XML

1
XML eXtensible Markup Language

• Similar to HTML in some ways
• mark-up language
• Mixture of commands and data
• HTML markup for formatting
• XML markup for data description
• Used in lots of different ways
• Self-describing data
• Intermediate parser output
• XSL eXtensible Stylesheet Language
• Provides formatting rules for XML
• Internet Explorer 5 (IE5)

2
655 Project Syntax

• ltprogramgt ltstatementgt
• ltstatementgt ltassignmentgt ltconditionalgt
  ltloopgt
• ltassignmentgt ltidentifiergt ltexprgt
• ltconditionalgt if ( ltexprgt ) then
  ltstatementgt if ( ltexprgt ) then
  ltstatementgt
  else ltstatementgt
• ltloopgt while ( ltexprgt ) do ltstatementgt
• lttermgt ltidentifiergt ltnumbergt ( ltexprgt )
• ltexprgt lttermgt lttermgt ltoperatorgt ltexprgt

3
XML DTD Part-1

• lt?xml version"1.0" encoding"ISO-8859-1" ?gt
• lt!ELEMENT program (l-brace, statement, r-brace)gt
• lt!ELEMENT statement (assignment conditional
  loop)gt
• lt!ELEMENT assignment (identifier, assign-opr,
  expression, semicolon)gt
• lt!ELEMENT conditional (if, l-paren, expression,
  r-paren, then, l-brace, statement, r-brace)gt
• lt!-- how to add else clause --gt
• lt!ELEMENT loop (while, l-paren, expression,
  r-paren, do, l-brace, statement, r-brace)gt
• lt!ELEMENT expression (term (term, operator,
  expression))gt
• lt!ELEMENT term (identifier number (l-paren,
  expression, r-paren))gt

4
DTD Part-2

• lt!ELEMENT identifier (PCDATA)gt
• lt!ELEMENT number (PCDATA)gt
• lt!ELEMENT l-brace EMPTYgt
• lt!ELEMENT r-brace EMPTYgt
• lt!ELEMENT assign-opr EMPTYgt
• lt!ELEMENT semicolon EMPTYgt
• lt!ELEMENT l-paren EMPTYgt
• lt!ELEMENT r-paren EMPTYgt
• lt!ELEMENT if EMPTYgt
• lt!ELEMENT then EMPTYgt
• lt!ELEMENT while EMPTYgt
• lt!ELEMENT do EMPTYgt
• lt!ELEMENT operator EMPTYgt
• lt!ATTLIST operator which (plus minus times
  divide) "plus"gt

5
XML Version of a Program

• lt?xml version"1.0" encoding"ISO-8859-1"
  ?gtlt!DOCTYPE program SYSTEM "syntax-a.dtd"gtlt?xml-
  stylesheet type"text/xsl" href"syntax-a.xsl"?gtlt
  PROGRAMgt ltL-BRACE/gt ltSTATEMENTgt ltASSIGNMENTgt
  ltIDENTIFIERgtleftlt/IDENTIFIERgt ltASSIGN-OPR
  /gt ltEXPRESSIONgtltTERMgt ltIDENTIFIERgtrightlt/IDEN
  TIFIERgt lt/TERMgtlt/EXPRESSIONgt ltSEMICOLON
  /gt lt/ASSIGNMENTgt lt/STATEMENTgt ltR-BRACE
  /gtlt/PROGRAMgt

6
XSL-1

• lt?xml version"1.0"?gt
• ltxslstylesheet version"1.0 xmlnsxsl"http//ww
  w.w3.org/TR/WD-xsl"gt
• ltxsltemplate match"/"gt
• lthtmlgtltheadgt lttitlegtCIS 655 Example
  XMLlt/titlegtlt/headgtltbodygt ltxslapply-templates
  select"PROGRAM"/gt lt/bodygtlt/htmlgt
• lt/xsltemplategt
• ltxsltemplate match"PROGRAM"gtltxslapply-templates
  /gtlt/xsltemplategt
• ltxsltemplate match"STATEMENT"gt
  ltxslapply-templates /gt lt/xsltemplategt
• ltxsltemplate match"ASSIGNMENT"gt
  ltxslapply-templates /gt lt/xsltemplategt
• ltxsltemplate match"EXPRESSION"gt
  ltxslapply-templates /gt lt/xsltemplategt
• ltxsltemplate match"TERM"gt ltxslapply-templates
  /gt lt/xsltemplategt

7
XSL-2

• ltxsltemplate match"IDENTIFIER"gt ltfont
  color"red"gtltxslvalue-of select"."
  /gtlt/fontgtlt/xsltemplategt
• ltxsltemplate match"NUMBER"gt ltxslvalue-of
  select"." /gt lt/xsltemplategt
• ltxsltemplate match"L-BRACE"gt ltbgtL-BRACE ltbr
  /gtlt/bgt lt/xsltemplategt
• ltxsltemplate match"R-BRACE"gt ltbr
  /gtltbgtR-BRACElt/bgt lt/xsltemplategt
• ltxsltemplate match"ASSIGN-OPR"gt
  ltbgtASSIGN-OPRlt/bgt lt/xsltemplategt
• ltxsltemplate match"SEMICOLON"gt ltbgtSEMICOLONlt/bgt
  lt/xsltemplategt
• ltxsltemplate match"OPERATOR"gt ltxslvalue-of
  select"_at_WHICH" /gt lt/xsltemplategt
• lt/xslstylesheetgt

8
XML Example

• Instructors little example
• proj-syntax.xml
• proj-syntax.dtd
• proj-syntax.xsl
• Potential use in conjunction with 655 project
• Define syntax for language youre building
• Write sample programs in your language
• Write a parser for your language
• Parse your examples to make syntax trees
• Output those syntax trees in XML
• XSL style sheets to display those parse trees