Packages

  • package root

    Documentation/API for the Molecule library - a meta DSL for the Datomic database.

    Manual | scalamolecule.org | Github | Forum

    Definition Classes
    root
  • package molecule

    Molecule library - a Scala meta-DSL for the Datomic database.

    Molecule library - a Scala meta-DSL for the Datomic database.

    See api package for various api imports to start using Molecule.

    Sub-packages

    action Actions on molecules and entities.
    api Molecule import interfaces of various arities.
    ast Internal Molecule ASTs.
    boilerplate Internal interfaces for auto-generated DSL boilerplate code.
    composition    Builder methods to compose molecules.
    exceptions Exceptions thrown by Molecule.
    expression Attribute expressions and operations.
    facade Molecule facades to Datomic.
    factory Implicit macro methods `m` to instantiate molecules from custom DSL molecule constructs.
    generic Interfaces to generic information about datoms and Datomic database.
    input Input molecules awaiting input.
    macro Internal macros generating molecule code from custom DSL molecule constructs.
    ops Internal operational helpers for transforming DSL to molecule.
    schema Schema definition DSL.
    transform Internal transformers from DSL to Model/Query/Transaction.
    util Internal Java database functions for Datomic.

    Definition Classes
    root
  • package action

    Various actions and operations on molecules and entities.

    Various actions and operations on molecules and entities.

    Definition Classes
    molecule
  • package api

    Public interfaces to be imported to use Molecule.

    Public interfaces to be imported to use Molecule.

    To make the Molecule macro materializations as fast as possible we try to import as few macro implicits as possible. If your application code build molecules with at the most 10 attributes, then you can do the following import to start using Molecule:

    import molecule.api.out10._

    out means "output molecule" , and 10 the maximum arity or number of attributes of your molecules.

    If you use input molecules awaiting an input then you can add inX where X is how many inputs (1, 2 or 3) you will use, for instance:

    import molecule.api.in2_out10._

    This way we keep the implicit macro def lookups to a minimum and compilation speed as fast as possible.

    Arities can be changed anytime you like. But not to a lower arity than that of the molecules you use in scope of the import.

    Definition Classes
    molecule
  • package ast

    Internal Molecule ASTs.

    Internal Molecule ASTs.

    Definition Classes
    molecule
  • package boilerplate

    Internal interfaces for auto-generated DSL boilerplate code.

    Internal interfaces for auto-generated DSL boilerplate code.

    Interfaces to the generated schema-defined DSL boilerplate code that the sbt-plugin generates when doing a sbt-compile. Molecule macros can then type-safely deduct the type structure of composed molecules.

    Definition Classes
    molecule
  • package composition

    Methods to build transaction, composite and nested molecules.

    Methods to build transaction, composite and nested molecules.

    Definition Classes
    molecule
  • package exceptions

    Exceptions thrown by Molecule.

    Exceptions thrown by Molecule.

    Definition Classes
    molecule
  • package expression

    Attribute expressions and operations.

    Attribute expressions and operations.

    Refine attribute matches with various attribute expressions:

    Person.age(42)                           // equality
    Person.name.contains("John")             // fulltext search
    Person.age.!=(42)                        // negation (or `not`)
    Person.age.<(42)                         // comparison (< > <= >=)
    Person.name("John" or "Jonas")           // OR-logic
    Person.age()                             // apply empty value to retract value(s) in updates
    Person.hobbies.assert("golf")               // add value(s) to card-many attributes
    Person.hobbies.retract("golf")            // retract value(s) of card-many attributes
    Person.hobbies.replace("golf", "diving") // replace value(s) of card-many attributes
    Person.tags.k("en")                      // match values of map attributes by key
    Person.age(Nil)                          // match non-asserted datoms (null)
    Person.name(?)                           // initiate input molecules awaiting input at runtime
    Person.name(unify)                       // Unify attributes in self-joins

    Apply aggregate keywords to aggregate attribute value(s):

    // Aggregates on any attribute type
    Person.age(count).get.head         === 3   // count of asserted `age` attribute values
    Person.age(countDistinct).get.head === 3   // count of asserted distinct `age` attribute values
    Person.age(max).get.head           === 38  // maximum `age` value (using `compare`)
    Person.age(min).get.head           === 5   // maximum `age` value (using `compare`)
    Person.age(rand).get.head          === 25  // single random `age` value
    Person.age(sample).get.head        === 27  // single sample `age` value (when single value, same as random)
    
    // Aggregates on any attribute type, returning multiple values
    Person.age(distinct).get.head  === Vector(5, 7, 38)  // distinct `age` values
    Person.age(max(2)).get.head    === Vector(38, 7)     // 2 maximum `age` values
    Person.age(min(2)).get.head    === Vector(5, 7)      // 2 minimum `age` values
    Person.age(rand(2)).get.head   === Stream(5, ?)      // 2 random `age` values (values can re-occur)
    Person.age(sample(2)).get.head === Vector(7, 38)     // 2 sample `age` values
    
    // Aggregates on number attributes
    Person.age(sum).get.head      === 50               // sum of all `age` numbers
    Person.age(avg).get.head      === 16.66666667      // average of all `age` numbers
    Person.age(median).get.head   === 7                // median of all `age` numbers
    Person.age(stddev).get.head   === 15.107025591499  // standard deviation of all `age` numbers
    Person.age(variance).get.head === 228.2222222222   // variance of all `age` numbers
    Definition Classes
    molecule
    See also

    Manual: expressions | aggregates | input molecules

    Tests: expressions

  • package facade

    Molecule facades to Datomic.

    Molecule facades to Datomic.

    Facades are not trying to cover all Datomic methods but rather only interfaces relevant to Molecule.

    Definition Classes
    molecule
  • package factory

    Factory methods m to instantiate molecules from custom DSL molecule constructs.

    Factory methods m to instantiate molecules from custom DSL molecule constructs.

    Definition Classes
    molecule
  • package generic

    Interfaces to meta information about datoms and Datomic database.

    Interfaces to meta information about datoms and Datomic database.

    Definition Classes
    molecule
  • package input

    Input molecules awaiting input.

    Input molecules awaiting input.

    Input molecules are molecules that awaits one or more inputs at runtime. When input value is applied, the input molecule is resolved and a standard molecule is returned that we can then call actions on.

    Input molecule queries are cached by Datomic. So there is a runtime performance gain in using input molecules. Furthermore, input molecules are a good fit for re-use for queries where only a few parameters change.

    Input molecules can await 1, 2 or 3 inputs and are constructed by applying the ? marker to attributes. If one marker is applied, we get a InputMolecule_1, 2 inputs creates an InputMolecule_2 and 3 an InputMolecule_3.

    The three input molecule interfaces come in arity-versions corresponding to the number of non-?-marked attributes in the input molecule. Let's see a simple example:

    // Sample data
    Person.name.age insert List(("Ben", 42), ("Liz", 34))
    
    // Input molecule created at compile time. Awaits a name of type String
    val ageOfPersons: InputMolecule_1.InputMolecule_1_01[String, Int] = m(Person.name_(?).age)
    
    // Resolved molecule. "Ben" input is matched against name attribute
    val ageOfPersonsNamedBen: Molecule.Molecule01[Int] = ageOfPersons.apply("Ben")
    
    // Calling action on resolved molecule.
    // (Only age is returned since name was marked as tacit with the underscore notation)
    ageOfPersonsNamedBen.get === List(42)
    
    // Or we can re-use the input molecule straight away
    ageOfPersons("Liz").get === List(34)
    Definition Classes
    molecule
  • package macros

    Internal macros generating molecule code from custom DSL molecule constructs.

    Internal macros generating molecule code from custom DSL molecule constructs.

    Definition Classes
    molecule
  • package ops

    Internal operational helpers for transforming DSL to molecules.

    Internal operational helpers for transforming DSL to molecules.

    Definition Classes
    molecule
  • package schema

    Schema definition DSL and API.

    Schema definition DSL and API.

    Definition Classes
    molecule
  • SchemaTransaction
  • definition
  • package transform

    Internal transformers from DSL to Model/Query/Transaction/Datomic.

    Internal transformers from DSL to Model/Query/Transaction/Datomic.

    Molecule transforms custom boilerplate DSL constructs to Datomic queries in 3 steps:

    Custom DSL molecule --> Model --> Query --> Datomic query string

    Definition Classes
    molecule
    See also

    http://www.scalamolecule.org/dev/transformation/

  • package util

    Internal Java database functions for Datomic.

    Internal Java database functions for Datomic.

    Definition Classes
    molecule
p

molecule

schema

package schema

Schema definition DSL and API.

Source
package.scala
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Type Members

  1. trait SchemaTransaction extends AnyRef

    Schema transaction interface for auto-generated schema transaction data.

    Schema transaction interface for auto-generated schema transaction data.

    See also

    Manual

Value Members

  1. object definition

    Schema definition DSL.

    Schema definition DSL.

    Define Datomic database schema in a Schema Definition file.

    For small projects, the schema can be defined without partition definitions where all namespaces reside in a default tacit partition:

    package path.to.your.project
    import molecule.schema.definition._       // import schema definition DSL
    
    @InOut(1, 8)                              // Set input/output arity
    object SeattleDefinition {                // Schema definition object
    
      trait Person {                          // Namespace
        val name = oneString.fulltextSearch   // String attribute definition with fulltext search
        val age  = oneInt                     // Int attribute definition
      }
    
      // Additional namespaces...
    }

    For larger projects, it is recommended to group namespaces in partitions:

    package path.to.your.project
    import molecule.schema.definition._
    
    @InOut(3, 15)
    object SeattleDefinition {
    
      object customer {
        trait Person {
          val name    = oneString.fulltextSearch
          val age     = oneInt
          val address = one[Address]
          val bought  = many[products.Item]
        }
        trait Address {
          val street = oneString.fulltextSearch
          val city   = oneInt
        }
        // ..more namespaces in the `customer` partition
      }
    
      object products {
        trait Item {
          val title   = oneString
          val inStock = oneInt
        }
        // ..more namespaces in the `products` partition
      }
    
      // Additional partitions...
    }
    See also

    Manual | Tests: Schema without partitions, Schema with partitions, Bidirectionals

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