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

    api Molecule API.
    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.
    input Input molecules awaiting input.
    macros Internal macros generating molecule code from custom DSL molecule constructs.
    generic Interfaces to generic information about datoms and Datomic database.
    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 api
    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
    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
    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
    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
  • 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 exception
  • CastHelpers
  • Model2Query
  • Model2Transaction
  • Query2String
  • package util

    Internal database functions for Datomic.

    Internal database functions for Datomic.

    Definition Classes
    molecule
p

molecule

transform

package transform

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

Source
package.scala
See also

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

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Type Members

  1. trait CastHelpers[Tpl] extends Helpers

    Core molecule interface defining actions that can be called on molecules.

    Core molecule interface defining actions that can be called on molecules.

    Generally we could often have made higher-order methods taking a casting function for variating cases. But we prioritize minimizing the macro-generated code as much as possible to lower compile time overhead.

  2. case class Model2Transaction(conn: Conn, model: Model) extends Helpers with Product with Serializable

    Model to transaction transformation.

    Model to transaction transformation.

    See also

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

  3. case class Query2String(q: Query) extends Helpers with Product with Serializable

    Query to Datomic query string transformation.

    Query to Datomic query string transformation.

    Third transformation in Molecules series of transformations from custom boilerplate DSL constructs to Datomic queries:

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

    See also

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

Value Members

  1. object Model2Query extends Helpers

    Model to Query transformation.

    Model to Query transformation.

    Second transformation in Molecules series of transformations from custom boilerplate DSL constructs to Datomic queries:

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

    See also

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

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