# pt_introduction(3tcl) 1 pt "Parser Tools"

## Name

pt_introduction - Introduction to Parser Tools

## Synopsis

- package require Tcl 8.5

## Description

Welcome to the Parser Tools, a system for the creation and manipulation of parsers and the grammars driving them.

What are your goals which drove you here ?

1. Do you simply wish to create a parser for some language ?

   In that case have a look at our parser generator application, pt, or, for a slightly deeper access, the package underneath it, pt::pgen.

2. Do you wish to know more about the architecture of the system ?

   This is described in the section Parser Tools Architecture, below

3. Is your interest in the theoretical background upon which the packages and tools are build ?

   See the Introduction to Parsing Expression Grammars.

## Parser Tools Architecture

The system can be split into roughly three layers, as seen in the figure below

Image: architecture

These layers are, from high to low:

1. At the top we have the application and the packages using the packages of the layer below to implement common usecases. One example is the aforementioned pt::pgen which provides a parser generator.

   The list of packages belonging to this layer can be found in section User Packages

2. In this layer we have the packages which provide the core of the functionality for the whole system. They are, in essence, a set of blocks which can be combined in myriad ways, like Lego (tm). The packages in the previous level are 'just' pre-fabricated combinations to cover the most important use cases.

   The list of packages belonging to this layer can be found in section Core Packages

3. Last, but not least is the layer containing support packages providing generic functionality which not necessarily belong into the module.

   The list of packages belonging to this layer can be found in section Support Packages

### User Packages

pt::pgen

### Core Packages

This layer is further split into six sections handling the storage, import, export, transformation, and execution of grammars, plus grammar specific support packages.

Storage
  pt::peg::container
Export
  pt::peg::export
  pt::peg::export::container
  pt::peg::export::json
  pt::peg::export::peg
  pt::peg::to::container
  pt::peg::to::json
  pt::peg::to::peg
  pt::peg::to::param
  pt::peg::to::tclparam
  pt::peg::to::cparam
Import
  pt::peg::import
  pt::peg::import::container
  pt::peg::import::json
  pt::peg::import::peg
  pt::peg::from::container
  pt::peg::from::json
  pt::peg::from::peg
Transformation
Execution
  pt::peg::interp
  pt::rde
Support
  pt::tclparam::configuration::snit
  pt::tclparam::configuration::tcloo
  pt::cparam::configuration::critcl
  pt::ast
  pt::pe
  pt::peg

### Support Packages

pt::peg::container::peg
text::write
configuration
paths
char

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category pt of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide unified diffs, i.e the output of diff -u.

Note further that attachments are strongly preferred over inlined patches. Attachments can be made by going to the Edit form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

## Keywords

EBNF, LL(k), PEG, TDPL, context-free languages, expression, grammar, matching, parser, parsing expression, parsing expression grammar, push down automaton, recursive descent, state, top-down parsing languages, transducer

## Category

Parsing and Grammars

## Copyright

Copyright © 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>