Treffer: Lazy Versus Strict.

The article presents a comparative analysis of lazy and strict languages. Lazy or call-by-need languages schedule work dynamically by building closures and shunning side effect while strict or call-by-value languages avoid the overhead of closures and may exploit side effects. Each style has complementary advantages and complementary adherents. The gap between the lazy and strict camps has two dimensions, which we shall name style and models. Lazy evaluation is essential to manage interaction with the database, which returns potentially enormous data structures. Over 20 commercial applications have been developed in Natural Expert, including IVANHOE, which invoices services for every flight passing through Orly or Roissy airport in Paris. Erlang is a strict functional language used by Ericsson Inc. to program telecommunications switches. Erlang fuses ideas from functional and concurrent languages. On the functional side it provides ease of allocating, traversing, and de-allocating complex structures, on the concurrent side it provides processes, message passing, and distribution. Several hundreds of thousands of lines of Erlang code appear in Ericsson products, and it has been found to be superior to C + + on a number of projects.