I found some issues with directive definitions:
- I couldn't use `on FIELD_DEFINITION`, I believe because `FIELD` was parsed
first in `executableDirectiveLocation`. I've combined both
`executableDirectiveLocation` and `typetypeSystemDirectiveLocation` into one
function which can reorder them to ensure every directive location gets a fair
chance at parsing.
Not actually to do with directives, some literals weren't being parsed
correctly.
- The GraphQL spec defines list to be `[]` or `[Value]`, but empty literal lists
weren't being parsed correctly because of using `some` instead of `many`.
- The GraphQL spec defines objects to be `{}` or `{Name: Value}`, but empty
literal objects had the same issue.
Fixes#18.
- `Language.GraphQL.Encoder` moved to `Language.GraphQL.AST.Encoder`.
- `Language.GraphQL.Parser` moved to `Language.GraphQL.AST.Parser`.
- `Language.GraphQL.Lexer` moved to `Language.GraphQL.AST.Lexer`.
- All `Language.GraphQL.AST.Value` data constructor prefixes were removed. The
module should be imported qualified.
- All `Language.GraphQL.AST.Core.Value` data constructor prefixes were removed.
The module should be imported qualified.
- `Language.GraphQL.AST.Transform` is now isn't exposed publically anymore.
