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


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 . . .


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


CalibrationCalibration

Have you:

Written OO code?

Heard of DSLs?

Written a DSL?

Heard of SPLs

Created a SPL?


ProblemsProblems

OO coding is slow

Changes are painful

Reuse is difficult


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 . . .


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)


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 . . .


Solving Same ProblemsSolving Same Problems

Solutions

Content management

Workflow

Shopping carts

Techniques

Form processing

DB access

Paginated lists

Reporting

Imports/Exports


Potential SolutionsPotential Solutions

Code quicker - DSL

Maintain easier - DSL

Re-use better - SPL


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


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


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()


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


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>


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


Benefits of DSLsBenefits of DSLs

More concise (less to write/edit)

Can add constraints

MAY be end user editable


Software Product LinesSoftware Product LinesDesign a collection of applications

Bounded and unbounded variability

Bounded: feature model/configuration

Unbounded: DSLs

Extension points


Code Gen/FrameworkCode Gen/Framework

Both use DSLs

Compiled/interpreted

Late bound decision


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: [email protected]

Yahoo: freshstartsw

AIM: appgeneration

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