[_v7gu]

Isn't 100 lines too much for a simple utility like wc? I get that it has many edge cases to cover, but edge cases usually require some different handling when you run into them anyway. I'd rather use my one-liner (including calculation in a single pass, and even parallel processing!):

    wc:{sum (({1};ceiling 0.5*sum differ " "=;{1+count x})@\:) peach read0 x}