Am 29.05.20 um 18:03 schrieb Aditya Mahajan:
The magic of loading and reusing them happens behind the scenes, so the user doesn't have to worry about it. See https://wiki.contextgarden.net/System_Macros/Key_Value_Assignments#Multi-pas... for more details.
Now, suppose you wanted to use the image defined as part of `\startchapter` as the background image of the _current_ page, then you could access the value of the \structureuservariable. For example,
\startchapter[title=whatever][image=filename]
\structureuservariable{image}
\stopchapter
But you want to use the value of the image _before_ the start of the chapter. So, Wolfgang is using the two-pass mechanism to store the value of the image in the database named 'chapter` in the hash-location `\ChapterCounter` and then retrieving it before it is defined!
Thanks a lot for the clarification! juh