wren/doc/site/modules/io/file.markdown

^title File Class

Lets you work with files on the file system. An instance of this class
represents an open file with a file descriptor.

When you are done with a file object, it's a good idea to explicitly close it.
If you don't, the GC will close it when the file is no longer used and gets
finalized, but that may take a while. In the meantime, leaving it open wastes
a file descriptor.

## Static Methods

### File.**open**(path, fn)

Opens the file at `path` and passes it to `fn`. After the function returns, the
file is automatically closed.

    :::wren
    File.open("words.txt") {|file|
      file.readBytes(5)
    }

### File.**read**(path)

Reads the entire contents of the file at `path` and returns it as a string.

    :::wren
    File.read("words.txt")

The encoding or decoding is done. If the file is UTF-8, then the resulting
string will be a UTF-8 string. Otherwise, it will be a string of bytes in
whatever encoding the file uses.

### File.**size**(path)

Returns the size in bytes of the contents of the file at `path`.

## Constructors

### File.**open**(path)

Opens the file at `path` for reading.

## Methods

### **descriptor**

The numeric file descriptor used to access the file.

### **isOpen**

Whether the file is still open or has been closed.

### **size**

The size of the contents of the file in bytes.

### **close**()

Closes the file. After calling this, you can read or write from it.

### **readBytes**(count)

Reads up to `count` bytes starting from the beginning of the file.

    :::wren
    // Assume this file contains "I am a file!".
    File.open("example.txt") {|file|
      System.print(file.readBytes(6)) //> I am a
    }

### **readBytes**(count, offset)

Reads up to `count` bytes starting at `offset` bytes from the beginning of
the file.

    :::wren
    // Assume this file contains "I am a file!".
    File.open("example.txt") {|file|
      System.print(file.readBytes(6, 2)) //> am a f
    }