practical code generation

http://europe.cfunited.com/ March 12 & 13, 2007

Practical Code GenerationPractical Code Generation

Peter BellSystemsForge

March 12 & 13, 2007http://europe.cfunited.com/

OverviewOverviewWho am I?

Why Listen?

Problems to solve

Potential solutions

Domain Specific Languages

Software Product Lines

Code Gen/Frameworks

Next Steps

March 12 & 13, 2007http://europe.cfunited.com/

Who Am I?Who Am I?Programmer - 30-40 projects/yr.

Researcher - Published academic papers DSM forum/ooPSLA

Entrepreneur - Profitable/practical

SystemsForge - 10,000 custom apps/yr.

Writer - CFDJ, Fusion Authority Quarterly

Presenter - cf.objective(), CF United, Frameworks, Code Generation 2007, ooPSLA, Domain Specific Modeling Forum, CFCamp . . .

March 12 & 13, 2007http://europe.cfunited.com/

Why Listen?Why Listen?

Companies are reporting 5-10x faster development using Domain Specific Languages and Software Product Lines

You’re already doing these things

A few concepts will help you to do them better

March 12 & 13, 2007http://europe.cfunited.com/

CalibrationCalibration

Have you:

Written OO code?

Heard of DSLs?

Written a DSL?

Heard of SPLs

Created a SPL?

March 12 & 13, 2007http://europe.cfunited.com/

ProblemsProblems

OO coding is slow

Changes are painful

Reuse is difficult

March 12 & 13, 2007http://europe.cfunited.com/

OO Coding is SlowOO Coding is Slow

ProductService.cfc

ProductDAO.cfc

Product.cfc

tbl_Product

ColdSpring/Lightwire config

Admin controller/views

Front end controller

Catalog.cfc

Front end views

ProductList.cfm, ProductDetail.cfm

Add Products to site . . .

March 12 & 13, 2007http://europe.cfunited.com/

Changes are PainfulChanges are Painful

Add services from tbl_Service to product catalog

Products -> multiple categories

Change form error handling (error list to in-form display)

March 12 & 13, 2007http://europe.cfunited.com/

Re-use is DifficultRe-use is DifficultLibraries/utility components/cut and paste/snippets - usually OK

Problem with cfc reuse is usually cross cutting concerns:

Logging

Error handlers

Notification services

Other dependencies . . .

March 12 & 13, 2007http://europe.cfunited.com/

Solving Same ProblemsSolving Same Problems

Solutions

Content management

Workflow

Shopping carts

Techniques

Form processing

DB access

Paginated lists

Reporting

Imports/Exports

March 12 & 13, 2007http://europe.cfunited.com/

Potential SolutionsPotential Solutions

Code quicker - DSL

Maintain easier - DSL

Re-use better - SPL

March 12 & 13, 2007http://europe.cfunited.com/

Domain Specific LanguageDomain Specific Language

“An executable language targeted to a specific problem domain”

Specific - can’t do everything

Executable - not just conceptual

Raising level of abstraction

March 12 & 13, 2007http://europe.cfunited.com/

Types of DSLsTypes of DSLsHorizontal (tech focused)

SQL

RegEx

Import description language

General workflow language

Vertical (business focused)

Insurance policy language

Product configuration language

Academic requirements language

March 12 & 13, 2007http://europe.cfunited.com/

Types of DSLs - InternalTypes of DSLs - Internal

Custom tag

<cf_import filename="test.csv" record-delimiter="," field-name-list="FirstName,LastName,Email" source="tbl_User" method="update">

API

UserService.import("test.csv", ",", "FirstName,LastName,Email", "tbl_User", "update");

Method Chaining

User.IsValid.FirstName()

March 12 & 13, 2007http://europe.cfunited.com/

Types of DSL - ExternalTypes of DSL - ExternalComma delimited

"test.csv", ",", "FirstName,LastName,Email", "tbl_User", "update"

XML

<import filename="test.csv" record-delimiter="," field-name-list="FirstName,LastName,Email" source="tbl_User" method="update" />

Databased

“Little Language”

Import test.csv using commas update tbl_User with FirstName,LastName,Email

Visual

March 12 & 13, 2007http://europe.cfunited.com/

DSL Key ConceptDSL Key ConceptAbstract Grammar vs. Concrete Syntax

What you say vs. How you say it

User@FirstName

<cfset Objects.User.Title = “User”><cfset Objects.User.Attributes.Name = “FirstName”>

<Object title=”User”> <Name>FirstName</Name></Object>

March 12 & 13, 2007http://europe.cfunited.com/

Example DSLExample DSLProduct extends: BaseObject tableName: tbl_ProductIdentity: ProductID

Properties: Title title required Price money optional default:0 Description WYSIWYG optional

ClassMethods: AdminList: Title,Price OrderBy Title DefaultAdd: Title,Price,Description QuickAdd: Title,Price multiple:5 DefaultEdit: ID, Title,Price,Description

Relationship has-many Category associated optional

March 12 & 13, 2007http://europe.cfunited.com/

Benefits of DSLsBenefits of DSLs

More concise (less to write/edit)

Can add constraints

MAY be end user editable

March 12 & 13, 2007http://europe.cfunited.com/

Software Product LinesSoftware Product LinesDesign a collection of applications

Bounded and unbounded variability

Bounded: feature model/configuration

Unbounded: DSLs

Extension points

March 12 & 13, 2007http://europe.cfunited.com/

Code Gen/FrameworkCode Gen/Framework

Both use DSLs

Compiled/interpreted

Late bound decision

March 12 & 13, 2007http://europe.cfunited.com/

Next StepsNext StepsMultiple Applications?

Plan variability

Feature model

Configuration options

DSLs

Generators/framework

Single Application?

Reusable services

Raise abstraction levels

DSLs: Custom tags, APIs, external config files, CMSs, visual editors (Eclipse EMF)

March 12 & 13, 2007 22

http://europe.cfunited.com/

Questions?Questions?

Blog: www.pbell.com

Email: peter@pbell.com

Yahoo: freshstartsw

AIM: appgeneration