Embedded Domain-Specific Languages

Embedded Domain-Speciﬁc Languages Anthony M. Sloane Programming Languages Research Group
Department of Computing Macquarie University [email protected] @inkytonik 1 / 16

General-Purpose Language (GPL) 2 / 16

Domain-Speciﬁc Language (DSL) A language that is focused on a
particular problem domain Notations that domain experts know Constructs and abstractions that may not be GPL-compatible Analysis, veriﬁcation, optimisation, transformation can rely on domain knowledge Not necessarily executable <html > <head > <title >SAWDAP Workshop Program </title > </head > <body > ... </body > </html > 3 / 16

Structured Data Processing Relational database tables Structured Query Language (SQL)
SELECT * FROM Purchases WHERE price >= 50.00 ORDER BY description; 4 / 16

Hadoop: API for the Map-Reduce Domain Apache, hadoop.apache.org Main access
via Java API Hive DSL (hive.apache.org) compiles SQL-like code to Hadoop 5 / 16

External vs Internal Domain-Speciﬁc Language External DSL DSL Program DSL
Compiler Target Program Target Program Problem Input Problem Output Internal/Embedded DSL (Shallow) Host Program Host Compiler Target Program DSL Program Host Library DSL Library 6 / 16

Kiama: Shallow Embedding of Software Language Processing in Scala val
beta = rule { case App (Lam (x, t, e1), e2) => Let (x, t, e2 , e1) } val lambda = beta + arithop + subsNum + subsVar + subsApp + subsLam + subsOpn def innermost (s : => Strategy) : Strategy = all (innermost (s) <* attempt (s <* innermost (s))) lazy val s : Strategy = innermost (lambda) Macquarie University, kiama.googlecode.com 7 / 16

Internal/Embedded DSL (Deep) Host Program Host Compiler DSL Compiler DSL
Program Problem Conﬁg DSL Compiler Target Program Target Program Problem Input Problem Output 8 / 16

Scoobi: Deep Embedding of Hadoop Computations val lines = fromTextFile
("hdfs ://in /...") val counts = lines.mapFlatten (_.split (" ")) .map (word => (word , 1)) .groupByKey .combine (Sum.int) counts.toTextFile ("hdfs :// out /...", overwrite=true). persist ( ScoobiConfiguration ()) Uses Kiama for analysis and optimisation NICTA, github.com/NICTA/scoobi 9 / 16

Abstract vs Concrete Domains Hadoop-based DSLs data represented by standard
primitives and generic collections operations are generic mapping, reducing, etc over collections solutions to many problems from many concrete domains can be expressed in this way solutions are abstract compared to the problem domain Concrete DSLs based on data types found in the domain operations are custom for the domain targeted at a particular concrete domain solutions are highly speciﬁc to the domain 10 / 16

Chisel: A More Concrete Domain-Speciﬁc Language Deep embedding of hardware
speciﬁcation class GCD extends Module { val io = new Bundle { val a = UInt(INPUT , 16) val b = UInt(INPUT , 16) val e = Bool(INPUT) val z = UInt(OUTPUT , 16) val v = Bool(OUTPUT) } val x = Reg(UInt ()) val y = Reg(UInt ()) when (x > y) { x := x - y } unless (x > y) { y := y - x } when (io.e) { x := io.a; y := io.b } io.z := x io.v := y === UInt (0) } Berkeley, chisel.eecs.berkeley.edu 11 / 16

Delite: High Performance DSL Implementation Stanford, EPFL, stanford-ppl.github.io/Delite/ 12 /
16

OptiMesh: DSL for Mesh-based Computation Delite-based implementation customises a generic
computation to a particular mesh structure, including analysis for parallelisation. for (edge <- edges (mesh)) { val flux = flux_calc (edge) val v0 = head (edge) val v1 = tail (edge) Flux (v0) += flux Flux (v1) -= flux } Supports complex partial diﬀerentiation equation systems over these mesh structures. 13 / 16

Delite-based DSL Performance Compared to C++ OptiQL: SQL-like queries using
a standard benchmark OptiGraph: static graph analysis on Google’s PageRank algorithm OptiMesh: shallow water simulation 14 / 16

Conclusion Programming language people know how to embed languages Start
with shallow embedding while language is designed Move to deep embedding to add analysis, optimisation, code generation Domain experts know the problem domain Identify the key concepts, data and operations for their problems Together Rapidly prototype embedded languages for new domains Develop optimised implementations as applications grow 15 / 16

Other Credits Relational database table and SQL example: Wikipedia FORTRAN
board game: Christian Hammond on Flickr MapReduce flow diagram: Lukas Kaestner on Flickr Delite figures from Delite: A Compiler Architecture for Performance-Oriented Embedded Domain-Specific Languages by Sujeeth et al, ACM Transactions on Embedded Systems, 13(4), March 2014. 16 / 16

Embedded Domain-Specific Languages

Embedded Domain-Specific Languages

Tony Sloane

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Embedded Domain-Speciﬁc Languages Anthony M. Sloane Programming Languages Research Group

General-Purpose Language (GPL) 2 / 16

Domain-Speciﬁc Language (DSL) A language that is focused on a

Structured Data Processing Relational database tables Structured Query Language (SQL)

Hadoop: API for the Map-Reduce Domain Apache, hadoop.apache.org Main access

External vs Internal Domain-Speciﬁc Language External DSL DSL Program DSL

Kiama: Shallow Embedding of Software Language Processing in Scala val

Internal/Embedded DSL (Deep) Host Program Host Compiler DSL Compiler DSL

Scoobi: Deep Embedding of Hadoop Computations val lines = fromTextFile

Abstract vs Concrete Domains Hadoop-based DSLs data represented by standard

Chisel: A More Concrete Domain-Speciﬁc Language Deep embedding of hardware

Delite: High Performance DSL Implementation Stanford, EPFL, stanford-ppl.github.io/Delite/ 12 /

OptiMesh: DSL for Mesh-based Computation Delite-based implementation customises a generic

Delite-based DSL Performance Compared to C++ OptiQL: SQL-like queries using

Conclusion Programming language people know how to embed languages Start

Other Credits Relational database table and SQL example: Wikipedia FORTRAN