Parsing of name.{ in SelectedValue

[glen-84]

SelectedValue ::
    Path
    SelectedObjectValue
    Path . SelectedObjectValue
    SelectedValue | SelectedValue

A SelectedValue of, for example, field.{ a } will begin parsing as a Path due to the Name token. After the period in a PathSegment, another PathSegment is required, but the next token will instead be a LeftBrace token.

Expected a Name-token, but found a LeftBrace-token.

Should we perform a negative lookahead when parsing a PathSegment, so that the period isn't consumed when followed by a left brace, or is there another solution here?

[benjie]

Also don't do SelectedValue | SelectedValue which has both left- and right- recursion; you should split them up so only one recurses:

SelectedValue ::

- SelectedValue | SelectedValueEntry
- `|`? SelectedValueEntry

SelectedValueEntry ::

- Path [lookahead != `.`]
- Path . SelectedObjectValue
- SelectedObjectValue

[benjie]

Also it looks like your markdown has suffered from prettier autoformatting reflecting mistakes in your original formatting - it's important that the definition (Foo ::) and the definition list are separated by a blank line, otherwise they get treated by markdown as a paragraph.

composite-schemas-spec/spec/Appendix A -- Field Selection.md

Lines 342 to 349 in f56a366

	Path :: - < TypeName > . PathSegment - PathSegment
	PathSegment :: - FieldName - FieldName . PathSegment - FieldName < TypeName > .
	PathSegment
	FieldName :: - Name
	TypeName :: - Name

[glen-84]

That's fixed in #63. 🙂