Auto-generate FormattingOptions.ceylon

[lucaswerkmeister]

FormattingOptions.ceylon contains a lot of duplicate code; nearly the whole file could be auto-generated from the following information per attribute:

• Documentation
• Type
• Name
• Default value

e.g., for indentMode,

The indentation mode of the formatter.
IndentMode
indentMode
Spaces(4)

would be sufficient. From this, we would then generate

• "<doc>" shared formal <type>? <name>; for SparseFormattingOptions;

• shared actual formal <type> <name>; for FormattingOptions;

  shared actual <type> <name> {
    for (options in decoration) {
        if (exists <name> = options.<name>) {
            return <name>;
        }
    }
    return foundation.<name>;
  }

  for CombinedFormattingOptions;

• <name> = <default> for defaultOptions.

The tree-related classes of ceylon-spec are auto-generated using an ANTLR grammar (treegen); we could do something similar here.

[lucaswerkmeister]

I don't know if it makes a lot of sense to use ANTLR there, though...

[lucaswerkmeister]

For convenience, I'm putting the currently generated version of the file into the wiki here. I'll try and update it from time to time.