ANTLR4 in depth
If you can't read please download the document
-
Upload
- -
Category
Engineering
-
view
647 -
download
2
Transcript of ANTLR4 in depth
Vladimir Kozhaev
Freelancer
Development of programming languages and development tools.
If you need to develop a domain specific language, IDE based on Eclipse or Inellij Idea, parser, compiler do not heistate to ask me.
email:[email protected], skype:vladimir.kozhaev blog:http://gamesdevandmath.blogspot.com
ANTLR 4, DSL development in depth
ANTLR overview
ANTLR (ANother Tool for Language Recognition) is a powerful parser generator for reading, processing, executing, or translating structured text or binary files. It's widely used to build languages, tools, and frameworks. From a grammar, ANTLR generates a parser that can build and walk parse trees.
Now avaiable version 4.5.3
Java, C#, JavaScript, Python2, Python3 targets
Some alternatives:JFlex,JLex,CookCC,AustenX
Why ANTLR?
Developed with java
Actively developing project
Opensource
Vide range of the tools and target languages
Existing community
Good book: The Definitive ANTLR 4 Reference by Terence Parr
A lot of the syntax sugar:left recursion, right associativity etc
What is ANTLR
Parsers(for example log files)
Translators(from JSON to XML, pseudocode to Java)
Domain Specific Languages(DSL)
What is ANTLR
What is ANTLR
What Is ANTLR
ANTLR patterns
Lexems vs Fragments where is a difference?
A fragment will never be counted as a token, it only serves to simplify a grammar.
They need to be referenced from a lexer rule
Matching a NUMBER will always return a NUMBER to the lexer, regardless of if it matched "1234", "0xab12", or "0777"
Priority Rules
Several lexer rules can match the same input text. In that case, the token type will be chosen as follows:First, select the lexer rule which matches the longest input
If several lexer rules match the same input length, choose the first one, based on definition order
Error recovery strategies
Error recovering
Visitors,Listeners,Actions
Example 1, with visitor
Example 2, with listener
Example 3, with embeded action
See https://github.com/vladimirkozhaev/https---github.com-vladimirkozhaev-calc_antlr
Lexer vs parser rules
Lexer vs parser, question two steps with the same sence
Lexer rules are used to split text on the tokens
Parser rules - for higher level parsing
Right associativity
expr : expr '^' expr // ^ operator is right associative| INT;
Eclipse ANTLR IDE
Eclipse ANTLR IDE
Questions
Ask me please?
