progn Special Form, Up:
Now that we have seen how
we can see how the
zap-to-char function works as a whole.
The first argument to
kill-region is the position of the cursor
zap-to-char command is given—the value of point at
that time. Within the
progn, the search function then moves
point to just after the zapped-to-character and
point returns the
value of this location. The
kill-region function puts together
these two values of point, the first one as the beginning of the region
and the second one as the end of the region, and removes the region.
progn special form is necessary because the
kill-region command takes two arguments; and it would fail if
point expressions were written in
sequence as two additional arguments. The
progn expression is
a single argument to
kill-region and returns the one value that
kill-region needs for its second argument.