diff options
Diffstat (limited to 'docs/XmlConfiguration.tex')
| -rw-r--r-- | docs/XmlConfiguration.tex | 124 |
1 files changed, 123 insertions, 1 deletions
diff --git a/docs/XmlConfiguration.tex b/docs/XmlConfiguration.tex index 0ccd08d..6f45de2 100644 --- a/docs/XmlConfiguration.tex +++ b/docs/XmlConfiguration.tex @@ -19,7 +19,7 @@ same way you might write a webpage in HTML. We will refer to the XML system here-on-in as `SmootConf'. \textbf{The fastest way to get familiar with SmootConf is simply to look at the XML files in the configuration file. However, if you want a more structured approach to - its feature and sublties this document should do the job.} Without any further ado, lets start looking at + its feature and subtleties this document should do the job.} Without any further ado, lets start looking at how this all works. \section{Declaring a class in SmootConf} The most common thing done is SmootConf is declaring a class -- Class declaration code will @@ -98,4 +98,126 @@ </InputElement> </InputConfiguration> \end{verbatim} + \texttt{InputElement}s live under the broader \texttt{InputConfiguration} tag. Thats all in + terms of basic configuration -- all other features are going to be specific to the + particular class you are declaring (and the class should specify those). However, the + system also offers a lot of features to give you more power and flexibility, as well as + minimizing repeated XML. + \section{XML Inheritance} + SmootConf allows you have XML objects inherit from this other. Think of this as an + X:Include crossed with OO style inheritance, if those are familiar concepts. The most basic + tag of inheritance in SmootConf is the \texttt{InheritsFrom} tag. Here is a quick example + of it in action: + \begin{verbatim} + <Renderer Scale="4"> + <InheritsFrom>renderers/Pygame.xml</InheritsFrom> + </Renderer> + \end{verbatim} + + And the contents of \texttt{renderers/Pygame.xml}: + \begin{verbatim} + <Renderer> + <Class>renderers.PygameRenderer</Class> + <Args> + <Id>pygamerender</Id> + <displaySize>(1300,50)</displaySize> + </Args> + </Renderer> + \end{verbatim} + + The \texttt{InheritsFrom} tag indicates to look in the XML File indicated, parse it, and + recursively merge its tags with the siblings of the \texttt{InheritsFrom} tag. From a high + level, the algorithm works as follows: + + \begin{itemize} + \item For every tag: + \item If the tag is in the inheriter, use that. Otherwise, use the inherited tag. + \item Recurse to children. + \end{itemize} + + SmootConf adds a bit of syntactic sugar that allows you override args in the args dict when + doing inheritance by simply specifying them as attributes of the parent. The example below + comes from a pixel layout config: + \begin{verbatim} + <PixelConfiguration> + <PixelStrip Id="strip1.1" originLocation="(0,0)" Reverse="True"> + <InheritsFrom>layouts/50PixelStrip.xml</InheritsFrom> + </PixelStrip> + <PixelStrip Id="strip1.2" originLocation="(200,0)"> + <InheritsFrom>layouts/50PixelStrip.xml</InheritsFrom> + </PixelStrip> + \end{verbatim} + + The contents of \texttt{layouts/50PixelStrip.xml} are: + \begin{verbatim} + <PixelStrip> + <Class>layouts.LineLayout</Class> + <Args> + <pixelToPixelSpacing>4</pixelToPixelSpacing> + <spacing>4</spacing> + <numPixels>50</numPixels> + </Args> + </PixelStrip> + \end{verbatim} + + A careful reading of the algorithm will reveal some behaviors which are not specified. What if there are + multiple instances of identical sibling tags? The answer is that this is not currently + supported. It may be supported in the future. + + If you want your tags to be added to an inherited config without trying to merge, put them + in an \texttt{APPEND} tag like so: + + \begin{verbatim} + <Behaviors> + <InheritsFrom>behaviors/StockBehaviors.xml</InheritsFrom> + <APPEND> + <Beavhior> + <InheritsFrom>behaviors/SomethingElse.xml</InerhitsFrom> + </Behavior> + <Behavior> + <Class>blah.blah</Class> + <Args> + </Args> + </Behavior> + </APPEND> + </Behaviors> + \end{verbatim} + \section{Variable Bindings} + SmootConf allows developers to reference other variables within the \texttt{<Args>} tag. These + references are dynamic, and are bound for the lifetime of the object and will updated as + their bound values update. Here is an example: + \begin{verbatim} + <Behavior> + <Class>behaviors.SomeClass</Class> + <Args> + <Id>dimming</Id> + <DecayCoefficient>${DecayTime}$*5</DecayCoefficient> + <DecayTime>10</DecayTime> + </Args> + </Behavior> + \end{verbatim} + In this (fake) example, we bind the DecayCoefficient to the value of DecayTime, which allows us to + set decay in a reasonable unit, decoupled from the coefficient required by the behavior + itself. + + Under the hood, this feature is done with lambda functions. When you query arguments on the + object, the lambda gets resolved (look at \texttt{operationscore/SmootCoreObject.py} for the + implementation of this). Because of this, we also have to ability to go 1 layer deeper. + + Let's say you wanted to operate on another dictionary -- say, the current behavior packet or + and args of another behavior. By surrounding your variable in quotes, querying its value + with product a lambda function, which, when given another dictionary, will resolve the + value. + \begin{verbatim} + <Behavior> + <Class>behaviors.SomeClass</Class> + <Args> + <Id>stayinbounds</Id> + <MaxX>100</MaxX> + <OutOfBounds>'${x}$' < ${MaxX}$</OutOfBounds> + </Args> + </Behavior> + \end{verbatim} + If you call \texttt{self['OutOfBounds']}, and pass it a dictionary with a value at key + \texttt{x}, it will return a boolean stating whether or not \texttt{x > MaxX}. \end{document} |