>     There were actually three error messages on TRS-80s with Level I
>     BASIC: WHAT, HOW, and SORRY.  If I remember correctly, WHAT
>     indicated a syntax error; HOW indicated an attempt to resize an
>     array, which was not allowed; and SORRY meant that it had run out of
>     space.

That's amazing. I'll never be able to design something so simple.

> The `ed` editor has only one error message, `?`.  In some versions, you
> could type '?` as a command and it would give you a somewhat more
> detailed message.

The bloated messages ruin the purity of ed :)

>     :) That's one more than in R7RS, which has just file-error? and
>     read-error?

We should make a little Scheme implementation some time for laughs that
only has one-word error messages. That also calls to mind Steele's
Growing a Language lecture. Perhaps the Scheme could have compound
conditions where each simple condition is one English word.