Implementation of a XML 1.0-parser using pest.

⛳ Roadmap

1. Syntax Parser

• write the grammar file(s)

  • Test: ExternalID (everything under ###External Entities+Expl in #XML Overview)

• add data structures

• (add methods for manipulating data structures & writing the data back )

🎓 Personal Learnings

• Markup- and Programming-Languages are just a sequence of strings/bytes in the end
• Specification != Implementation is possible
• writing Grammar-Rules in PEG
• Unicode-Encoding

XML Overview

->see XML 1.0 Spec: Character Data and Markup

Markup = Define document's structure (or contain metadata)

• STag(start-tag),ETag(end-tag),EmptyElemTag
• EntityRef,CharRef
• Comment
• CDStart,CDEnd
• doctypedecl (DTD)
• PIs (Processing Instructions)
• XMLDecl (EncodingDecl,VersionInfo,SDDecl:standalone decl)
• TextDecl (for external parsed entities)

Character Data = document's content

• CDATA = for escaping blocks of texts containing markup-strings

Entities

=storage units

• Document Entity = starting point for XML processor; contained in every XML document
• Parsed Entity = contents="replacement text"
• Unparsed Entity = may (or may not) be text and if text may be other than XML (eg gif)
  • ->no restrictions on contents of unparsed entities!
• Parameter Entities = for use within DTD

External Entities

System Identifier (SystemLiteral) = mostly a URI reference

• no fragment identifier (#) within URI!!
• relative URI = relative to XML-doc in which this External Entity is defined?? (unsure, see Spec 4.2.2)

Example

<!ENTITY open-hatch
         SYSTEM "http://www.textuality.com/boilerplate/OpenHatch.xml">
<!ENTITY open-hatch
         PUBLIC "-//Textuality//TEXT Standard open-hatch boilerplate//EN"
         "http://www.textuality.com/boilerplate/OpenHatch.xml">
<!ENTITY hatch-pic
         SYSTEM "../grafix/OpenHatch.gif"
         NDATA gif >

• taken from 4.2.2 External Entities