Prototyping PADD, the query interface for LCARS.

proto_font.padd

using _ = personal#olive;
using _f = _#typography;
using _et = _#entityType;

ensure _et#typeface;

lhs isSimilarTo rhs = {
  bidirectionalEdge <-similarTo> lhs rhs;
}

_f#fontArial isSimilarTo _f#fontHelvetica;

_f#fontArial do {
  isA _et#typeface;
  prop :publishedAt 1996;
  isSimilarTo _f#Helvetica;
};

# `#` is the comment symbol?
# the file extension ...
#	* maybe ".ll" for *"LCARS List"*
# 	* or ".ns" for *"Newspeak"*
# (".l" is not available, it's for LISP ...)

type id =
  | root
  | levelUp (id, string)

* DB primitive types (lang. basic primitive (intrinsic) type marked with X):
  * `id` X - no DB type
  # * `scope` X - no DB type

  * `string` X - PG DATE (Unicode?)
  * `i16` X - PG SMALLINT
  * `i32` X - PG INT
  * `double` X - PG REAL/FLOAT8
  * `T[]` X - PG ARRAY
  * TODO: numeric/decimal

  * `date` - PG DATE
  * `time` - PG TIME
  * `timestamp` - PG LONG
  * `datetime` - PG TIMESTAMPZ
  * `interval` - PG INTERVAL

  * TODO: `json` - PG JSONB
  * `uuid` - PG UUID
  *  ... well there are so many types ...
* expression:
  * `? ($queryPatterns) { predicates }` - QUERY clause, quasi-SELECT in SQL
  * `$$identifier` - Pattern Variable (explicit for impl. conv.)
  * `let $pattern = $expression` - let-binding

module basis {

  entry entry_base {
    :eid: uuid,
    :id: id,
    :utcCreated: timestamp,

    let constructor (id: id)
      { :id id,
        :eid uuid.generate(),
        :utcCreated timestamp.now() }
  }

  entry Entity: entry_base {
    :name: string;
  }

  entry Edge: entry_base {
  }

  let newAge (): id =
    #edge ## (randomId ())

  entry Tag: entity {

    let constructor (name: string) {

    }

    let create (name: string) =
      #tag ## (name.lowercase) <- Tag name
  }

  entry URL: entity {
    protocol: string;
    href: string;
    title: string;
  }

}

open basis

module media {

  entry Image: entity {
    :name: string,
    :sha1: string,
  }

  entity Sticker: entity {
    :text: string,
    :image: Image,
  }

}

module typography {

  entry Font: entity {

  }

}

module secondwtq {

}

open secondwtq

# To ensure all stuff are synchronized and consistent,
#  only :eid is stored for entites in memory
Tag.create "OCaml";
Tag.create "金馆长";



let fonts = ? ($fontA, $fontB) {
  fontA.publishedAt == 1996 &&
  #namespace#in _f fontA.id &&
  bidirectionalEdgeBetween <-similarTo> fontA fontB
};

---