Here is a brief summary of some of the topics covered in this chapter.
Evaluate each argument in sequence, and return the value of the first
argument that is not
nil; if none return a value that is not
nil. In brief, return the first true value
of the arguments; return a true value if one or any of the
others are true.
Evaluate each argument in sequence, and if any are
nil; if none are
nil, return the value of the last
argument. In brief, return a true value only if all the arguments are
true; return a true value if one and each of the others is
A keyword used to indicate that an argument to a function definition is optional; this means that the function can be evaluated without the argument, if desired.
Convert the raw prefix argument produced by
"P") to a numeric value.
Move point forward to the beginning of the next line, or if the argument
is greater than one, forward that many lines. If it can’t move as far
forward as it is supposed to,
forward-line goes forward as far as
it can and then returns a count of the number of additional lines it was
supposed to move but couldn’t.
Delete the entire contents of the current buffer.
t if its argument is a buffer; otherwise return