Domain-Specific Languages

Tijs van der Storm

Monday, January 23, 12

Some facts

Robert Glass, Facts and fallacies of Software Engineering, Addison-Wesley 2003

Monday, January 23, 12

Reuse?

Monday, January 23, 12

Reuse?

Monday, January 23, 12

Reuse?

Monday, January 23, 12

Reuse?

Domain Specific Languages!

Monday, January 23, 12

Domain specific languages

Monday, January 23, 12

Domain specific languages

Monday, January 23, 12

Observations

• Special purpose

• Restricted

• Concise

• Expert usage

• Formalized

• Textual or graphic or combination

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General purpose languages (GPLs)

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DSLs

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Programming

CodeDomain Programmer

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Programming

Domain CodeProgrammer

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Programming is “lossy”

• encoding

• obfuscating

• encrypting

• dispersing

• tangling

• distorting

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Time consuming

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Change is error-prone

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Cognitive distance

?

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Design reuse is hard

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Design reuse

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The problem

• a lot of code,

• low level code,

• characterized by lack of abstraction

• encoding domain knowledge

• and encoding design knowledge

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Abstraction

Mondrian’s Pier and OceanPier and ocean

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Modeling the domain

Ceci n’est pas une vache

domain analysis

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System families

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Domain Specific Languages

formalizednotation capturing “Cows”

=

variationpoints

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Domain Specific Languages

grammar,template,

metamodel=

sentence,instance,model

=

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Code generation

Code generator Code

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APT: numerical controlfrom

the ’50s (!)

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SDF: Syntax definitionDeveloped

at CWI/UvA

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LaTeX: document preparation

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VHDL: hardware description

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Risla: financial productsDeveloped

at CWIproduct LOAN

declaration contract data PAMOUNT : amount %% Principal Amount STARTDATE : date %% Starting date MATURDATE : date %% Maturity data INTRATE : int-rate %% Interest rate RDMLIST := [] : cashflow-list %% List of redemptions.

information PAF : cashflow-list %% Principal Amount Flow IAF : cashflow-list %% Interest Amount Flow

registration %% Register one redemption. RDM(AMOUNT : amount, DATE : date)

Time to market went down from 3 months to 3 weeks.

Monday, January 23, 12

Other examples• Make: software building

• Dot: graph visualization

• SQL: relational querying

• SWUL: Swing GUIs

• HTML: hypertext

• CLOPS: commandline options

• GNUPlot: plotting

• R: statistics

• CML: kernel config

• Lex: lexical scanning

• Excel: spreadheets

• Rascal: meta-programming

• ...

Monday, January 23, 12

DSL Implementation

Monday, January 23, 12

DSL Code

cow spots false color orangeend

cow spots true color brownend

cow spots true color blackend

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Embedding

cow spots false color orangeend

cow do spots false color :orangeend

(cow spots #t color 'orange)

new Cow() .spots(false) .color("orange").end();

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Advantages

• No need to write/maintain parser

• Host language available if needed

• Use of existing tools (IDE) etc.

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Drawbacks

• Restricted to host language

• Less static checking

• Less opportunity for optimization/analysis

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Syntax definition

Cow ::= “cow” Prop* “end”Prop ::= “horns” Bool | “spots” Bool | “color” ColorBool ::= “true” | “false”Color ::= “black” | “brown” | “orange”

Repetition

literal

alternative

Monday, January 23, 12

Parser generation

Cow ::= “cow” Prop* “end”Prop ::= “horns” Bool | “spots” Bool | “color” ColorBool ::= “true” | “false”Color ::= “black” | “brown” | “orange”

javacupantlrRats!

yaccbisonlemon

parse.exe

Grammar Parser

Monday, January 23, 12

Parsing

cow spots false color orangeend

parse

whitespaceomitted

Cow

Prop*

Prop Prop

Bool Color“spots” “color”

“orange”“false”Monday, January 23, 12

Abstract syntax tree (AST)

spots color

orangefalse

CowCow

Prop*

Prop Prop

Bool Color“spots” “color”

“orange”“false”

implode

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Semantic analysis

spots color

orangetrue

Cow

check

Constraint:

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Code generation

generatespots color

orangefalse

Cow

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• Parser generators

• Attribute grammar systems

• Transformation systems

• Language workbenches

Tools

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Rascal

• parsing

• analysis

• transformation

• generation

Monday, January 23, 12