Release 0.7.2

Fixes an extra `= NULL` appearing at times.

.rubocop.yml

@@ -0,0 +1,32 @@
+inherit_from: .rubocop_todo.yml
+
+Metrics/LineLength:
+    Enabled: false
+
+Metrics/ParameterLists:
+    Enabled: false
+
+Style/Documentation:
+    Enabled: false
+
+Style/ClassAndModuleChildren:
+    Enabled: false
+
+Metrics/ModuleLength:
+    Enabled: false
+
+Style/TrailingCommaInLiteral:
+    EnforcedStyleForMultiline: comma
+
+Style/TrailingCommaInArguments:
+    EnforcedStyleForMultiline: comma
+
+Style/NestedParenthesizedCalls:
+    Enabled: false
+
+Style/BracesAroundHashParameters:
+  Exclude:
+    - 'test/test_*.rb'
+
+Style/IndentArray:
+  EnforcedStyle: consistent

.rubocop_todo.yml

@@ -0,0 +1,15 @@
+# This configuration was generated by
+# `rubocop --auto-gen-config`
+# on 2017-02-28 19:06:39 +0100 using RuboCop version 0.47.1.
+# The point is for the user to remove these configuration records
+# one by one as the offenses are removed from the code base.
+# Note that changes in the inspected code, or installation of new
+# versions of RuboCop, may require this file to be generated again.
+
+# Offense count: 1
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles.
+# SupportedStyles: prefer_alias, prefer_alias_method
+Style/Alias:
+  Exclude:
+    - 'test/helper.rb'

Gemfile

@@ -6,3 +6,4 @@ gem 'minitest'
 gem 'pry'
 gem 'rake'
 gem 'rubocop'
+gem 'sqlite3'

Gemfile.lock

@@ -1,43 +0,0 @@
-PATH
-  remote: .
-  specs:
-    rebel (0.1.0)
-
-GEM
-  remote: https://rubygems.org/
-  specs:
-    ast (2.3.0)
-    coderay (1.1.1)
-    method_source (0.8.2)
-    minitest (5.10.1)
-    parser (2.4.0.0)
-      ast (~> 2.2)
-    powerpack (0.1.1)
-    pry (0.10.4)
-      coderay (~> 1.1.0)
-      method_source (~> 0.8.1)
-      slop (~> 3.4)
-    rainbow (2.2.1)
-    rake (12.0.0)
-    rubocop (0.47.1)
-      parser (>= 2.3.3.1, < 3.0)
-      powerpack (~> 0.1)
-      rainbow (>= 1.99.1, < 3.0)
-      ruby-progressbar (~> 1.7)
-      unicode-display_width (~> 1.0, >= 1.0.1)
-    ruby-progressbar (1.8.1)
-    slop (3.6.0)
-    unicode-display_width (1.1.3)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  minitest
-  pry
-  rake
-  rebel!
-  rubocop
-
-BUNDLED WITH
-   1.14.5

README.md

@@ -7,7 +7,7 @@ You've been fighting yet another abstraction...
 Aren't you fed up with object-relation magic?
 But wait, here comes a humongous migration.
 Is ActiveRecord making you sick?
-To hell with that monstrous ARel expression!
+To hell with that monstrous Arel expression!
 Tell the truth, you were just wishing
 That it was as simple as a here-string.
 But could it keep some Ruby notation
@@ -21,13 +21,11 @@ No bullshit
 No layers
 No wrappers
 No smarty-pants
-No weird stance
 No sexy
+No nonsense
 No AST
 No lazy loading
 No crazy mapping
-No pretense
-No nonsense
 
 What you write is what you get: readable and obvious
 What you write is what you meant: tasty and delicious
@@ -36,6 +34,314 @@ Wait, it doesn't execute!?
 Just use your fave client gem, isn't that cute?
 ```
 
+## Motivation
+
+There are many a time where you end up knowing exactly what SQL query you want,
+yet have to wrap your head around for the ORM to produce it, which is when the
+point of such a layer is entirely defeated. Concatenating and interpolating
+only goes so far.
+
+As ActiveRecord grows, a significant decision has been taken in the Rails team
+to turn Arel into a library purely internal to ActiveRecord: the whole of it is
+basically considered internal and private, and only ActiveRecord's public
+interface should be used. Unfortunately, some highly dynamic, complex queries
+simply cannot be built using ActiveRecord, and concatenating strings to build
+SQL fragments and clauses simply does not cut it.
+
+## Philosophy
+
+- It must be readable as being SQL
+- Yet it must be as much Ruby syntax and types as possible
+- It must be able to produce fragments for others to use
+- And somehow be composable enough
+- It must not rely on metaprogramming magic
+- Nor need monkeypatching core types
+
+## Design
+
+There are two goals to this library:
+
+- query building
+- query execution
+
+Query building is about assembling a string containing a partial or complete
+query that you will later pass on to be executed by an executor.
+
+Query execution is about writing a query that will be executed on the spot.
+
+There are also non-goals to this library:
+
+- be any sort of ORM
+- or any sort of abstraction layer
+- or any sort of query optimiser
+
+## Usage
+
+`Rebel::SQL` is a module that contains building and execution features, and
+output ANSI-style SQL.
+
+`Rebel::SQL()` is a function that produces a customised module enabling support
+for alternative dialects, and when passed a block, allows you to write things
+more literally.
+
+Ruby types are best-effort mapped to SQL entities in a simple, regular way:
+
+- Symbols map to quoted SQL names such as tables, columns, aliases.
+- Strings map to strings. Always. (Quote style can be configured).
+- Integers and floats map to, well, integers and floats.
+- Date, Time and DateTime map to their ISO 8601 string representation
+- Booleans map to their respective ANSI literals (unless overriden by
+  configuration).
+- `nil` maps to `NULL` and is expected to have the same "unknown" semantic
+
+Variable arguments are generally used. Hashes, depending on context, map to:
+
+- `=` equality or `IN` operators joined by `AND`
+- `=` assignment operator joined by commas
+
+## Examples
+
+### Query building
+
+```ruby
+require 'rebel'
+
+# Here's a typical query
+Rebel::SQL.select :id, from: :customers, where: { :first_name => 'John', :last_name => 'Doe' }
+=> SELECT "id" FROM "customers" WHERE "first_name" = 'John' AND "last_name" = 'Doe'
+
+# More args give more columns
+Rebel::SQL.select :first_name, :last_name, from: :customers, where: { :id => [1, 2, 3] }
+=> SELECT "first_name", "last_name" FROM "customers" WHERE "id" IN (1, 2, 3)
+
+# * is special-cased for names
+Rebel::SQL.select :*, from: :customers, where: { :id => [1, 2, 3] }
+=> SELECT * FROM "customers" WHERE "id" IN (1, 2, 3)
+
+# You can emit fragments to produce clauses
+puts Rebel::SQL.and_clause :id => [1, 2, 3], :country => 'GB'
+=> "id" IN (1, 2, 3) AND "country" = 'GB'
+Rebel::SQL.where? :id => [1, 2, 3], :country => 'GB'
+=> WHERE "id" IN (1, 2, 3) AND "country" = 'GB'
+
+# Here the question mark means where? swallows nil arguments: maybe it's a Maybe monad
+Rebel::SQL.where?(nil)
+=> nil
+
+# Let's emit join clauses
+Rebel::SQL.join(:contracts, on: :customer_id => :id)
+#=> JOIN "contracts" ON "customer_id" = "id"
+Rebel::SQL.join(:contracts).on(:customer_id => :id)
+#=> JOIN "contracts" ON "customer_id" = "id"
+
+# :contracts might have an :id too, so we can disambiguate those columns
+Rebel::SQL.join(:contracts).on(:'contracts.customer_id' => :'customers.id')
+#=> JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+
+# Other types of join are obviously available
+Rebel::SQL.inner_join(:contracts).on(:'contracts.customer_id' => :'customers.id')
+#=> INNER JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+Rebel::SQL.outer_join(:contracts).on(:'contracts.customer_id' => :'customers.id')
+#=> OUTER JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+Rebel::SQL.left_outer_join(:contracts).on(:'contracts.customer_id' => :'customers.id')
+#=> LEFT OUTER JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+Rebel::SQL.right_outer_join(:contracts).on(:'contracts.customer_id' => :'customers.id')
+#=> RIGHT OUTER JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+
+# The type of join can be split off. Again, note the question mark.
+Rebel::SQL.inner? Rebel::SQL.join(:contracts).on(:'contracts.customer_id' => :'customers.id')
+#=> INNER JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+Rebel::SQL.left? Rebel::SQL.outer_join(:contracts).on(:'contracts.customer_id' => :'customers.id')
+#=> LEFT OUTER JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+
+# And in a full query
+Rebel::SQL.select :'customers.id', :'contracts.id',
+                  from: :customers,
+                  where: { :first_name => 'John', :last_name => 'Doe' },
+                  inner: Rebel::SQL.join(:contracts).on(:'contracts.customer_id' => :'customers.id'),
+                  order: Rebel::SQL.by(:'customer.age').asc
+#=> SELECT "customers"."id", "contracts"."id"
+#   FROM "customers"
+#   INNER JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+#   WHERE "first_name" = 'John' AND "last_name" = 'Doe'
+#   ORDER BY "customer"."age" ASC
+
+# All those Rebel::SQL can get unwieldy, so let's reduce the noise
+Rebel::SQL() do
+  select :'customers.id', :'contracts.id',
+         from: :customers,
+         where: { :first_name => 'John', :last_name => 'Doe' },
+         inner: join(:contracts).on(:'contracts.customer_id' => :'customers.id'),
+         order: by(:'customer.age').asc
+end
+#=> SELECT "customers"."id", "contracts"."id"
+#   FROM "customers"
+#   INNER JOIN "contracts" ON "contracts"."customer_id" = "customers"."id"
+#   WHERE "first_name" = 'John' AND "last_name" = 'Doe'
+#   ORDER BY "customer"."age" ASC
+
+# Now, that function can be used to make things different
+Rebel::SQL.name(:foo)
+#=> "foo"
+Rebel::SQL(identifier_quote: '`').name(:foo)
+#=> `foo`
+Rebel::SQL.value(true)
+#=> TRUE
+Rebel::SQL(true_literal: '1').value(true)
+#=> 1
+Rebel::SQL(true_literal: '1') { select value(true) }
+#=> SELECT 1
+
+# While we're at it, let's call arbitrary functions
+Rebel::SQL() { select function('NOW') }
+#=> SELECT NOW()
+Rebel::SQL() { select function('LENGTH', "a string") }
+#=> SELECT LENGTH('a string')
+Rebel::SQL() { select function('COUNT', :id), from: :customers, where: { :age => 42 } }
+#=> SELECT COUNT("id") FROM "customers" WHERE "age" = 42
+Rebel::SQL() { select count(:id), from: :customers, where: { :age => 42 } }
+#=> SELECT COUNT("id") FROM "customers" WHERE "age" = 42
+
+# And throw in some aliases
+Rebel::SQL() { select function('LENGTH', "a string").as(:length) }
+#=> SELECT LENGTH('a string') AS "length"
+Rebel::SQL() { select name(:id).as(:customer_id), from: :customers }
+#=> SELECT "id" AS "customer_id" FROM "customers"
+Rebel::SQL() { select count(:id).as(:count), from: :customers, where: { :age => 42 } }
+#=> SELECT COUNT("id") FROM "customers" WHERE "age" = 42
+
+# While we're counting things, let's group results
+Rebel::SQL() { select count(:id).as(:count), :country, from: :customers, group: by(:country).having(count(:customer_id) => 5) }
+#=> SELECT COUNT("id") AS "count", "country" FROM "customers" GROUP BY "country" HAVING COUNT("customer_id") = 5
+
+# Passing a hash does a best effort to map Ruby to SQL
+Rebel::SQL() { select :id, from: :customers, where: { :age => 42 } }
+#=> SELECT "id" FROM "customers" WHERE "age" = 42
+Rebel::SQL() { select :id, from: :customers, where: { :age => [20, 21, 22] } }
+#=> SELECT "id" FROM "customers" WHERE "age" IN (20, 21, 22)
+Rebel::SQL() { select :id, from: :customers, where: { :age => nil } }
+#=> SELECT "id" FROM "customers" WHERE "age" IS NULL
+
+# Using operators ensures the expected SQL operator is used
+Rebel::SQL() { select :id, from: :customers, where: name(:age).eq(42) }
+#=> SELECT "id" FROM "customers" WHERE "age" = 42
+Rebel::SQL() { select :id, from: :customers, where: name(:age).eq(nil) }
+#=> SELECT "id" FROM "customers" WHERE "age" = NULL
+Rebel::SQL() { select :id, from: :customers, where: name(:age).ne(42) }
+#=> SELECT "id" FROM "customers" WHERE "age" != NULL
+Rebel::SQL() { select :id, from: :customers, where: name(:age).is(42) }
+#=> SELECT "id" FROM "customers" WHERE "age" IS 42
+Rebel::SQL() { select :id, from: :customers, where: name(:age).is(nil) }
+#=> SELECT "id" FROM "customers" WHERE "age" IS NULL
+Rebel::SQL() { select :id, from: :customers, where: name(:age).is_not(nil) }
+#=> SELECT "id" FROM "customers" WHERE "age" IS NOT NULL
+
+# Other operators are available
+Rebel::SQL() { select :id, from: :customers, where: name(:age).ge(42) }
+#=> SELECT "id" FROM "customers" WHERE "age" >= 42
+Rebel::SQL() { select :id, from: :customers, where: name(:age).in(21, 22, 23) }
+#=> SELECT "id" FROM "customers" WHERE "age" IN (21, 22, 23)
+Rebel::SQL() { select :id, from: :customers, where: name(:first_name).like("J%") }
+#=> SELECT "id" FROM "customers" WHERE "first_name" LIKE "J%"
+
+# Aliases to overload operators are available
+Rebel::SQL() { select :id, from: :customers, where: name(:age) == 42 }
+#=> SELECT "id" FROM "customers" WHERE "age" = 42
+Rebel::SQL() { select :id, from: :customers, where: name(:age) < 42 }
+#=> SELECT "id" FROM "customers" WHERE "age" < 42
+Rebel::SQL() { select :id, from: :customers, where: name(:age) >= 42 }
+#=> SELECT "id" FROM "customers" WHERE "age" >= 42
+Rebel::SQL() { select :id, from: :customers, where: name(:age) != 42 }
+#=> SELECT "id" FROM "customers" WHERE "age" != 42
+
+# Conditions can be combined
+Rebel::SQL() { select :id, from: :customers, where: name(:age).gt(42).or(name(:age).lt(21)) }
+#=> SELECT "id" FROM "customers" WHERE ("age" > 42 OR "age" < 21)
+Rebel::SQL() { select :id, from: :customers, where: (name(:age) < 42).and(name(:age) > 21) }
+#=> SELECT "id" FROM "customers" WHERE ("age" < 42 AND "age" > 21)
+
+# Binary-wise operators can be used to tie conditions
+# WARNING: Usefulness if this hack is still debated. It might be removed in the future.
+Rebel::SQL() { select :id, from: :customers, where: ((name(:age) > 42) | (name(:age) < 21)) }
+#=> SELECT "id" FROM "customers" WHERE ("age" > 42 OR "age" < 21)
+Rebel::SQL() { select :id, from: :customers, where: name(:age).lt(42) & (name(:age).gt(21)) }
+#=> SELECT "id" FROM "customers" WHERE ("age" < 42 AND "age" > 21)
+
+```
+
+### Query execution
+
+If you provide Rebel::SQL an environment within which a query executor is
+available, queries can be executed directly.
+
+```ruby
+class CreateTableCustomers
+  include Rebel::SQL
+
+  # provide a connection that responds to exec(query)
+  def conn
+    @conn ||= PG.connect( dbname: 'sales' )
+  end
+
+  # remember that SQL() returns a module!
+  include Rebel::SQL(true_literal: '1', false_literal: '0')
+
+  # alternatively, redefine the provided exec (which calls conn.exec)
+  def exec(query)
+    @db ||= SQLite3::Database.new "test.db"
+    @db.execute(query)
+  end
+
+  def up
+    create_table :customers, {
+        id:         'SERIAL',
+        name:       'VARCHAR(255)',
+        address:    'VARCHAR(255)',
+        city:       'VARCHAR(255)',
+        zip:        'VARCHAR(255)',
+        country:    'VARCHAR(255)',
+    }
+
+    insert_into :customers,
+                { name: 'Lewis Caroll', address: '1, Alice St.', city: 'Oxford', zip: '1865', country: 'Wonderland' },
+                { name: 'Neal Stephenson', address: '2, Hiro Blvd.', city: 'Los Angeles', zip: '1992', country: 'Metaverse' }
+
+    results = select :name, :country, from: :customers
+
+    update :customers, set: { city: 'FooTown' }, where: { zip: 1234 }
+
+    delete_from :customers, where: { zip: 1234 }
+
+    truncate :customers
+  end
+
+  def down
+    drop_table :customers
+  end
+end
+```
+
+## FAQ
+
+### X is missing/database specific, how do I write it?
+
+You can use `Rebel::SQL.raw("whatever")` and drop it in.
+
+### Why the weird syntax like `inner: join` instead of `inner_join`?
+
+This allows for a more uniform interface as well as not monkeypatching core types.
+
+### Can I write nonsensical SQL with this?
+
+Yes. Just as you can write nonsensical SQL in SQL.
+
+### Your query builder is not using an AST.
+
+That's not a question. You're welcome to implement one that does though, and if
+it leverages the visitor pattern, allocates a trajillion objects along the way
+and manages to produce invalid SQL in some corner cases, well congratulations
+for reimplementing Arel.
+
 ## License
 
 MIT

lib/rebel/sql.rb

@@ -1,4 +1,6 @@
-module Rebel::SQL
+require 'date'
+
+module Rebel::SQLQ
   attr_reader :conn
 
   def exec(query)
@@ -6,125 +8,247 @@ module Rebel::SQL
   end
 
   def create_table(table_name, desc)
-    exec(SQL.create_table(table_name, desc))
+    exec(Rebel::SQL.create_table(table_name, desc))
   end
 
-  def select(*fields, from: nil, where: nil, inner: nil, left: nil, right: nil)
-    exec(SQL.select(*fields,
+  def drop_table(table_name)
+    exec(Rebel::SQL.drop_table(table_name))
+  end
+
+  def select(*fields, distinct: nil, from: nil, where: nil, inner: nil, left: nil, right: nil, group: nil, order: nil, limit: nil, offset: nil)
+    exec(Rebel::SQL.select(*fields,
+                           distinct: distinct,
                            from: from,
                            where: where,
                            inner: inner,
                            left: left,
-                    right: right))
+                           right: right,
+                           group: group,
+                           order: order,
+                           limit: limit,
+                           offset: offset))
   end
 
   def insert_into(table_name, *rows)
-    exec(SQL.insert_into(table_name, *rows))
+    exec(Rebel::SQL.insert_into(table_name, *rows))
   end
 
   def update(table_name, set: nil, where: nil, inner: nil, left: nil, right: nil)
-    exec(SQL.update(table_name, set: set, where: where, inner: inner, left: left, right: right))
+    exec(Rebel::SQL.update(table_name, set: set, where: where, inner: inner, left: left, right: right))
   end
 
   def delete_from(table_name, where: nil, inner: nil, left: nil, right: nil)
-    exec(SQL.delete_from(table_name, where: where, inner: inner, left: left, right: right))
+    exec(Rebel::SQL.delete_from(table_name, where: where, inner: inner, left: left, right: right))
   end
 
   def truncate(table_name)
-    exec(SQL.truncate(table_name))
+    exec(Rebel::SQL.truncate(table_name))
   end
 
   def count(*n)
-    SQL.count(*n)
+    Rebel::SQL.count(*n)
   end
 
   def join(table, on: nil)
-    SQL.join(table, on: on)
+    Rebel::SQL.join(table, on: on)
   end
 
   def outer_join(table, on: nil)
-    SQL.outer_join(table, on: on)
+    Rebel::SQL.outer_join(table, on: on)
+  end
+end
+
+module Rebel
+  class Raw < String
+    def wants_parens!
+      @wants_parens = true
+      self
+    end
+
+    def wants_parens?
+      @wants_parens = false unless instance_variable_defined?(:@wants_parens)
+      @wants_parens
+    end
+
+    def parens
+      sql.raw("(#{self})")
+    end
+
+    def parens?
+      wants_parens? ? parens : self
     end
 
-  class Raw < String
     def as(n)
-      Raw.new(self + " AS #{SQL.name(n)}")
+      sql.raw(self + " AS #{sql.name(n)}")
     end
 
     def as?(n)
       n ? as(n) : self
     end
 
-    def on(clause)
-      Raw.new(self + " ON #{SQL.and_clause(clause)}")
+    def on(*clause)
+      sql.raw(self + " ON #{sql.and_clause(*clause)}")
     end
 
-    def on?(clause)
-      clause ? on(clause) : self
+    def on?(*clause)
+      clause.any? ? on(*clause) : self
+    end
+
+    def having(*clause)
+      sql.raw(self + " HAVING #{sql.and_clause(*clause)}")
+    end
+
+    def asc
+      sql.raw(self + " ASC")
+    end
+
+    def desc
+      sql.raw(self + " DESC")
+    end
+
+    def and(*clause)
+      sql.raw("#{self.parens?} AND #{sql.and_clause(*clause)}")
+    end
+    alias & and
+
+    def or(*clause)
+      sql.raw("#{self} OR #{sql.and_clause(*clause)}").wants_parens!
+    end
+    alias | or
+
+    def eq(n)
+      sql.raw("#{self} = #{sql.name_or_value(n)}")
+    end
+    alias == eq
+
+    def is(n)
+      sql.raw("#{self} IS #{sql.name_or_value(n)}")
+    end
+
+    def ne(n)
+      sql.raw("#{self} != #{sql.name_or_value(n)}")
+    end
+    alias != ne
+
+    def is_not(n)
+      sql.raw("#{self} IS NOT #{sql.name_or_value(n)}")
+    end
+
+    def lt(n)
+      sql.raw("#{self} < #{sql.name_or_value(n)}")
+    end
+    alias < lt
+
+    def gt(n)
+      sql.raw("#{self} > #{sql.name_or_value(n)}")
+    end
+    alias > gt
+
+    def le(n)
+      sql.raw("#{self} <= #{sql.name_or_value(n)}")
+    end
+    alias <= le
+
+    def ge(n)
+      sql.raw("#{self} >= #{sql.name_or_value(n)}")
+    end
+    alias >= ge
+
+    def in(*v)
+      sql.raw("#{self} IN (#{sql.values(*v)})")
+    end
+
+    def not_in(*v)
+      sql.raw("#{self} NOT IN (#{sql.values(*v)})")
+    end
+
+    def like(n)
+      sql.raw("#{self} LIKE #{sql.value(n)}")
+    end
+
+    def not_like(n)
+      sql.raw("#{self} NOT LIKE #{sql.value(n)}")
+    end
+
+    private
+
+    def sql
+      @sql ||= Rebel::SQLQ
     end
   end
 
-  class << self
+  module SQLB
     def raw(str)
-      Raw.new(str)
+      Raw.new(str).tap { |r| r.instance_variable_set(:@sql, self) }
     end
 
     def create_table(table_name, desc)
-      <<-SQL
-      CREATE TABLE #{SQL.name(table_name)} (
-        #{SQL.list(desc.map { |k, v| "#{SQL.name(k)} #{v}" })}
-      );
-      SQL
+      raw %[CREATE TABLE #{name(table_name)} (#{list(desc.map { |k, v| "#{name(k)} #{v}" })})]
     end
 
-    def select(*fields, from: nil, where: nil, inner: nil, left: nil, right: nil)
-      <<-SQL
-      SELECT #{names(*fields)} FROM #{name(from)}
-      #{SQL.inner?(inner)}
-      #{SQL.left?(left)}
-      #{SQL.right?(right)}
-      #{SQL.where?(where)};
-      SQL
+    def drop_table(table_name)
+      raw "DROP TABLE #{name(table_name)}"
+    end
+
+    def select(*fields, distinct: nil, from: nil, where: nil, inner: nil, left: nil, right: nil, group: nil, order: nil, limit: nil, offset: nil)
+      raw [
+        "SELECT #{distinct ? "DISTINCT #{names(*distinct)}" : names(*fields)}",
+        from?(from),
+        inner?(inner),
+        left?(left),
+        right?(right),
+        where?(where),
+        group?(group),
+        order?(order),
+        limit?(limit, offset),
+      ].compact.join(' ')
     end
 
     def insert_into(table_name, *rows)
-      <<-SQL
-      INSERT INTO #{SQL.name(table_name)} (#{SQL.names(*rows.first.keys)})
-      VALUES #{SQL.list(rows.map { |r| "(#{SQL.values(*r.values)})" })};
-      SQL
+      raw [
+        "INSERT INTO #{name(table_name)} (#{names(*rows.first.keys)})",
+        "VALUES #{list(rows.map { |r| "(#{values(*r.values)})" })}",
+      ].join(' ')
     end
 
     def update(table_name, set: nil, where: nil, inner: nil, left: nil, right: nil)
-      fail ArgumentError if set.nil?
+      raise ArgumentError if set.nil?
 
-      <<-SQL
-      UPDATE #{SQL.name(table_name)}
-      SET #{SQL.assign_clause(set)}
-      #{SQL.inner?(inner)}
-      #{SQL.left?(left)}
-      #{SQL.right?(right)}
-      #{SQL.where?(where)};
-      SQL
+      raw [
+        "UPDATE #{name(table_name)}",
+        "SET #{assign_clause(set)}",
+        inner?(inner),
+        left?(left),
+        right?(right),
+        where?(where),
+      ].compact.join(' ')
     end
 
     def delete_from(table_name, where: nil, inner: nil, left: nil, right: nil)
-      <<-SQL
-      DELETE FROM #{SQL.name(table_name)}
-      #{SQL.inner?(inner)}
-      #{SQL.left?(left)}
-      #{SQL.right?(right)}
-      #{SQL.where?(where)};
-      SQL
+      raw [
+        "DELETE FROM #{name(table_name)}",
+        inner?(inner),
+        left?(left),
+        right?(right),
+        where?(where),
+      ].join(' ')
     end
 
     def truncate(table_name)
-      <<-SQL
-      TRUNCATE #{SQL.name(table_name)};
-      SQL
+      raw "TRUNCATE #{name(table_name)}"
     end
 
     ## Functions
 
+    def function(name, *args)
+      raw("#{name}(#{names_or_values(*args)})")
+    end
+    alias fn function
+
+    def by(*n)
+      raw("BY #{names(*n)}")
+    end
+
     def count(*n)
       raw("COUNT(#{names(*n)})")
     end
@@ -137,13 +261,26 @@ module Rebel::SQL
       raw("OUTER JOIN #{name(table)}").on?(on)
     end
 
+    def inner_join(table, on: nil)
+      raw(inner? join(table, on: on))
+    end
+
+    def left_outer_join(table, on: nil)
+      raw(left? outer_join(table, on: on))
+    end
+
+    def right_outer_join(table, on: nil)
+      raw(right? outer_join(table, on: on))
+    end
+
     ## Support
 
-    def name(name)
+    def name(name = nil)
+      super() if name.nil? # workaround for pry and introspection
       return name if name.is_a?(Raw)
-      return raw('*') if name == '*'
+      return raw('*') if name == :*
 
-      name.to_s.split('.').map { |e| "\"#{e}\"" }.join('.')
+      raw(name.to_s.split('.').map { |e| "#{@identifier_quote}#{e}#{@identifier_quote}" }.join('.'))
     end
 
     def names(*names)
@@ -154,13 +291,22 @@ module Rebel::SQL
       items.join(', ')
     end
 
+    def escape_str(str)
+      str.dup.tap do |s|
+        s.gsub!('\\') { @escaped_string_backslash } if @escaped_string_backslash
+        s.gsub!(@string_quote) { @escaped_string_quote }
+      end
+    end
+
     def value(v)
       case v
       when Raw then v
-      when String then raw "'#{v.tr("'", "''")}'"
-      when Fixnum then raw v.to_s
+      when String then raw "#{@string_quote}#{escape_str(v)}#{@string_quote}"
+      when Integer then raw v.to_s
+      when TrueClass, FalseClass then raw(v ? @true_literal : @false_literal)
+      when Date, Time, DateTime then value(v.iso8601)
       when nil then raw 'NULL'
-      else fail NotImplementedError, v.inspect
+      else raise NotImplementedError, "#{v.class}: #{v.inspect}"
       end
     end
 
@@ -172,6 +318,10 @@ module Rebel::SQL
       item.is_a?(Symbol) ? name(item) : value(item)
     end
 
+    def names_or_values(*items)
+      list(items.map { |v| name_or_value(v) })
+    end
+
     def equal(l, r)
       "#{name_or_value(l)} = #{name_or_value(r)}"
     end
@@ -180,22 +330,35 @@ module Rebel::SQL
       list(clause.map { |k, v| equal(k, v) })
     end
 
-    def and_clause(clause)
-      return clause if clause.is_a?(Raw) || clause.is_a?(String)
+    def clause_term(left, right)
+      case right
+      when Array
+        name(left).in(*right)
+      when nil
+        name(left).is(name_or_value(right))
+      else
+        name(left).eq(name_or_value(right))
+      end
+    end
 
+    def and_clause(*clause)
       clause.map do |e|
         case e
-        when Array then "#{name(e[0])} = #{name_or_value(e[1])}"
-        when Raw, String then e
-        else fail NotImplementedError, e.class
+        when Hash then and_clause(*e.to_a)
+        when Array then clause_term(e[0], e[1])
+        when Raw then e.parens?
+        when String then e
+        else raise NotImplementedError, e.class
         end
       end.join(' AND ')
     end
 
-    def where?(clause)
-      return "WHERE #{clause}" if clause.is_a?(Raw) || clause.is_a?(String)
+    def from?(from)
+      from ? "FROM #{name(from)}" : nil
+    end
 
-      (clause && clause.any?) ? "WHERE #{SQL.and_clause(clause)}" : nil
+    def where?(*clause)
+      clause.any? ? "WHERE #{and_clause(*clause)}" : nil
     end
 
     def inner?(join)
@@ -209,5 +372,48 @@ module Rebel::SQL
     def right?(join)
       join ? "RIGHT #{join}" : nil
     end
+
+    def group?(group)
+      group ? "GROUP #{name(group)}" : nil
+    end
+
+    def order?(order)
+      order ? "ORDER #{name(order)}" : nil
+    end
+
+    def limit?(limit, offset)
+      limit ? "LIMIT #{value(limit)}" << (offset ? " OFFSET #{offset}" : "") : nil
+    end
   end
 end
+
+module Rebel
+  def self.SQL(options = {}, &block)
+    sql = const_defined?(:SQL) && options.empty? ? SQL : Module.new do
+      @identifier_quote = options[:identifier_quote] || '"'
+      @string_quote = options[:string_quote] || "'"
+      @escaped_string_quote = options[:escaped_string_quote] || "''"
+      @escaped_string_backslash = options[:escaped_string_backslash]
+      @true_literal = options[:true_literal] || 'TRUE'
+      @false_literal = options[:false_literal] || 'FALSE'
+
+      extend Rebel::SQLB
+      include Rebel::SQLQ
+
+      def self.name(name = nil)
+        return "Rebel::SQL" if name.nil?
+        super
+      end
+
+      def self.inspect
+        "#<Rebel::SQL(#{instance_variables.map { |k| "#{k.to_s.sub(/^@/, '')}: #{instance_variable_get(k).inspect}" }.join(', ')})>"
+      end
+    end
+
+    return sql.instance_eval(&block) unless block.nil?
+
+    sql
+  end
+
+  SQL = SQL()
+end

rebel.gemspec

@@ -1,11 +1,11 @@
 Gem::Specification.new do |s|
   s.name        = 'rebel'
-  s.version     = '0.1.0'
+  s.version     = '0.7.2'
   s.licenses    = ['MIT']
   s.summary     = 'Fight against the Object tyranny'
-  s.description = 'Write SQL queries in Ruby, or is it the other way around?'
+  s.description = 'SQL-flavoured Ruby, or is it the other way around?'
   s.authors     = ['Loic Nageleisen']
   s.email       = 'loic.nageleisen@gmail.com'
   s.files       = Dir['lib/**/*.rb']
-  s.homepage    = 'https://github.com/lloeki/rebel.git'
+  s.homepage    = 'https://gitlab.com/lloeki/rebel.git'
 end

test/helper.rb

@@ -0,0 +1,8 @@
+require 'pry'
+require 'sqlite3'
+
+def memdb
+  SQLite3::Database.new(':memory:').tap do |db|
+    db.class.instance_eval { alias_method :exec, :execute }
+  end
+end

test/test_exec.rb

@@ -0,0 +1,49 @@
+require 'minitest/autorun'
+require 'helper'
+require 'rebel'
+
+class TestExec < Minitest::Test
+  include Rebel::SQL
+
+  def setup
+    @conn = memdb
+  end
+
+  def test_create_table
+    assert_raises(SQLite3::SQLException) { conn.execute('SELECT * FROM foo') }
+    create_table :foo, id: 'INT', col: 'VARCHAR(255)'
+    assert_equal(conn.execute('SELECT * FROM foo'), [])
+  end
+
+  def test_drop_table
+    create_table :foo, id: 'INT', col: 'VARCHAR(255)'
+    assert_equal(conn.execute('SELECT * FROM foo'), [])
+    drop_table :foo
+    assert_raises(SQLite3::SQLException) { conn.execute('SELECT * FROM foo') }
+  end
+
+  def test_insert_into
+    create_table :foo, id: 'INT', col: 'VARCHAR(255)'
+    insert_into :foo, id: 1, col: 'whatevs'
+    assert_equal(conn.execute('SELECT * FROM foo'), [[1, 'whatevs']])
+  end
+
+  def test_insert_into_with_many_values
+    create_table :foo, id: 'INT', col: 'VARCHAR(255)'
+    insert_into :foo,
+                { id: 1, col: 'more' },
+                { id: 2, col: 'rows' },
+                { id: 3, col: 'for the win' }
+    assert_equal(conn.execute('SELECT * FROM foo'), [
+      [1, 'more'],
+      [2, 'rows'],
+      [3, 'for the win'],
+    ])
+  end
+
+  def test_select
+    create_table :foo, id: 'INT', col: 'VARCHAR(255)'
+    insert_into :foo, id: 1, col: 'whatevs'
+    assert_equal(select(:*, from: :foo), [[1, 'whatevs']])
+  end
+end

test/test_raw.rb

@@ -0,0 +1,246 @@
+require 'minitest/autorun'
+require 'helper'
+require 'rebel'
+
+class TestRaw < Minitest::Test
+  def assert_sql(expected, &actual)
+    assert_equal(expected.to_s, Rebel::SQL(&actual).to_s)
+  end
+
+  def assert_mysql(expected, &actual)
+    assert_equal(expected.to_s, Rebel::SQL(identifier_quote: '`', escaped_string_quote: "\\'", escaped_string_backslash: '\\', &actual).to_s)
+  end
+
+  def assert_sqlite(expected, &actual)
+    assert_equal(expected.to_s, Rebel::SQL(true_literal: '1', false_literal: '0', &actual).to_s)
+  end
+
+  def assert_postgresql(expected, &actual)
+    assert_equal(expected.to_s, Rebel::SQL(&actual).to_s)
+  end
+
+  def test_and
+    assert_sql('"foo" = 1 AND "bar" = 2') { name(:foo).eq(1).and(name(:bar).eq(2)) }
+    assert_sql('"foo" = 1 AND "bar" = 2') { name(:foo).eq(1) & name(:bar).eq(2) }
+    assert_sql('"foo" = 1 AND "bar" = 2') { (name(:foo) == 1) & (name(:bar) == 2) }
+  end
+
+  def test_or
+    assert_sql('"foo" = 1 OR "bar" = 2') { name(:foo).eq(1).or(name(:bar).eq(2)) }
+    assert_sql('"foo" = 1 OR "bar" = 2') { name(:foo).eq(1) | name(:bar).eq(2) }
+    assert_sql('"foo" = 1 OR "bar" = 2') { (name(:foo) == 1) | (name(:bar) == 2) }
+  end
+
+  def test_and_or
+    assert_sql('"foo" = 0 AND ("foo" = 1 OR "bar" = 2)') { name(:foo).eq(0).and(name(:foo).eq(1).or(name(:bar).eq(2))) }
+    assert_sql('"foo" = 0 AND ("foo" = 1 OR "bar" = 2)') { name(:foo).eq(0) & (name(:foo).eq(1) | name(:bar).eq(2)) }
+  end
+
+  def test_or_and_or
+    assert_sql('("foo" = 1 OR "bar" = 2) AND ("foo" = 3 OR "bar" = 4)') { name(:foo).eq(1).or(name(:bar).eq(2)).and(name(:foo).eq(3).or(name(:bar).eq(4))) }
+    assert_sql('("foo" = 1 OR "bar" = 2) AND ("foo" = 3 OR "bar" = 4)') { (name(:foo).eq(1) | name(:bar).eq(2)) & (name(:foo).eq(3) | name(:bar).eq(4)) }
+  end
+
+  def test_and_or_and
+    assert_sql('"foo" = 1 AND "bar" = 2 OR "foo" = 3 AND "bar" = 4') { name(:foo).eq(1).and(name(:bar).eq(2)).or(name(:foo).eq(3).and(name(:bar).eq(4))) }
+    assert_sql('"foo" = 1 AND "bar" = 2 OR "foo" = 3 AND "bar" = 4') { name(:foo).eq(1) & name(:bar).eq(2) | name(:foo).eq(3) & name(:bar).eq(4) }
+  end
+
+  def test_is
+    assert_sql('"foo" IS NULL') { name(:foo).is(nil) }
+    assert_sql('"foo" IS 42') { name(:foo).is(42) }
+    assert_sql('"foo" IS "bar"') { name(:foo).is(name(:bar)) }
+  end
+
+  def test_is_not
+    assert_sql('"foo" IS NOT NULL') { name(:foo).is_not(nil) }
+    assert_sql('"foo" IS NOT 42') { name(:foo).is_not(42) }
+    assert_sql('"foo" IS NOT "bar"') { name(:foo).is_not(name(:bar)) }
+  end
+
+  def test_eq
+    assert_sql('"foo" = NULL') { name(:foo).eq(nil) }
+    assert_sql('"foo" = NULL') { name(:foo) == nil }
+    assert_sql('"foo" = "bar"') { name(:foo).eq(name(:bar)) }
+    assert_sql('"foo" = "bar"') { name(:foo) == name(:bar) }
+  end
+
+  def test_ne
+    assert_sql('"foo" != "bar"') { name(:foo).ne(name(:bar)) }
+    assert_sql('"foo" != "bar"') { name(:foo) != name(:bar) }
+    assert_sql('"foo" != NULL') { name(:foo).ne(nil) }
+    assert_sql('"foo" != NULL') { name(:foo) != nil }
+  end
+
+  def test_lt
+    assert_sql('"foo" < "bar"') { name(:foo).lt(name(:bar)) }
+    assert_sql('"foo" < "bar"') { name(:foo) <  name(:bar) }
+  end
+
+  def test_gt
+    assert_sql('"foo" > "bar"') { name(:foo).gt(name(:bar)) }
+    assert_sql('"foo" > "bar"') { name(:foo) >  name(:bar) }
+  end
+
+  def test_le
+    assert_sql('"foo" <= "bar"') { name(:foo).le(name(:bar)) }
+    assert_sql('"foo" <= "bar"') { name(:foo) <= name(:bar) }
+  end
+
+  def test_ge
+    assert_sql('"foo" >= "bar"') { name(:foo).ge(name(:bar)) }
+    assert_sql('"foo" >= "bar"') { name(:foo) >= name(:bar) }
+  end
+
+  def test_in
+    assert_sql('"foo" IN (1, 2, 3)') { name(:foo).in(1, 2, 3) }
+  end
+
+  def test_not_in
+    assert_sql('"foo" NOT IN (1, 2, 3)') { name(:foo).not_in(1, 2, 3) }
+  end
+
+  def test_like
+    assert_sql(%("foo" LIKE '%bar%')) { name(:foo).like('%bar%') }
+  end
+
+  def test_not_like
+    assert_sql(%("foo" NOT LIKE '%bar%')) { name(:foo).not_like('%bar%') }
+  end
+
+  def test_where
+    assert_sql('WHERE "foo" = 1 AND "bar" = 2 AND "baz" = 3') { where?(foo: 1, bar: 2, baz: 3) }
+    assert_sql('WHERE ("foo" = 1 OR "bar" = 2) AND "baz" = 3') { where?(name(:foo).eq(1).or(name(:bar).eq(2)), name(:baz).eq(3)) }
+    assert_sql('WHERE ("foo" = 1 OR "bar" = 2)') { where?(name(:foo).eq(1).or(name(:bar).eq(2))) }
+    assert_sql('WHERE "foo" IS NULL') { where?(foo: nil) }
+    assert_sql('WHERE "foo" IN (1, 2, 3)') { where?(foo: [1, 2, 3]) }
+  end
+
+  def test_join
+    assert_sql('JOIN "foo"') { join(:foo) }
+  end
+
+  def test_function
+    assert_sql('COALESCE("foo", 0)') { function('COALESCE', :foo, 0) }
+  end
+
+  def test_where_function
+    assert_sql('WHERE COALESCE("foo", 0) = 42') { where?(function('COALESCE', :foo, 0).eq 42) }
+  end
+
+  def test_name
+    assert_sql('"foo"') { name(:foo) }
+    assert_mysql('`foo`') { name(:foo) }
+    assert_postgresql('"foo"') { name(:foo) }
+    assert_sqlite('"foo"') { name(:foo) }
+  end
+
+  def test_string
+    assert_sql("'FOO'") { value('FOO') }
+    assert_mysql("'FOO'") { value('FOO') }
+    assert_postgresql("'FOO'") { value('FOO') }
+    assert_sqlite("'FOO'") { value('FOO') }
+  end
+
+  def test_escaped_string
+    assert_sql        (%q('FOO''BAR'))   { value(%q(FOO'BAR))  }
+    assert_postgresql (%q('FOO''BAR'))   { value(%q(FOO'BAR))  }
+    assert_sqlite     (%q('FOO''BAR'))   { value(%q(FOO'BAR))  }
+    assert_mysql      (%q('FOO\'BAR'))   { value(%q(FOO'BAR))  }
+
+    assert_sql        (%q('FOO"BAR'))    { value(%q(FOO"BAR))  }
+    assert_postgresql (%q('FOO"BAR'))    { value(%q(FOO"BAR))  }
+    assert_sqlite     (%q('FOO"BAR'))    { value(%q(FOO"BAR))  }
+    assert_mysql      (%q('FOO"BAR'))    { value(%q(FOO"BAR))  }
+
+    assert_sql        (%q('FOO\BAR'))    { value(%q(FOO\BAR))  }
+    assert_postgresql (%q('FOO\BAR'))    { value(%q(FOO\BAR))  }
+    assert_sqlite     (%q('FOO\BAR'))    { value(%q(FOO\BAR))  }
+    assert_mysql      (%q('FOO\\BAR'))   { value(%q(FOO\BAR))  }
+
+    assert_sql        (%q('FOO\\''BAR')) { value(%q(FOO\'BAR)) }
+    assert_postgresql (%q('FOO\\''BAR')) { value(%q(FOO\'BAR)) }
+    assert_sqlite     (%q('FOO\\''BAR')) { value(%q(FOO\'BAR)) }
+    assert_mysql      (%q('FOO\\\'BAR')) { value(%q(FOO\'BAR)) }
+  end
+
+  def test_boolean_literal
+    assert_sql('TRUE') { value(true) }
+    assert_mysql('TRUE') { value(true) }
+    assert_postgresql('TRUE') { value(true) }
+    assert_sqlite('1') { value(true) }
+
+    assert_sql('FALSE') { value(false) }
+    assert_mysql('FALSE') { value(false) }
+    assert_postgresql('FALSE') { value(false) }
+    assert_sqlite('0') { value(false) }
+  end
+
+  def test_value
+    assert_sql("'FOO'") { value(raw("'FOO'")) }
+    assert_sql("'FOO'") { value('FOO') }
+    assert_sql('1') { value(1) }
+    assert_sql('TRUE') { value(true) }
+    assert_sql('FALSE') { value(false) }
+    assert_sql("'2016-12-31'") { value(Date.new(2016, 12, 31)) }
+    assert_sql("'2016-12-31T23:59:59Z'") { value(Time.utc(2016, 12, 31, 23, 59, 59)) }
+    assert_sql("'2016-12-31T23:59:59+00:00'") { value(DateTime.new(2016, 12, 31, 23, 59, 59)) }
+    assert_sql('NULL') { value(nil) }
+  end
+
+  def test_select
+    assert_sql('SELECT * FROM "foo"') { select(raw('*'), from: name(:foo)) }
+  end
+
+  def test_select_without_from
+    assert_sql('SELECT 1') { select(raw('1')).strip }
+  end
+
+  def test_select_distinct
+    assert_sql('SELECT DISTINCT "bar" FROM "foo"') { select(distinct: :bar, from: :foo) }
+  end
+
+  def test_select_distinct_multiple
+    assert_sql('SELECT DISTINCT "bar", "baz" FROM "foo"') { select(distinct: [:bar, :baz], from: :foo) }
+  end
+
+  def test_select_group_by
+    assert_sql('SELECT "bar" FROM "foo" GROUP BY "baz"') { select(:bar, from: :foo, group: by(:baz)) }
+  end
+
+  def test_select_group_by_having
+    assert_sql('SELECT "bar" FROM "foo" GROUP BY "baz" HAVING COUNT("qux") > 5') { select(:bar, from: :foo, group: by(:baz).having(count(:qux).gt(5))) }
+  end
+
+  def test_select_order_by
+    assert_sql('SELECT "bar" FROM "foo" ORDER BY "baz"') { select(:bar, from: :foo, order: by(:baz)) }
+  end
+
+  def test_select_order_by_asc
+    assert_sql('SELECT "bar" FROM "foo" ORDER BY "baz" ASC') { select(:bar, from: :foo, order: by(:baz).asc) }
+  end
+
+  def test_select_order_by_desc
+    assert_sql('SELECT "bar" FROM "foo" ORDER BY "baz" DESC') { select(:bar, from: :foo, order: by(:baz).desc) }
+  end
+
+  def test_select_multiple_order_by
+    assert_sql('SELECT "bar" FROM "foo" ORDER BY "baz", "qux"') { select(:bar, from: :foo, order: by(:baz, :qux)) }
+  end
+
+  def test_select_multiple_order_by_opposing
+    assert_sql('SELECT "bar" FROM "foo" ORDER BY "baz" ASC, "qux" DESC') { select(:bar, from: :foo, order: by(name(:baz).asc, name(:qux).desc)) }
+  end
+
+  def test_select_limit
+    assert_sql('SELECT "bar" FROM "foo" LIMIT 10') { select(:bar, from: :foo, limit: 10) }
+  end
+
+  def test_select_offset
+    assert_sql('SELECT "bar" FROM "foo" LIMIT 10 OFFSET 20') { select(:bar, from: :foo, limit: 10, offset: 20) }
+  end
+
+  def test_nested_select
+    assert_sql('SELECT * FROM "foo" WHERE "bar" IN (SELECT "bar" FROM "foo")') { select(raw('*'), from: name(:foo), where: name(:bar).in(select(name(:bar), from: name(:foo)))) }
+  end
+end