add a tagging system to the website

content/programming/vfs.tree

@@ -1,4 +1,6 @@
-%% title = "composable virtual file systems"
+%% id = "b?01JDJJSEWASRWJGKMBNYMFD9B5"
+title = "composable virtual file systems"
+tags = ["programming", "treehouse"]
 
 % id = "01JDJGVC7BRZDSYTZCH0S357B8"
 - you know what I hate?
@@ -92,7 +94,7 @@ like... you know. a _virtual_ file system?
 
         % id = "01JDJGVC7BPEW2NAT7XSB5F97E"
         - first of all, from the perspective of the program, do we _really_ need to differentiate between directories and files?
-        
+
             % id = "01JDJGVC7BHQWZDS17DY0096F6"
             - from a GUI design standpoint, they're a useful abstraction for us humans---the more concrete an object, the easier it is to grasp.
             _files_ and _folders_ seem a lot more easy to grasp than abstract _entries_ which _may_ represent documents, folders, or both.
@@ -201,7 +203,7 @@ like... you know. a _virtual_ file system?
     % id = "01JDJGVC7BQZAY4TP1WG5N6QR3"
     - having a design in mind, I thought it would be interesting to integrate it into a real project.
     the treehouse seemed like the right thing to test it out on, since it's effectively a compiler---it transforms a set of source directories into a target directory.
-    
+
         % id = "01JDJH59SN5219QPGJPZS7FMA6"
         - and I have to say: so far, I'm liking it!
 
@@ -339,23 +341,23 @@ like... you know. a _virtual_ file system?
     `Edit`s take many shapes and forms, but the most important one for us is `Write`: it allows you to write a file to the disk.
 
     the other ones are for composing `Edit`s together into larger ones.
-            
+
         % id = "01JDJGVC7BCT46CXXVKMXATAA3"
         - `Seq` can be used to implement transactions, where all edits have to succeed for the parent edit to be considered successful.
 
             % id = "01JDJHDZ8XWEZAA94AW1VS4P53"
             - I use this for writing backups.
             if writing a backup fails, we wouldn't want to overwrite the original file, because we wouldn't be able to restore it!
-        
+
         % id = "01JDJGVC7B05H6079QHXAXC8Y4"
         - `All` can be used to aggregate independent edits together and execute them in parallel.
-        
+
         % id = "01JDJGVC7BKXXJSWYTGX7XA979"
         - `Dry` can be used to implement a `--dry-run` command, only printing an edit instead of applying it.
 
         % id = "01JDJGVC7B7MNC3CA5DEP1HXM6"
         + `NoOp` can be used when you need to produce an `Edit`, but don't actually want to perform any operations.
-        
+
             % id = "01JDJGVC7BJRSMS1E4NQRVZ1H2"
             - this runs contrary to [my opinion on `None` enums][branch:01HCG7KTGGAFS07QYJXZG6WHJJ], for one reason: would you rather have to handle `Option<Edit>` everywhere, or just assume whatever `Edit` you're being passed is valid?
 
@@ -373,7 +375,7 @@ like... you know. a _virtual_ file system?
 
         % id = "01JDJGVC7BGJQXTVZ6Z9BK12BG"
         - of course then you cannot create directories.
-        
+
         % id = "01JDJGVC7B2JTWKJVEE1VP6P68"
         - also, [TOCTOU](https://en.wikipedia.org/wiki/Time-of-check_to_time-of-use) bugs are a thing, but I disregard those as they don't really fit into a compiler's threat model.
 
@@ -389,7 +391,7 @@ like... you know. a _virtual_ file system?
 
         % id = "01JDJGVC7BCG0W3SWSYR647ZCC"
         - `TreehouseDir` is a file system which renders `.tree` files into HTML lazily.
-        
+
             % id = "01JDJGVC7BBJCR1TQCBKBHMBNS"
             - since generating all this HTML is an expensive operation, I have it wrapped in a `ContentCache` adapter, which caches any successfully generated pages in memory.
 
@@ -452,7 +454,7 @@ like... you know. a _virtual_ file system?
 
     % id = "01JDJGVC7BVV81GF2GRTQVCK7E"
     - there is one flaw I want to point out with the current implementation of `Dir`: it uses trait methods to add new resource forks.
-    
+
         % id = "01JDJGVC7BJS79G1VJN1G29GRK"
         - any time you add a new resource fork that's implemented only by one or two `Dir`s, you have to duplicate a stub across all existing adapters!
         this means introducing a new fork means performing up to `N` edits, where `N` is the number of implementers of `Dir`.