This post is about creating a server side z-code
interpreter that represents game progress in the URI. Try it with the game Lost
Pig.
I enjoy working on URIs and have the mug to prove it. Along those lines I've combined thoughts on URIs with interactive fiction. I have a limited amount of experience with Inform which generates Z-Code so I'll focus on pieces written in that. Of course we can already have URIs identifying the Z-Code files themselves, but I want URIs to identify my place in a piece of interactive fiction. The proper way to do this would be to give Z-Code its own mimetype and associate with that mimetype the format of a fragment that would contain the save state of user's interactive fiction session. A user would install a browser plugin that would generate URIs containing the appropriate fragment while you play the IF piece and be able to load URIs identifying Z-Code files and load the save state that appears in the fragment.
But all of that would be a lot of work, so I made a server side version that approximates this. On the Web Frotz Interpreter page, enter the URI of a Z-Code file to start a game. Enter your commands into the input text box at the bottom and you get a new URI after every command. For example, here's the beginning of Zork. I'm running a slightly modified version of the Unix version of Frotz. Baf's Guide to the IF Archive has lists of IF games to try out.
There are two issues with this thought, the first being the security issues with running arbitrary z-code and the second is the practical URI length limit of about 2K in IE. From the Z-Code standard and the Frotz source it looks like 'save' and 'restore' are the only commands that could do anything interesting outside of the Z-Code virtual machine. As for the length-limit on URIs I'm not sure that much can be done about that. I'm using a base64 encoded copy of the compressed input stream in the URI now. Switching to the actual save state might be smaller after enough user input.
I saw this odd looking cute cat and it reminded me of Thom Yorke. On a related note also see the myth buster lol-cat.
Also I think the whistling puppy (~0:05) and hungry lumas transforming on Super Mario Galaxy (~0:15) sound very similar.
IPv6 address syntax consists of 8 groupings of colon delimited 16-bit hex values making up the 128-bit address. An optional double colon
can replace any consecutive sequence of 0 valued hex values. For example the following is a valid IPv6 address: fe80::2c02:db79
Some IPv6 addresses aren't global and in those cases need a scope ID to describe their context. These get a '%' followed by the scope ID.
For example the previous example with a scope ID of '8' would be: fe80::2c02:db79%8
IPv6 addresses in URIs may appear in the host section of a URI as long as they're enclosed by square brackets. For example:
http://[fe80::2c02:db79]/. The RFC explicitly notes that there isn't a way to add a scope ID to the IPv6 address in a URI. However a draft document describes adding
scope IDs to IPv6 addresses in URIs. The draft document uses the IPvFuture production from the URI RFC with a 'v1' to add a new
hostname syntax and a '+' instead of a '%' for delimiting the scope id. For example: http://[v1.fe80::2c02:db79+8]/. However, this is still a draft document, not a final
standard, and I don't know of any system that works this way.
In Windows XPSP2 the IPv6 stack is available but disabled by default. To enable the IPv6 stack, at a command prompt run 'netsh interface ipv6 install'. In Vista IPv6 is the on by default and cannot be turned off, while the IPv4 stack is optional and may be turned off by a command similar to the previous.
Once you have IPv6 on in your OS you can turn on IPv6 for IIS6 or just use IIS7. The address ::1 refers to the local machine.
In some places in Windows like UNC paths, IPv6 addresses aren't allowed. In those cases you can use a Vista DNS IPv6 hack that lives in the OS
name resolution stack that transforms particularly crafted names into IPv6 addresses. Take your IPv6 address, replace the ':'s with '-'s and the '%' with an 's' and then append '.ipv6-literal.net'
to the end. For example: fe80--2c02-db79s8.ipv6-literal.net. That name will resolve to the same example I've been using in Vista. This transformation occurs inside the system's local
name resolution stack so no DNS servers are involved, although Microsoft does own the ipv6-literal.net domain name.
MSDN describes IPv6 addresses in URIs in Windows and I've described IPv6 addresses in URIs in IE7. File URIs in
IE7 don't support IPv6 addresses. If you want to put a scope ID in a URI in IE7 you use a '%25' to delimit the scope ID and due to a bug you must have at least two digits in your scope ID. So,
to take the previous example: http://[fe80::2c02:db79%2508]/. Note that its 08 rather than just 8.
which command is a rather literal port and requires you to enter the entire name of the command for which you're looking. That is 'which which' won't find itself but
'which which.exe' will. This makes this almost useless for me so I thought to write my own as a batch file. I had learned about a few goodies available in cmd.exe that I thought would
make this an easy task. It turned out to be more difficult than I thought.for /F "usebackq tokens=*" %%a in ( `"echo %PATH:;=& echo %"` ) do (
for /F "usebackq tokens=*" %%b in ( `"echo %PATHEXT:;=& echo %"` ) do (
if exist "%%a"\%1%%b (
for %%c in ( "%%a"\%1%%b ) do (
echo %%~fc
)
)
)
)PATH and PATHEXT hold the list of paths to search through to find commands, and the extensions of files that should be run as
commands respectively. The 'for /F "usebackq tokens=*" %%a in (...) do (...)' runs the 'do' portion with %%a sequentially taking on the value of every line in
the 'in' portion. That's nice, but PATH and PATHEXT don't have their elements on different lines and I don't know of a way to escape a newline character to
appear in a batch file. In order to get the PATH and PATHEXT's elements onto different lines I used the %ENV:a=b% syntax which replaces occurrences of a with b
in the value of ENV. I replaced the ';' delimiter with the text '& echo ' which means %PATHEXT:;=& echo% evaluates to something like "echo
.COM& echo .EXE& echo .BAT& ...". I have to put the whole expression in double quotes in order to escape the '&' for appearing in the batch file. The usebackq and
the backwards quotes means that the backquoted string should be replaced with the output of the execution of its content. So in that fashion I'm able to get each element of the env. variable onto new
lines. The rest is pretty straight forward.C:\Users\davris>which.cmd *hi*
C:\Windows\System32\GRAPHICS.COM
C:\Windows\System32\SearchIndexer.exe
D:\bin\which.exe
D:\bin\which.cmd
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