API Birds of a Feather, XML

1
API Birds of a Feather, XML

• Robert C. Leif, Ph.D.
• Vice President R D, Newport Instruments
  Ada_Med
• Tel. [phone]
• Email rleif_at_rleif.com
• Web www.newportinstruments.com

2
How do we work together on APIs?

• Commercial developers should provide sources and
  there should be no cost for single and
  educational uses.
• ADA DEVELOPERS COOPERATIVE LICENSE,
  www.newportinstruments.com
• Software Developers Cooperative,
  http//www.softdevelcoop.org/
• http//groups.yahoo.com/group/softdevelcoop/
• GNU licenses include Other forms of licensing
  will be considered.

3
Which Standard(s)?Requirements

• Sources and materials available for free
• On the web
• No hidden patents or unreasonable royalties.
• Operating system independent.
• Must support Windows, Linux, and Macintosh
• Reasonable design
• Standards parsimony
• Create new by reusing old standards.

4
World Wide Web Consortium (W3C)http//www.w3.org/

• Only reasonable choice
• XML eXtensible Markup Language
• Schema Data-Types
• SVG Scalable Vector Graphics
• XForms Forms for the Web
• XSLfo Formatting language
• SOAP Simple Object Access Protocol

5
The Browser will be the GUI

• Eliminates duplicate application programming
  interfaces for the operating system and the web.
• Provides portability between operating systems.
• Open to all.
• Excellent opportunity for Ada!

6
W3C Compound Document Formats Ada program
output

• Combine multiple formats
• XHTML for hypertext
• Extensible HyperText Markup Language
• SVG for graphics
• Scalable Vector Graphics
• SMIL
• Synchronized Multimedia Integration Language
• XForms for forms on the web

7
XML Schema

• Ada button In Strong Typing We Trust
• Best argument for schema vs. DTD.
• XML schema can and should have Ada semantics.
• Need tools for bidirectional translation of
  data-types.
• Goal XML_Io.
• Provides strongly typed output from Ada programs.
• Facilitates development of applications that
  include XML data.
• Permits the use of W3C Designs
• Ada and Web modes

8
Numbers

• Create the same numeric types for both.
• Ecumenical approach use ECMA types.
• http//www.ecma.ch/
• Originally, European Computer Manufacturers
  Association
• Now, ECMA International - European association
  for standardizing information and communication
  systems.

9
Real Types are Primitive
XML Type Source ECMA
float IEEE single- precision 32-bit float32
double IEEE double-precision 64-bit float64
decimal W3C decimal
Minimum of 18 Digits. Pentium uses double extended precision floating point registers. PowerPC uses floating point registers for fixed-point. Minimum of 18 Digits. Pentium uses double extended precision floating point registers. PowerPC uses floating point registers for fixed-point.
10
Integer Types are Derived
Type Derivation Sequence ECMA Min- Inclusive Max- Inclusive
integer -infinity infinity
nonPositiveInteger 0
negativeInteger -1
long Int64 -263 (263) -1
int Int32 -231 (231) -1
short Int16 -215 (215) -1
byte SByte Int8 -27 (27)-1
Derived From decimal fractionDigits 0
11
XML 32 bit Integer Equivalent

• ltsimpleType name"Int32_Type"gt
• ltrestriction base"int"gt
• ltminInclusive value"-2147483648"/gt
• ltmaxInclusive value"2147483647"/gt
• lt/restrictiongt
• lt/simpleTypegt

12
Create Unicode Strings by Addition of fields to
Bounded_String

• Encapsulated in generic packages,
  Ada.Strings.Bounded. Wide_Bounded
• Solution
• Create a generic that instantiates Ada.Strings.
  Wide_Bounded with a generic type.
• Add a Character_Set_Type etc. to a private tagged
  type.
• Add a Modified version of all of the methods in
  Ada.Strings.Wide_Bounded
• Instantiate (Character_Set gt Utf16)

13
XForms 1.0W3C Recommendation 14 October 2003

• XForms model, instance data, and user interface
• Separates presentation from content
• Benefits reuse, strong typing, reduction of
  round-trips to the server, device independence,
  and a reduces the need for scripting.
• XForms
• Not a free-standing document type
• Integrated into XHTML or SVG.
• Examples from http//www.formsplayer.com/

14
Ada GUI based on SVG XForms

• Could be based on either CLAW or GNAVI
• Need thick binding for operating system
  independence
• Standard Ada implementation based on SVG
  data-types produces output to be executed by
  operating system
• or
• outputs SVG
• XForms can primarily be an SVG application

15
SOAP

• Interface SOAP with the Ada Distributed Systems
  Annex
• And/or
• CORBA replace IDL with XML?

16
Odds Ends

• A complete description of Ada in XML schema would
  permit the use of an XML based word processor as
  a program editor.
• The design documentation and the source could be
  connected by hypertext links.
• To begin this,I Translated Thomas
  WolfsAdaBrowse Document Type Definition (DTD)
  into a Schema.

17
Conclusions Bottom Line

• Make the Ada and XML schema data-types the same.
• Treat the XML presentation tools as a new very
  important API for a user interface standard.
• Base new Ada API designs on XML standards.
• Combine SOAP with the Ada Distributed Systems
  Annex and/or CORBA