Poor word choice on my part. The intention was that machines don't need to jump through any hoops to be able to figure out what code means - it's a language designed such that it can be parsed mechanically without ambiguity. Compare this to a machine interpreting English.

I was not intending to downplay the significance of code being intended for human consumption.

But how many characters are in a typical line of English?

Traditionally,

  Anything from 45 to 75 characters is widely-regarded as a satisfactory
  length of line for a single-column page set in a serifed text face in
  a text size. The 66-character line (counting both letters and spaces)
  is widely regarded as ideal.

— Robert Bringhurst, The Elements of Typographic Style, 3rd Edition, §2.1.2

It depends on your typography.