A generic function that returns
t if the stream is positioned at the beginning of a line.
stream-start-line-p stream => result
Note that although a value of 0 from stream-line-column also indicates the beginning of a line, there are cases where
stream-start-line-p can be meaningfully implemented and stream-line-column cannot. For example, for a window using variable-width characters the column number is not very meaningful, whereas the beginning of a line has a clear meaning.
The default method for
stream-start-line-p on class fundamental-character-output-stream uses stream-line-column. Therefore, if this is defined to return
nil, a method should be provided for either
stream-start-line-p or stream-fresh-line.
LispWorks® User Guide and Reference Manual - 01 Dec 2021 19:31:01