Class File
The File class provides a wrapper over a C FILE * struct. A File is
closed automatically when a scope exits (though not immediately). However,
it is also possible to manually close a File.
public define close
Close self if it is open, or do nothing if already closed.
For standard streams, this marks the File as closed, but does not
actually close the stream. Embedders, therefore, do not need to worry
about standard streams being altered or closed by Lily.
public define each_line(fn: Function(ByteString))
Read each line of text from self, passing it down to fn for
processing.
IOErrorifselfis not open for reading, or is closed.
public define flush
This function writes all buffered data associated with the File
provided.
IOErrorifselfis closed or not open for writing.
public static define open(path: String, mode: String): File
Attempt to open path using the mode given. mode may be one of the
following:
"r"(read only, must exist)
"w"(write only)
"a"(append, create if not exist)
"r+"(read+write, must exist)
"w+"(read+write, creates an empty file if needed)
"a+"(read+append)
IOErrorif unable to openpath, or an invalidmodeis provided.
public define print(data: A)
Attempt to write the contents of data to the file provided. data is
written with a newline at the end.
IOErrorifselfis closed or is not open for writing.
public define read(size: *Integer): ByteString
Read size bytes from self. If size is negative, then the full
contents of self are read. This stops if either size bytes are read,
or the end of self is reached.
IOErrorifselfis not open for reading, or is closed.
public define read_line: ByteString
Attempt to read a line of text from self. Currently, this function
does not have a way to signal that the end of the file has been reached.
For now, callers should check the result against B"". This will be
fixed in a future release.
IOErrorifselfis not open for reading, or is closed.
public static define read_to_string(path: String): String
Convenience method for reading a whole file into a String.
This opens the file named path, reads all content into a String,
then closes the file.
IOErrorif unable to openpath.
ValueErrorif the content read is not valid utf-8.
public define write(data: A)
Attempt to write the contents of data to the file provided.
- If
selfis closed or is not open for writing,IOErroris raised.
public static define write_to_path(path: String, data: A)
Convenience function for writing data to a file.
This opens the file named path, writes data to it, then closes the
file.
IOErrorif unable to openpath.