Method: SQLite3::Database#create_function

Defined in:
lib/sqlite3/database.rb

#create_function(name, arity, text_rep = Constants::TextRep::ANY, &block) ⇒ Object

Creates a new function for use in SQL statements. It will be added as name, with the given arity. (For variable arity functions, use -1 for the arity.)

The block should accept at least one parameter--the FunctionProxy instance that wraps this function invocation--and any other arguments it needs (up to its arity).

The block does not return a value directly. Instead, it will invoke the FunctionProxy#result= method on the func parameter and indicate the return value that way.

Example:

db.create_function( "maim", 1 ) do |func, value|
if value.nil?
  func.result = nil
else
  func.result = value.split(//).sort.join
end
end

puts db.get_first_value( "select maim(name) from table" )


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# File 'lib/sqlite3/database.rb', line 319

def create_function name, arity, text_rep=Constants::TextRep::ANY, &block
  define_function(name) do |*args|
    fp = FunctionProxy.new
    block.call(fp, *args)
    fp.result
  end
  self
end