Crystallabs-helpers

Collection of useful helper modules.

There is no disadvantage to using this shard in projects that only require part of its functionality. Crystal does not include unused functions in the resulting binary.

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     crystallabs-helpers:
       github: crystallabs/crystallabs-helpers.cr
       version: ~> 1.0
   

2. Run shards install

Usage

Helper functionality is split by modules. Include the modules where you need them:

Crystallabs::Helpers::Logging

    macro included
      Log = ::Log.for self.name.gsub("::", '.').underscore
    end

    # Returns as a string the current method name and all arguments inspected.
    macro my(*args, line=__LINE__)
    end

Usage:

  # Automatically prefixes log lines with self' name
  Log.debug { ... }

  # Log object/variable values inspected
  Log.debug { my varx, vary, ... }

Crystallabs::Helpers::Boolean

    def to_b(arg : String, empty = false)
    def to_b(arg : Int, empty = false)
    def to_b(arg : Char, empty = false)
    def to_b(arg : Nil, empty = false)
    def to_b(arg : Bool)

    def to_i(arg : Bool)

Usage:

  to_b "0"
  to_b 1
  to_b '0'
  to_b nil

  to_i true

Crystallabs::Helpers::Enums

Lets callers refer to enum members by Symbol or String shorthand (e.g. :center / "center", or {:vcenter, :right} for @[Flags] enums) instead of spelling out the fully-qualified enum constant.

    # Generic conversion, works for any enum T:
    Crystallabs::Helpers::Enums.from(T.class, value)

    # Declares an enum property whose setter also accepts shorthands:
    macro enum_property(decl)

Usage:

  Crystallabs::Helpers::Enums.from AlignFlag, :center            # => Center
  Crystallabs::Helpers::Enums.from AlignFlag, "center"           # => Center
  Crystallabs::Helpers::Enums.from AlignFlag, {:vcenter, :right} # => VCenter | Right

  class Widget
    Crystallabs::Helpers::Enums.enum_property align : AlignFlag = AlignFlag::Top
  end

  w = Widget.new
  w.align = :center            # => Center
  w.align = {:vcenter, :right} # => VCenter | Right
  w.align = AlignFlag::Left    # real enum values still work

Crystallabs::Helpers::Alias_Methods

Allows aliasing methods. Use only when needed since in general Crystal ecosystem does not prefer aliases.

    macro alias_method(new_method, old_method)
    macro alias_previous(*new_methods)

Usage:

  alias_method new_method_name, existing_method_name
  alias_method :new_method_name=, :existing_method_name=

  def mymethod
  end
  alias_previous new_name