I like the idea of QR codes, encoding URLs and placing them
on real world objects, but the QR codes themselves are kind of ugly. To make them less obvious I thought I could spray QR codes on to an object with an infrared reflective paint and shine infrared
light on the QR codes, since most cameras, for instance the camera in my G1 phone, pick up infrared that our eyes do not.
In my search for infrared paint I've found a seller of IR ink (via programming forum) and an Infrared Paint Recipe (via IR FAQ).
In looking for this paint I've found that it comes up a lot in relation to the military for things like paint markers that are visible at night with proper equipment, and paint that absorbs IR light to make vehicles less obvious to night vision goggles. Even though the first reflects infrared light and the second absorbs it websites end up refering to both as infrared paint which made it difficult to search.
Additionally I found links to some other geeky infrared projects:
On Monday in Germany we went to Marienplatz and wandered around
the Christmas Market, some of the stores, had drinks in a little pub, visited the Toy Museum, and checked out an impressive looking church. We accidentally drew in some other tourists as we stood
gaping at the Glockenspiel tower waiting for the little show to begin at the wrong hour. That night Megan and Oliver came by our hotel and took us out to a traditional Bavarian restaurant and
brewery that had been brewing beer there for hundreds of years. It was fun although we may have kept Megan and Oliver out too late on a weeknight.
The next day we went to the Deutsches Museum the largest science and technology museum in the world. And indeed it is very large, six floors
on a large grounds. I needed to better pace myself: I spent too much energy being interested in the engineering sections with steam engines, mining, aerospace etc. I was completely worn out by the
time we got to physics, chemistry, etc. etc. and we didn't even look in the natural sciences section. Anyway, its very large. That night we ate with Jon at an Italian restaurant. During the meal
two period dressed children came in and began singing then tried to shake down their captive audience in the restaurant asking for money. The man at the table next to us asked one of the children
what charity the money was going towards, the child said they kept the money, and the man said never mind then and sent the child away.
PowerShell gives us a real CLI for Windows based around .Net stuff. I don't like the creation of a new shell language but I suppose it makes sense given that they want something C# like but not C# exactly since that's much to verbose and strict for a CLI. One of the functions you can override is the TabExpansion function which is used when you tab complete commands. I really like this and so I've added on to the standard implementation to support replacing a variable name with its value, tab completion of available commands, previous command history, and drive names (there not restricted to just one letter in PS).
Learning the new language was a bit of a chore but MSDN helped. A couple of things to note, a statement that has a return value that you don't do anything with is implicitly the return value for the current function. That's why there's no explicit return's in my TabExpansion function. Also, if you're TabExpansion function fails or returns nothing then the builtin TabExpansion function runs which does just filenames. This is why you can see that the standard TabExpansion function doesn't handle normal filenames: it does extra stuff (like method and property completion on variables that represent .Net objects) but if there's no fancy extra stuff to be done it lets the builtin one take a crack.
Here's my TabExpansion function. Probably has bugs, so watch out!
function EscapePath([string] $path, [string] $original)
{
if ($path.Contains(' ') -and !$original.Contains(' '))
{
'"' $path '"';
}
else
{
$path;
}
}
function PathRelativeTo($pathDest, $pathCurrent)
{
if ($pathDest.PSParentPath.ToString().EndsWith($pathCurrent.Path))
{
'.\' $pathDest.name;
}
else
{
$pathDest.FullName;
}
}
# This is the default function to use for tab expansion. It handles simple
# member expansion on variables, variable name expansion and parameter completion
# on commands. It doesn't understand strings so strings containing ; | ( or { may
# cause expansion to fail.
function TabExpansion($line, $lastWord)
{
switch -regex ($lastWord)
{
# Handle property and method expansion...
'(^.*)(\$(\w|\.) )\.(\w*)$' {
$method = [Management.Automation.PSMemberTypes] `
'Method,CodeMethod,ScriptMethod,ParameterizedProperty'
$base = $matches[1]
$expression = $matches[2]
Invoke-Expression ('$val=' $expression)
$pat = $matches[4] '*'
Get-Member -inputobject $val $pat | sort membertype,name |
where { $_.name -notmatch '^[gs]et_'} |
foreach {
if ($_.MemberType -band $method)
{
# Return a method...
$base $expression '.' $_.name '('
}
else {
# Return a property...
$base $expression '.' $_.name
}
}
break;
}
# Handle variable name expansion...
'(^.*\$)([\w\:]*)$' {
$prefix = $matches[1]
$varName = $matches[2]
foreach ($v in Get-Childitem ('variable:' $varName '*'))
{
if ($v.name -eq $varName)
{
$v.value
}
else
{
$prefix $v.name
}
}
break;
}
# Do completion on parameters...
'^-([\w0-9]*)' {
$pat = $matches[1] '*'
# extract the command name from the string
# first split the string into statements and pipeline elements
# This doesn't handle strings however.
$cmdlet = [regex]::Split($line, '[|;]')[-1]
# Extract the trailing unclosed block e.g. ls | foreach { cp
if ($cmdlet -match '\{([^\{\}]*)$')
{
$cmdlet = $matches[1]
}
# Extract the longest unclosed parenthetical expression...
if ($cmdlet -match '\(([^()]*)$')
{
$cmdlet = $matches[1]
}
# take the first space separated token of the remaining string
# as the command to look up. Trim any leading or trailing spaces
# so you don't get leading empty elements.
$cmdlet = $cmdlet.Trim().Split()[0]
# now get the info object for it...
$cmdlet = @(Get-Command -type 'cmdlet,alias' $cmdlet)[0]
# loop resolving aliases...
while ($cmdlet.CommandType -eq 'alias') {
$cmdlet = @(Get-Command -type 'cmdlet,alias' $cmdlet.Definition)[0]
}
# expand the parameter sets and emit the matching elements
foreach ($n in $cmdlet.ParameterSets | Select-Object -expand parameters)
{
$n = $n.name
if ($n -like $pat) { '-' $n }
}
break;
}
default {
$varNameStar = $lastWord '*';
foreach ($n in @(Get-Childitem $varNameStar))
{
$name = PathRelativeTo ($n) ($PWD);
if ($n.PSIsContainer)
{
EscapePath ($name '\') ($lastWord);
}
else
{
EscapePath ($name) ($lastWord);
}
}
if (!$varNameStar.Contains('\'))
{
foreach ($n in @(Get-Command $varNameStar))
{
if ($n.CommandType.ToString().Equals('Application'))
{
foreach ($ext in @((cat Env:PathExt).Split(';')))
{
if ($n.Path.ToString().ToLower().EndsWith(($ext).ToString().ToLower()))
{
EscapePath($n.Path) ($lastWord);
}
}
}
else
{
EscapePath($n.Name) ($lastWord);
}
}
foreach ($n in @(Get-psdrive $varNameStar))
{
EscapePath($n.name ":") ($lastWord);
}
}
foreach ($n in @(Get-History))
{
if ($n.CommandLine.StartsWith($line) -and $n.CommandLine -ne $line)
{
$lastWord $n.CommandLine.Substring($line.Length);
}
}
# Add the original string to the end of the expansion list.
$lastWord;
break;
}
}
}
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