《通链参考手册》


Function READ-LINE

●语法设定:

read-line &optional input-stream eof-error-p eof-value recursive-p

=> line, missing-newline-p

●参数和值:

input-stream---an input stream designator. The default is standard input.

eof-error-p---a generalized boolean. The default is true.

eof-value---an object. The default is nil.

recursive-p---a generalized boolean. The default is false.

line---a string or the eof-value.

missing-newline-p---a generalized boolean.

●详情:

Reads from input-stream a line of text that is terminated by a newline or end of file.

If recursive-p is true, this call is expected to be embedded in a higher-level call to read or a similar function used by the Lisp reader.

The primary value, line, is the line that is read, represented as a string (without the trailing newline, if any). If eof-error-p is false and the end of file for input-stream is reached before any characters are read, eof-value is returned as the line.

The secondary value, missing-newline-p, is a generalized boolean that is false if the line was terminated by a newline, or true if the line was terminated by the end of file for input-stream (or if the line is the eof-value).

●例子:

 (setq a "line 1
 line2")
=>  "line 1
 line2"
 (read-line (setq input-stream (make-string-input-stream a)))
=>  "line 1", false
 (read-line input-stream)
=>  "line2", true
 (read-line input-stream nil nil)
=>  NIL, true

●副作用: None.

●受制于:

*standard-input*, *terminal-io*.

●例外情况:

If an end of file[2] occurs before any characters are read in the line, an error is signaled if eof-error-p is true.

●更多信息:

read

●说明:

The corresponding output function is write-line.


X3J13设计清单非标准部分,可查下面章节:


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