antlr/doc/faq/index.md

# Frequently-Asked Questions (FAQ)

This is the main landing page for the ANTLR 4 FAQ. The links below will take you to the appropriate file containing all answers for that subcategory.

*To add to or improve this FAQ, [fork](https://help.github.com/articles/fork-a-repo/) the [antlr/antlr4 repo](https://github.com/antlr/antlr4) then update this `doc/faq/index.md` or file(s) in that directory.  Submit a [pull request](https://help.github.com/articles/creating-a-pull-request/) to get your changes incorporated into the main repository. Do not mix code and FAQ updates in the sample pull request.* **You must sign the contributors.txt certificate of origin with your pull request if you've not done so before.**

## Getting Started

* [How to I install and run a simple grammar?](getting-started.md)
* [Why does my parser test program hang?](getting-started.md)

## Installation

* [Why can't ANTLR (grun) find my lexer or parser?](installation.md)
* [Why can't I run the ANTLR tool?](installation.md)
* [Why doesn't my parser compile?](installation.md)

## General

* [Why do we need ANTLR v4?](general.md)
* [What is the difference between ANTLR 3 and 4?](general.md)
* [Why is my expression parser slow?](general.md)

## Grammar syntax

## Lexical analysis

* [How can I parse non-ASCII text and use characters in token rules?](lexical.md)
* [How do I replace escape characters in string tokens?](lexical.md)
* [Why are my keywords treated as identifiers?](lexical.md)
* [Why are there no whitespace tokens in the token stream?](lexical.md)

## Parse Trees

* [How do I get the input text for a parse-tree subtree?](parse-trees.md)
* [What if I need ASTs not parse trees for a compiler, for example?](parse-trees.md)
* [When do I use listener/visitor vs XPath vs Tree pattern matching?](parse-trees.md)

## Translation

* [ASTs vs parse trees](parse-trees.md)
* [Decoupling input walking from output generation](parse-trees.md)

## Actions and semantic predicates

* [How do I test if an optional rule was matched?](actions-preds.md)

## Error handling

* [How do I perform semantic checking with ANTLR?](error-handling.md)
adding a few sample faq files 2015-10-26 06:09:29 +08:00			`# Frequently-Asked Questions (FAQ)`
add index of faq 2015-10-26 05:04:14 +08:00
finish adding the faq 2015-10-28 01:44:23 +08:00			`This is the main landing page for the ANTLR 4 FAQ. The links below will take you to the appropriate file containing all answers for that subcategory.`

first doc commit 2015-10-28 08:36:22 +08:00			To add to or improve this FAQ, [fork](https://help.github.com/articles/fork-a-repo/) the [antlr/antlr4 repo](https://github.com/antlr/antlr4) then update this `doc/faq/index.md` or file(s) in that directory. Submit a [pull request](https://help.github.com/articles/creating-a-pull-request/) to get your changes incorporated into the main repository. Do not mix code and FAQ updates in the sample pull request. You must sign the contributors.txt certificate of origin with your pull request if you've not done so before.
finish adding the faq 2015-10-28 01:44:23 +08:00
add index of faq 2015-10-26 05:04:14 +08:00			`## Getting Started`

adding a few sample faq files 2015-10-26 06:09:29 +08:00			`* [How to I install and run a simple grammar?](getting-started.md)`
			`* [Why does my parser test program hang?](getting-started.md)`
add index of faq 2015-10-26 05:04:14 +08:00
			`## Installation`

adding a few sample faq files 2015-10-26 06:23:01 +08:00			`* [Why can't ANTLR (grun) find my lexer or parser?](installation.md)`
			`* [Why can't I run the ANTLR tool?](installation.md)`
			`* [Why doesn't my parser compile?](installation.md)`
add index of faq 2015-10-26 05:04:14 +08:00
			`## General`

adding a few sample faq files 2015-10-26 06:23:01 +08:00			`* [Why do we need ANTLR v4?](general.md)`
			`* [What is the difference between ANTLR 3 and 4?](general.md)`
			`* [Why is my expression parser slow?](general.md)`
add index of faq 2015-10-26 05:04:14 +08:00
			`## Grammar syntax`

			`## Lexical analysis`

adding more faq 2015-10-26 06:32:37 +08:00			`* [How can I parse non-ASCII text and use characters in token rules?](lexical.md)`
			`* [How do I replace escape characters in string tokens?](lexical.md)`
			`* [Why are my keywords treated as identifiers?](lexical.md)`
			`* [Why are there no whitespace tokens in the token stream?](lexical.md)`
add index of faq 2015-10-26 05:04:14 +08:00
			`## Parse Trees`

finish adding the faq 2015-10-28 01:44:23 +08:00			`* [How do I get the input text for a parse-tree subtree?](parse-trees.md)`
			`* [What if I need ASTs not parse trees for a compiler, for example?](parse-trees.md)`
			`* [When do I use listener/visitor vs XPath vs Tree pattern matching?](parse-trees.md)`
add index of faq 2015-10-26 05:04:14 +08:00
			`## Translation`

finish adding the faq 2015-10-28 01:44:23 +08:00			`* [ASTs vs parse trees](parse-trees.md)`
			`* [Decoupling input walking from output generation](parse-trees.md)`
add index of faq 2015-10-26 05:04:14 +08:00
			`## Actions and semantic predicates`

finish adding the faq 2015-10-28 01:44:23 +08:00			`* [How do I test if an optional rule was matched?](actions-preds.md)`
add index of faq 2015-10-26 05:04:14 +08:00
			`## Error handling`

finish adding the faq 2015-10-28 01:44:23 +08:00			`* [How do I perform semantic checking with ANTLR?](error-handling.md)`