to light table's HTML-based platform. You can confirm this by evaluating these expressions:
(= "hello there" (str "hello " "there")) ; true
(= "hello there" (str "hello " "there")) ; false