File Module

(file/close f)

Close a file and release all related resources. When you are done reading a file, close it to prevent a resource leak and let other processes read the file.

(file/flush f)

Flush any buffered bytes to the file system. In most files, writes are buffered for efficiency reasons. Returns the file handle.

(file/lines file)

Return an iterator over the lines of a file.

(file/open path &opt mode buffer-size)

Open a file. path is an absolute or relative path, and mode is a set of flags indicating the mode to open the file in. mode is a keyword where each character represents a flag. If the file cannot be opened, returns nil, otherwise returns the new file handle. Mode flags:

• r - allow reading from the file

• w - allow writing to the file

• a - append to the file

Following one of the initial flags, 0 or more of the following flags can be appended:

• b - open the file in binary mode (rather than text mode)

• + - append to the file instead of overwriting it

• n - error if the file cannot be opened instead of returning nil

See fopen (<stdio.h>, C99) for further details.

(file/read f what &opt buf)

Read a number of bytes from a file f into a buffer. A buffer buf can be provided as an optional third argument, otherwise a new buffer is created. what can either be an integer or a keyword. Returns the buffer with file contents. Values for what:

• :all - read the whole file

• :line - read up to and including the next newline character

• n (integer) - read up to n bytes from the file

(file/seek f &opt whence n)

Jump to a relative location in the file f. whence must be one of:

• :cur - jump relative to the current file location

• :set - jump relative to the beginning of the file

• :end - jump relative to the end of the file

By default, whence is :cur. Optionally a value n may be passed for the relative number of bytes to seek in the file. n may be a real number to handle large files of more than 4GB. Returns the file handle.

(file/tell f)

Get the current value of the file position for file f.

(file/temp)

Open an anonymous temporary file that is removed on close. Raises an error on failure.

(file/write f bytes)

Writes to a file. 'bytes' must be string, buffer, or symbol. Returns the file.