Tree Description Language (TreeDL) is a

computer language A computer language is a formal language used to communicate with a computer. Types of computer languages include: * Construction language – all forms of communication by which a human can specify an executable problem solution to a compu ...

for description of strictly-typed tree data structures and operations on them. The main use of TreeDL is in the development of language-oriented tools (

compiler In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...

s, translators, etc.) for the description of a structure of

abstract syntax tree In computer science, an abstract syntax tree (AST), or just syntax tree, is a tree representation of the abstract syntactic structure of text (often source code) written in a formal language. Each node of the tree denotes a construct occurring ...

s. Tree description can be used as * a documentation of interface between

parser Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term ''parsing'' comes from Lati ...

and other subsystems; * a source for generation of data types representing a tree in target programming languages; * a source for generation of various support code:

visitor A visitor, in English and Welsh law and history, is an overseer of an autonomous ecclesiastical or eleemosynary institution, often a charitable institution set up for the perpetual distribution of the founder's alms and bounty, who can interve ...

s, walkers,

factories A factory, manufacturing plant or a production plant is an industrial facility, often a complex consisting of several buildings filled with machinery, where workers manufacture items or operate machines which process each item into another. T ...

, etc. TreeDL can be used with any

parser generator In computer science, a compiler-compiler or compiler generator is a programming tool that creates a parser, interpreter, or compiler from some form of formal description of a programming language and machine. The most common type of compiler- ...

that allows custom actions during parsing (for example,

ANTLR In computer-based language recognition, ANTLR (pronounced ''antler''), or ANother Tool for Language Recognition, is a parser generator that uses LL(*) for parsing. ANTLR is the successor to the Purdue Compiler Construction Tool Set (PCCTS), firs ...

JavaCC JavaCC (Java Compiler Compiler) is an open-source parser generator and lexical analyzer generator written in the Java programming language. JavaCC is similar to yacc in that it generates a parser from a formal grammar written in EBNF notation. U ...

Language overview

Tree description lists the node types allowed in a tree. Node types support

single inheritance Multiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class. It is distinct from single inheritance, where an object or ...

. Node types have children and attributes. Children must be of defined node type. Attributes may be of primitive type (numeric, string, boolean), enum type or node type. Attributes are used to store literals during tree construction and additional information gathered during tree analysis (for example, links between reference and definition, to represent

higher-order abstract syntax In computer science, higher-order abstract syntax (abbreviated HOAS) is a technique for the representation of abstract syntax trees for languages with variable binders. Relation to first-order abstract syntax An abstract syntax is ''abstract'' be ...

). Operations over a tree are defined as

multimethod Multiple dispatch or multimethods is a feature of some programming languages in which a function or method can be dynamically dispatched based on the run-time (dynamic) type or, in the more general case, some other attribute of more than one of ...

s. Advantages of this approach are described in the articl
Treecc: An Aspect-Oriented Approach to Writing Compilers
Tree descriptions support inheritance to allow modularity and reuse of base language tree descriptions for language extensions.

External links

*
old TreeDL home
* {{webarchive , url=https://web.archive.org/web/20070703044959/http://www.southern-storm.com.au/treecc.html , date=July 3, 2007 , title=treecc Programming languages Domain-specific knowledge representation languages

Language overview

See also

External links