Add CreateDir and List for directory manipulation

2 files changed, 17 insertions, 4 deletions

diff --git a/docs/spec/system.html b/docs/spec/system.html
index d8a1e26d..5181867e 100644
--- a/docs/spec/system.html
+++ b/docs/spec/system.html
@@ -155,7 +155,7 @@
 </table>
 <p>Times are Unix timestamps, that is, seconds since the Unix epoch, as used by <a href="#time">time</a> system values.</p>
 <h3 id="file-access">File access</h3>
-<p>File access functions read or write files, either by manipulating files as a whole or interacting with the contents. Whole-file functions cannot overwrite target files: that is, <code><span class='Function'>Rename</span></code> and <code><span class='Function'>Copy</span></code> must give an error if a file exists at <code><span class='Value'>𝕨</span></code>, while <code><span class='Function'>Chars</span></code>, <code><span class='Function'>Lines</span></code>, and <code><span class='Function'>Bytes</span></code> can overwrite the contents of an existing file <code><span class='Value'>𝕨</span></code>. However, these three functions must give an error if <code><span class='Value'>𝕨</span></code> exists and is a directory.</p>
+<p>File access functions read or write files, either by manipulating files as a whole or interacting with the contents. Whole-file functions cannot overwrite target files: that is, <code><span class='Function'>Rename</span></code> and <code><span class='Function'>Copy</span></code> must give an error if a file exists at <code><span class='Value'>𝕨</span></code>, and <code><span class='Function'>CreateDir</span></code> if a file exists at <code><span class='Value'>𝕩</span></code>, while <code><span class='Function'>Chars</span></code>, <code><span class='Function'>Lines</span></code>, and <code><span class='Function'>Bytes</span></code> can overwrite the contents of an existing file <code><span class='Value'>𝕨</span></code>. However, these three functions must give an error if <code><span class='Value'>𝕨</span></code> exists and is a directory.</p>
 <table>
 <thead>
 <tr>
@@ -177,6 +177,10 @@
 <td>Copy file <code><span class='Value'>𝕩</span></code> to path <code><span class='Value'>𝕨</span></code></td>
 </tr>
 <tr>
+<td><code><span class='Function'>CreateDir</span></code></td>
+<td>Create a directory at path <code><span class='Value'>𝕩</span></code></td>
+</tr>
+<tr>
 <td><code><span class='Function'>Remove</span></code></td>
 <td>Delete file <code><span class='Value'>𝕩</span></code></td>
 </tr>
@@ -185,6 +189,10 @@
 <td>Recursively delete directory <code><span class='Value'>𝕩</span></code> and all contents</td>
 </tr>
 <tr>
+<td><code><span class='Function'>List</span></code></td>
+<td>Return names of all files in directory <code><span class='Value'>𝕩</span></code></td>
+</tr>
+<tr>
 <td><code><span class='Function'>Chars</span></code></td>
 <td>Read from or write to entire file, as characters</td>
 </tr>
@@ -198,7 +206,8 @@
 </tr>
 </tbody>
 </table>
-<p><code><span class='Function'>Rename</span></code> and <code><span class='Function'>Copy</span></code> return the path of the new file. <code><span class='Function'>Remove</span></code> and <code><span class='Function'>RemoveDir</span></code> return <code><span class='Number'>1</span></code> to indicate successful removal (and error otherwise).</p>
+<p><code><span class='Function'>Rename</span></code>, <code><span class='Function'>Copy</span></code>, and <code><span class='Function'>CreateDir</span></code> return the path of the new file. <code><span class='Function'>Remove</span></code> and <code><span class='Function'>RemoveDir</span></code> return <code><span class='Number'>1</span></code> to indicate successful removal (and error otherwise).</p>
+<p><code><span class='Function'>List</span></code> returns filenames only, without extensions. It lists all files and directories including hidden ones, but not the current and parent directory names <code><span class='Value'>.</span></code> and <code><span class='Value'>..</span></code>.</p>
 <p>Functions <code><span class='Function'>Chars</span></code>, <code><span class='Function'>Lines</span></code>, and <code><span class='Function'>Bytes</span></code> are all ambivalent. If only <code><span class='Value'>𝕩</span></code> is given, then it is a filename, and the result is the contents of the file in the appropriate format. If there are two arguments, then <code><span class='Value'>𝕨</span></code> is the filename and <code><span class='Value'>𝕩</span></code> is the desired contents. These are written to the file, overwriting its contents, and the absolute filename <code><span class='Value'>𝕨</span></code> is returned. The three formats are:</p>
 <ul>
 <li>Chars: BQN characters, or UTF-32. The file is assumed to be UTF-8 encoded.</li>
diff --git a/spec/system.md b/spec/system.md
index 67989d31..06722d76 100644
--- a/spec/system.md
+++ b/spec/system.md
@@ -80,20 +80,24 @@ Times are Unix timestamps, that is, seconds since the Unix epoch, as used by [ti
 
 ### File access
 
-File access functions read or write files, either by manipulating files as a whole or interacting with the contents. Whole-file functions cannot overwrite target files: that is, `Rename` and `Copy` must give an error if a file exists at `𝕨`, while `Chars`, `Lines`, and `Bytes` can overwrite the contents of an existing file `𝕨`. However, these three functions must give an error if `𝕨` exists and is a directory.
+File access functions read or write files, either by manipulating files as a whole or interacting with the contents. Whole-file functions cannot overwrite target files: that is, `Rename` and `Copy` must give an error if a file exists at `𝕨`, and `CreateDir` if a file exists at `𝕩`, while `Chars`, `Lines`, and `Bytes` can overwrite the contents of an existing file `𝕨`. However, these three functions must give an error if `𝕨` exists and is a directory.
 
 | Name        | Summary
 |-------------|--------------------------
 | `Open`      | Return an open file object based on `𝕩`
 | `Rename`    | Rename file `𝕩` with path `𝕨`
 | `Copy`      | Copy file `𝕩` to path `𝕨`
+| `CreateDir` | Create a directory at path `𝕩`
 | `Remove`    | Delete file `𝕩`
 | `RemoveDir` | Recursively delete directory `𝕩` and all contents
+| `List`      | Return names of all files in directory `𝕩`
 | `Chars`     | Read from or write to entire file, as characters
 | `Lines`     | Read from or write to entire file, as lines
 | `Bytes`     | Read from or write to entire file, as bytes
 
-`Rename` and `Copy` return the path of the new file. `Remove` and `RemoveDir` return `1` to indicate successful removal (and error otherwise).
+`Rename`, `Copy`, and `CreateDir` return the path of the new file. `Remove` and `RemoveDir` return `1` to indicate successful removal (and error otherwise).
+
+`List` returns filenames only, without extensions. It lists all files and directories including hidden ones, but not the current and parent directory names `.` and `..`.
 
 Functions `Chars`, `Lines`, and `Bytes` are all ambivalent. If only `𝕩` is given, then it is a filename, and the result is the contents of the file in the appropriate format. If there are two arguments, then `𝕨` is the filename and `𝕩` is the desired contents. These are written to the file, overwriting its contents, and the absolute filename `𝕨` is returned. The three formats are: