Updated README

README.md

@@ -2,7 +2,7 @@
 
 Micrate is a database migration tool written in crystal.
 
-It is shamelessly inspired by [goose](https://bitbucket.org/liamstask/goose/). Much of the code was ported from there, so check it out.
+It is inspired by [goose](https://bitbucket.org/liamstask/goose/). Some code was ported from there too, so check it out.
 
 This is still a work in progress!
 
@@ -23,7 +23,7 @@ dependencies:
     github: juanedi/micrate
 ```
 
-If you need to use micrate's CLI without installing the tool (which could be convenient in a CI environment) you can create a simple script like the following:
+This allows you to programatically use micrate's features. You'll see the `Micrate` module has an equivalent for every CLI command. If you need to use micrate's CLI without installing the tool (which could be convenient in a CI environment) you can create a simple script like the following:
 
 ```crystal
 #! /usr/bin/env crystal
@@ -57,19 +57,16 @@ Comments that start with `+micrate` are interpreted by micrate when running your
 
 ```sql
 -- +micrate Up
--- SQL in section 'Up' is executed when this migration is applied
 CREATE TABLE users(id INT PRIMARY KEY, email VARCHAR NOT NULL);
 
 -- +micrate Down
--- SQL section 'Down' is executed when this migration is rolled back
 DROP TABLE users;
 ```
-
 Now run it using `micrate up`. This command will execute all pending migrations:
 
 ```
 $ micrate up
-micrate: migrating db, current version: 0, target: 20160524162947
+Migrating db, current version: 0, target: 20160524162947
 OK   20160524162446_add_users_table.sql
 
 $ micrate dbversion # at any time you can find out the current version of the database
@@ -80,11 +77,38 @@ If you ever need to roll back the last migration, you can do so by executing `mi
 
 ```
 $ micrate status
-micrate: status
-    Applied At                  Migration
-    =======================================
-    2016-05-24 16:31:07 UTC  -- 20160524162446_add_users_table.sql
-    Pending                  -- 20160524163425_add_address_to_users.sql
+Applied At                  Migration
+=======================================
+2016-05-24 16:31:07 UTC  -- 20160524162446_add_users_table.sql
+Pending                  -- 20160524163425_add_address_to_users.sql
+```
+
+If using complex statements that might contain semicolons, you must give micrate a hint on how to split the script into separate statements. You can do this with `StatementBegin` and `StatementEnd` directives: (thanks [goose](https://bitbucket.org/liamstask/goose/) for this!)
+
+```
+-- +micrate Up
+-- +micrate StatementBegin
+CREATE OR REPLACE FUNCTION histories_partition_creation( DATE, DATE )
+returns void AS $$
+DECLARE
+  create_query text;
+BEGIN
+  FOR create_query IN SELECT
+      'CREATE TABLE IF NOT EXISTS histories_'
+      || TO_CHAR( d, 'YYYY_MM' )
+      || ' ( CHECK( created_at >= timestamp '''
+      || TO_CHAR( d, 'YYYY-MM-DD 00:00:00' )
+      || ''' AND created_at < timestamp '''
+      || TO_CHAR( d + INTERVAL '1 month', 'YYYY-MM-DD 00:00:00' )
+      || ''' ) ) inherits ( histories );'
+    FROM generate_series( $1, $2, '1 month' ) AS d
+  LOOP
+    EXECUTE create_query;
+  END LOOP;  -- LOOP END
+END;         -- FUNCTION END
+$$
+language plpgsql;
+-- +micrate StatementEnd
 ```
 
 ## Contributing

src/micrate/migration.cr

@@ -9,6 +9,10 @@ module Micrate
     def initialize(@version : Int64, @name : String, @source : String)
     end
 
+    # Algorithm ported from Goose
+    #
+    # Complex statements cannot be resolved by just splitting the script by semicolons.
+    # In this cases we allow using StatementBegin and StatementEnd directives as hints.
     def statements(direction)
       statements = [] of String