More file IO!

Can now create, delete, and write to files.

doc/site/modules/io/file-flags.markdown

@@ -0,0 +1,48 @@
+^title FileFlags Class
+
+Contains constants for the various file flags used to open or create a file.
+These correspond directly to the flags that can be passed to the POSIX
+[`open()`][open] syscall.
+
+[open]: http://linux.die.net/man/2/open
+
+They are integers and can be bitwise or'ed together to produce a composite
+flag.
+
+## Static Methods
+
+### FileFlags.**readOnly**
+
+The file can be read from but not written. Equivalent to `O_RDONLY`.
+
+### FileFlags.**writeOnly**
+
+The file can be written but not read from. Equivalent to `O_WRONLY`.
+
+### FileFlags.**readWrite**
+
+The file can be both read from and written to. Equivalent to `O_RDWR`.
+
+### FileFlags.**sync**
+
+Writes will block until the data has been physically written to the underling
+hardware. This does *not* affect whether or the file API is synchronous. File
+operations are always asynchronous in Wren and may allow other scheduled fibers
+to run.
+
+This is a lower-level flag that ensures that when a write completes, it has
+been flushed all the way to disc.
+
+### FileFlags.**create**
+
+Creates a new file if a file at the given path does not already exist.
+
+### FileFlags.**truncate**
+
+If the file already exists and can be written to, its previous contents are
+discarded.
+
+### FileFlags.**exclusive**
+
+Ensures that a new file must be created. If a file already exists at the given
+path, this flag will cause the operation to fail.

doc/site/modules/io/file.markdown

@@ -10,10 +10,25 @@ a file descriptor.
 
 ## Static Methods
 
+### File.**create**(path, fn)
+
+Opens the file at `path` for writing and passes it to `fn`. If there is already
+a file at that path, it is truncated. After the function returns, the file is
+automatically closed.
+
+    :::wren
+    File.create("numbers.txt") {|file|
+      file.writeBytes("one two three")
+    }
+
+### File.**delete**(path)
+
+Deletes the file at `path`.
+
 ### File.**open**(path, fn)
 
-Opens the file at `path` and passes it to `fn`. After the function returns, the
-file is automatically closed.
+Opens the file at `path` for reading and passes it to `fn`. After the function
+returns, the file is automatically closed.
 
     :::wren
     File.open("words.txt") {|file|
@@ -37,9 +52,20 @@ Returns the size in bytes of the contents of the file at `path`.
 
 ## Constructors
 
+### File.**create**(path)
+
+Opens the file at `path` for writing. If there is already a file at that path,
+it is truncated.
+
+    :::wren
+    var file = File.create("colors.txt")
+    file.writeBytes("chartreuse lime teal")
+    file.close()
+
 ### File.**open**(path)
 
-Opens the file at `path` for reading.
+Opens the file at `path` for reading. You are responsible for closing it when
+done with it.
 
 ## Methods
 
@@ -79,3 +105,13 @@ the file.
     File.open("example.txt") {|file|
       System.print(file.readBytes(6, 2)) //> am a f
     }
+
+### **writeBytes**(bytes)
+
+Writes the raw bytes of the string `bytes` to the end of the file.
+
+### **writeBytes**(bytes, offset)
+
+Writes the raw bytes of the string `bytes` to the to the file, starting at
+`offset`. Any overlapping bytes already in the file at the offset are
+overwritten.

doc/site/modules/io/template.html

@@ -29,6 +29,7 @@
       <ul>
         <li><a href="directory.html">Directory</a></li>
         <li><a href="file.html">File</a></li>
+        <li><a href="file-flags.html">FileFlags</a></li>
         <li><a href="stat.html">Stat</a></li>
         <li><a href="stdin.html">Stdin</a></li>
       </ul>
@@ -48,6 +49,7 @@
           <ul>
             <li><a href="directory.html">Directory</a></li>
             <li><a href="file.html">File</a></li>
+            <li><a href="file-flags.html">FileFlags</a></li>
           </ul>
         </td>
         <td>