Karsten Thoms

EASY TO LEARN

FLEXIBLE

GOOD DOCS

HIDES COMPLEXITY

USES XTEND

GOOD SUPPORTFAST PROTOTYPING

GOOD DEFAULTS

MATURE

SOURCE QUALITY

FLEXIBILITYWho says you can’t play golf with apples?

https://pixabay.com/de/apple-natur-green-garten-947674/

DESIGN SMELLS

GRAMMAR• Assign ‚name=ID‘ attribute for non-referable elements

• Tweaking grammar to optimize non syntax related stuff

• generated meta model structure

• content assist (e.g. whitespace in combined keywords)

• scoping

DESIGN SMELLS

GRAMMAR• Too few / too much keywords

• Trying to solve too much with terminal rules

• Unordered groups for multivalued assignments

• Using Xcore for small metamodels

• Enable backtracking to „solve“ a grammar ambiguity issues

DESIGN SMELLS

GRAMMAR• Too few / too much keywords

• Trying to solve too much with terminal rules

• Unordered groups for multivalued assignments

• Using Xcore for small metamodels

• Enable backtracking to „solve“ a grammar ambiguity issues

DESIGN SMELLS

GRAMMAR• Too few / too much keywords

• Trying to solve too much with terminal rules

• Unordered groups for multivalued assignments

• Using Xcore for small metamodels

• Enable backtracking to „solve“ grammar ambiguity issues

DESIGN SMELLS

AMBIGUITY

SCOPING• Use declarative scope provider

• Navigate cross-references while computing scope

• Compute stuff in scope provider which could be put into IEObjectDescription’s user data

• „Optimize“ scope to tweak content assist

• Check for proxies, resolve proxies

• Instantiate unnecessary objects

• Access node model and assume that it is complete

DESIGN SMELLS

VALIDATION• Don’t use semantic validation at all

• Use @Check without CheckType => Default is CheckType.FAST

• Provide check methods for child-elements which traverse sibling elements (e.g. uniqueness check)

• Many fine grained check methods

• Loading the world again

DESIGN SMELLS

COMPLEXITY

IDENTIFYING THE RIGHT PLACE TO FIX AN ISSUE

https://pixabay.com/de/nadel-im-heuhaufen-nadel-heuhaufen-1752846/

https://pixabay.com/de/yoda-dunkel-die-dunkle-seite-des-1726764/

Use the Source, Luke!

Dependency Injection

CUSTOMIZING

http://de.freeimages.com/photo/chef-s-swiss-knife-1239195

UNEXPECTED

OVER ENGINEERING

DSL OVERLOAD

Entity DSL

ConfigDSL

FrontendDSL

RuleDSL

Style DSL

BehaviorDSL

RequirementsDSL

CoolDSL

YetAnother

DSLPersonalFavorite

DSL

MyDSL

DatabaseDSL

Sample DSL

The Only Right DSL

EXPRESSIONS

DSL != NATURAL LANGUAGE

NON-TECHIE USERS

SCALABILITY

http://de.freeimages.com/photo/constructing-tower-1207408

CODE WASTE

PROTOTYPES

TESTING

STICK WITH OLD RELEASES

ADVICE RESISTANCE

WRONGTOOL

PROBLEM

SOLUTION

• Evaluate if Xtext is the right tool to solve a problem [ it

often is :-) ]

• Get experts on board when starting ambitious projects

• Learn underlying technologies (EMF, ANTLR, …)

• Continuously develop DSL projects

• Write extensive tests

• Invest into user experience

AVOIDING TROUBLE

KEEP INFORMED

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