Groovy is an object-oriented scripting language for the Java Virtual Machine (JVM) that can be optionally statically typed. It aims to provide features like dynamic typing, closures, builders and other conveniences while retaining compatibility with Java. Groovy code compiles to Java bytecode and passes through several phases including parsing, semantic analysis, instruction selection and class generation. It has a large ecosystem and is designed to integrate well with Java while allowing programming in a more concise, less boilerplate-oriented style.

1. COMO VOCÊ NUNCA VIU

2. /DEV/FELIPEMAMUD

3. Disclaimer

4. It's Groovy
● Groovy is object-oriented dynamic language by default, but…
… can be optionally typed;
… can be static type checking with @TypeChecked;
● dynamic != interpreted;
● static compilation with @CompileStatic;
● Groovy compiles down to JVM bytecode;
● Script vs Classes;

5. A little bit of history
2003 2007 2008
1.0
2011 2012
2.0
2014 20152005

6. Compilation phases
1. Initialization (read source files and config compiler)
2. Parsing (text → concrete syntax tree; Antlr2)
3. Conversion (CST → AST) @Grab
4. Semantic Analysis (resolve classes, consistency and grammar) @Lazy @Builder @Field @Log
5. Canonicalization (AST finalize and last chance to use AST) @Delegate @ToString @Immutable
6. Instruction Selection (instruction set for bytecode / type checking) @CompileStatic @TypeChecked
7. Class Generation (create bytecode in memory, AST → bytecode)
8. Output (binary output .class to file system)
9. Finalization (perform cleanup tasks, unused today!)

7. Awesome!
● Optional (Typing, Semicolons, Parentheses, public & return keyword);
● Native syntax constructs (Closures, Lists, Maps, Regex, Ranges)
● Boilerplate mode off; (String, BigDecimal, Null, Truth, Switch)
● Java Interoperability & integration;
● Groovy Development Kit enhancements (GDK);
● DSL easy mode on;
● Builders;
● AST Transformations;

8. Groovy’s nature
programming language…
as type safe as you want it
static type checking
as fast as you need
static compilation
as functional as you make it
closures, immutable, etc…

9. Ecosystem

10. References
● Groovy documentation
http://groovy-lang.org/documentation.html
● Guillaume Laforge's Blog
http://glaforge.appspot.com
● Cédric Champeau's Blog
http://melix.github.io/blog
● Groovy in Action, 2nd Edition
https://www.manning.com/books/groovy-in-action-second-edition

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12. Felipe Mamud
@ftmamud
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