# pt::util(3tcl) 1.2 pt "Parser Tools"

## Name

pt::util - General utilities

## Synopsis

- package require Tcl 8.5 9
- package require pt::ast ?1.2?

- ::pt::util error2readable error text
- ::pt::util error2position error text
- ::pt::util error2text error

## Description

Are you lost ? Do you have trouble understanding this document ? In that case please read the overview provided by the Introduction to Parser Tools. This document is the entrypoint to the whole system the current package is a part of.

This package provides general utility commands.

This is a supporting package in the Core Layer of Parser Tools.

Image: arch_core_support

## API

::pt::util error2readable error text

  This command takes the structured form of a syntax error as thrown by parser runtimes and the input text to the parser which caused that error and returns a string describing the error in a human-readable form.

  The input text is required to convert the character position of the error into a more readable line/column format, and to provide excerpts of the input around the error position.

::pt::util error2position error text

  This command takes the structured form of a syntax error as thrown by parser runtimes and the input text to the parser which caused that error and returns a 2-element list containing the line number and column index for the error's character position in the input, in this order.

::pt::util error2text error

  This command takes the structured form of a syntax error as thrown by parser runtimes and returns a list of strings, each describing a possible expected input in a human-readable form.

## 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>