At the moment, I implemented some basic types (BOOL, WORD, INT, CHAR, LPWSTR) and some common synonyms (UINT, DWORD, LONG). I also added a POINT type which basically writes an array [x, y] to two INTs.
To define a DataType, you just need to specify its size in bytes and a getter and setter method. For example, INT is defined with size 4 and two methods which simply map to ReadDWORD and WriteDWORD. For LPWSTR, the getter method uses some functions from kernel32 to get the string length of the pointer, then copy its contents and read it. The setter simply creates a DataBloc storing the given string and writes the pointer to that block.
This can still be extended upon though, I'm thinking about adding the possibility to use other StructTypes as DataTypes. For example, a NMLISTVIEW structure has an NMHEADER structure for its first 16 bytes. Instead of redefining the NMHEADER members in the NMLISTVIEW definition, it can be easier to just use NMHEADER as the data type of the first member hdr.
Ultimately, you should be able to just copy-paste the structure definitons from MSDN and rewrite it to produce a valid JavaScript hash with keys and data types. I'm not there yet, but even in this early stage it made my life much easier while working on the new ListView class!
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