[triqs/clef] Clef: Compile-time lazy expressions and functions

Warning

This library is still a prototype. Its basic features are used in our codes, but there are probably still some dark corners …

Documentation in progress.

The CLEF library (Compile time Lazy Expressions and Functions) is a little library to manipulate simple expressions at compile-time and use them e.g. to automatically fill containers.

• Motivation: a little tour of CLEF
• Forming CLEF expressions
  • Placeholders
  • Forming an expression
  • Storage of expressions [advanced]
• Evaluating CLEF expressions
  • Complete evaluation
  • Partial evaluation
• Automatic assignment of containers
• Overloading functions and methods for CLEF arguments
  • Overloading functions
  • Overloading operator() and other methods
• Transform CLEF expressions into functions
  • make_function
  • clef::function
  • Examples
• More complex examples
  • A lazy sum