Thanks for all of these most helpful replies.
This will work nicely for what I am trying to do. The file is a series of ‘declarations’. I can either chunk on newline followed by a letter, as you suggest. Or I could chunk on newline followed by ‘name =’, as all the declarations start that way - that would allow subsequent lines of the declaration to also be at the start of the line.
I am aiming to do the parsing on the file as it is being edited. Chunking will mean that the parsing does not have to be re-done on parts of the file already parsed. I can track where the edits are, figure out which chunks that overlaps with, and then re-chunk and parse just those.
I am trying to comprehend whether this scheme can be supported by elm/parser. I guess its going to be supported by whatever goes in the ‘context’ of a Parser.Advanced.
I think studying this will probably answer what I am wondering about above.
Beyond a first pass implementation with chunking of ‘declarations’, it would nice if I could have tolerant parsing that goes deeper into the syntax for the purpose of offering context sensitive help. For example, my ‘declarations’ can take a list of properties (name/value pairs), and the possible properties depend on which code generator the model is going to be passed to. Some properties are optional, some are required. If I can parse the property list as it is being edited but skip over any malformed parts of it, then I should be able to see what properties are already defined, and offer up suggestions for those that are not yet defined.