#t if the argument is an input port (or a combined input
and output port), and returns
lookahead-u8 procedure (if input-port is a binary port)
lookahead-char procedure (if input-port is a textual port)
the end-of-file object, and
The operation may block indefinitely if no data is available
but the port cannot be determined to be at end of file.
maybe-transcoder must be either a transcoder or
open-file-input-port procedure returns an
input port for the named file. The file-options and
maybe-transcoder arguments are optional.
The file-options argument, which may determine
various aspects of the returned port (see R6RS File Options),
defaults to the value of
The buffer-mode argument, if supplied,
must be one of the symbols that name a buffer mode.
The buffer-mode argument defaults to
If maybe-transcoder is a transcoder, it becomes the transcoder associated with the returned port.
If maybe-transcoder is
#f or absent,
the port will be a binary port and will support the
Otherwise the port will be a textual port, and whether it supports
is implementation-dependent (and possibly transcoder-dependent).
Returns a fresh binary input port connected to standard input. Whether
the port supports the
operations is implementation-dependent.
This returns a default textual port for input. Normally, this default
port is associated with standard input, but can be dynamically
re-assigned using the
with-input-from-file procedure from the
io simple (6) library (see rnrs io simple). The port may or
may not have an associated transcoder; if it does, the transcoder is