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Crystal

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Manuals

Crystal

GitHub

Welcome
Specification
Specification
- About this guide
- The Program
- Comments
- Documenting code
- Literals
  Literals
  - Nil
  - Bool
  - Integers
  - Floats
  - Char
  - String
  - Symbol
  - Array
  - Hash
  - Range
  - Regex
  - Tuple
  - NamedTuple
  - Proc
  - Command
- Assignment
- Local variables
- Control expressions
  Control expressions
  - Truthy and falsey values
  - if
    
    if
    
    As a suffix
    
    As an expression
    
    Ternary if
    
    if var
    
    if var.is_a?(...)
    
    if var.responds_to?(...)
    
    if var.nil?
    
    if !
  - unless
  - case
  - select
  - while
    
    while
    
    break
    
    next
  - until
  - &&
  - ||
- Requiring files
- Types and methods
  Types and methods
  - Everything is an object
  - Classes and methods
    
    Classes and methods
    
    new, initialize and allocate
    
    Methods and instance variables
    
    Type inference
    
    Union types
    
    Overloading
    
    Default parameter values and named arguments
    
    Splats and tuples
    
    Type restrictions
    
    Return types
    
    Method arguments
    
    Operators
    
    Visibility
    
    Inheritance
    
    Inheritance
    
    Virtual and abstract types
    
    Class methods
    
    Class variables
    
    finalize
  - Modules
  - Generics
  - Structs
  - Constants
  - Enums
  - Blocks and Procs
    
    Blocks and Procs
    
    Capturing blocks
    
    Proc literal
    
    Block forwarding
    
    Closures
  - alias
- Exception handling
- Type grammar
- Type reflection
  Type reflection
  - is_a?
  - nil?
  - responds_to?
  - as
  - as?
  - typeof
- Type autocasting
- Macros
  Macros
- Annotations
  Annotations
  - Built-in annotations
- Low-level primitives
  Low-level primitives
- Compile-time flags
  Compile-time flags
  - Cross-compilation
  - Platform Support
- C bindings
  C bindings
  - lib
  - fun
    
    fun
    
    out
    
    to_unsafe
  - struct
  - union
  - enum
  - Variables
  - Constants
  - type
  - alias
  - Callbacks
- Unsafe code
Guides
Guides
- Performance
- Concurrency
- Testing
- Writing Shards
  Writing Shards
  - Hosting on GitHub
  - Hosting on GitLab
- Continuous Integration
  Continuous Integration
  - GitHub Actions
  - CircleCI
- Static Linking
- Crystal for Rubyists
  Crystal for Rubyists
  - Metaprogramming Help
- Database
  Database
- Coding style
Tutorials
Tutorials
- Getting started
  Getting started
  - An HTTP Server
  - A Command Line Application
- Language introduction
  Language introduction
  - Hello World
  - Variables
  - Math
  - Strings
  - Control Flow
  - Methods
Manuals
Manuals

Manuals¶

Technical details about commands and tools of Crystal.

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