ruby on rails 5 lambda语法错误，意外=>，期望'）'

Question

I have a migration file create_subject (code of which is below), a Subject class contains scopes using lambda syntax. When I call Subject.visible , I get syntax errors.

class CreateSubjects < ActiveRecord::Migration[5.0]
  def up
    create_table :subjects do |t|
      t.string "name"
      t.integer "position"
      t.boolean "visible", :default=>false

      t.timestamps
    end
  end

  def down
    drop_table :subjects
  end
end

This is my Subject class

Console error log

irb(main):003:0> Subject.visible
SyntaxError: C:/Users/SS/Sites/simple_cms/app/models/subject.rb:3: syntax error, unexpected =>, expecting ')'
scope :visible, -> { where (:visible => true) }
                                   ^
C:/Users/SS/Sites/simple_cms/app/models/subject.rb:4: syntax error, unexpected =>, expecting ')'
scope :invisible, -> { where (:visible => false) }
                                     ^
C:/Users/SS/Sites/simple_cms/app/models/subject.rb:7: syntax error, unexpected '|'
scope :search, -> {|query| where (["name LIKE ?", "%#{query}%"]) }
                ^
C:/Users/SS/Sites/simple_cms/app/models/subject.rb:7: syntax error, unexpected ( arg, expecting keyword_do or '{' or '('
scope :search, -> {|query| where (["name LIKE ?", "%#{query}%"]) }

Answer 1

Do not put space before opening parenthesis when calling methods. It should be like this

class Subject < ApplicationRecord
  scope :visible, -> { where(:visible => true) }
  scope :invisible, -> { where(:visible => false) }
  scope :sorted, -> { order("position ASC") }
  scope :search, ->(query) { where(["name LIKE ?", "%#{query}%"]) }
  # and so on ...
end

Answer 2

If you are going to put query in pipes |query| then use:

scope :search,lambda{|query| where(["name LIKE ?", "%#{query}%"]) }

instead of

scope :search, ->(query) { where(["name LIKE ?", "%#{query}%"]) }