Parse tree design

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A context free grammar defines a language, e.g.

Grammar.gif

A parse tree shows how a sentence in the language is structured according to the grammar.

Parsetree.gif

Contents

Terminology

In parsing lingo a symbol is a name in a grammar. Each symbol is either a terminal or a non-terminal. Non-terminals appear on the left hand side of a grammar production; terminals don't.

Issues Discussed

Around this design we constructed a variety of patterns and discussed them.

Patterns in Use

  • DTSTTCPW Design

Standard Composite Solution

Parse-tree-sol-basic-composite.png

Wal's Solution

Parse-tree-sol-wals.png

Wal's Solution Refactored

Parse-tree-sol-wals-refactored.png

Downcasting vs No-ops vs DBC based superclasses

Data Redundancy

Test Driven Development & Refactoring

See Also

Personal tools