A typical application may define a small pool of threads with large stacks for computation intensive tasks, and a large pool of threads with small stacks to serve media. The declaration could be the one below, allowing for max 3 concurrent solvers and a maximum backlog of 5 and 30 tasks creating image thumbnails. Xpce is used at swi for the development of knowledgeintensive graphical applications. The main design objectives of the foreign language interface are flexibility and performance. Swi prolog 53 reference manual initialising and managing a. Library predicates differ from builtin predicates in the following ways. Swi prolog syntax is close to iso prolog standard syntax, which is closely compatible with edinburgh prolog syntax. Plain prolog can thus be regarded as a special case of clp. Keeping operators in modules and using controlled importexport of operators as described with the module 2 directive keep the issues manageable.
The swiprolog implementation is cyclesafe and can deal with variables that are shared between the left and right argument. Vu university amsterdam university of amsterdam swiprolog. A foreign predicate is a c function that has the same number of arguments as the predicate represented. Part of the library is therefore documented in the rest of the manual. Swi prolog aims to be a robust and scalable implementation supporting a. Aim of this lecture 2 2 introduce other concepts, such as the role of logic unification with the help of variables begin the systematic study of prolog by defining terms atoms, and variables. The optional unify port allows the user to inspect the result after unification of the head. Tag confusing pages with docneedshelp tags are associated to your profile if you are logged in. Unlike edinburgh prolog systems, telling1 and seeing1 do not return the filename of the current inputoutput but rather the stream identifier, to ensure the design pattern below works under all circumstances. The primary database is defined by the predicate predicate 5 we will make hyperlinks for the predicates pointing to their documentation. In section 2 we describe the development of swiprolog, with a particular. The module system provides the operators from table 5 and these operators cannot be modified. Swi prolog started back in 1986 with the requirement for a prolog that could handle recursive inter action with the clanguage.
To reach at a compiled cprogram with swiprolog as an embedded application is very similar to creating a statically linked swiprolog executable as described in section 5. Swi kruislaan 419, 1098 va amsterdam the netherlands tel. Prolog realizes highorder programming with metacalling. Swi prolog is a comprehensive and portable implementation of the prolog programming language. Introduction to prolog programming homepages of uvafnwi staff. Plain prolog can be regarded as clph, where h stands for herbrand terms. In swiprolog, operators are local to a module see also section 6. As swi prolog provides autoloading, there is little difference between library predicates and builtin predicates. The application range includes prolog course material, metainterpreters, simulation of parallel prolog,learningsystems,naturallanguageprocessing,complexinteractivesystems,webserverandwebserver components. These notes have originally been developed for a course i taught at kings college london in 1999 and 2000.
This predicate is known by the name variant 2 in some. It is widely used in research and education as well as for commercial applications. This is the official reference manual for the latest version of swi prolog. Swiprolog has been designed and implemented such that it. Product information, documentation and additional resources specific to. The application range includes prolog course material, metainterpreters, simulation of parallel prolog, learning systems, natural language processing and two large workbenches for knowledge engineering. They have been introduced to make translation of old code easier, but also because they provide for a faster mechanism for returning data to prolog. Resources however can be represented in two different formats. Its performance is comparable to 2, both on success and early failure. It provides access to whether optional features are available on this version, operating system, foreigncode environment, commandline arguments, version, as well as runtime flags to control the runtime behaviour of certain. That means that it documents the system, but it does not explain the basics of the prolog language and it leaves many details of the syntax, semantics and builtin primitives undefined where swi prolog follows the standards. The intention was to build a prolog environment which offers enough power and.
Swi prolog extends the minimal set of instructions described in bowen et al. A description of this syntax can be found in the prolog. Commercial users may consider contacting the developers 6 mailto. As soon as you start up swi prolog, you will see the message. There are dedicated constraint solvers for several important domains. The functions of this sections unify terms with other terms or translated cdata structures. Swi prolog 53 reference manual initialising and managing a prolog project 3 from cs 91. Over this domain, 2 and dif 2 are the most important constraints that express, respectively, equality and disequality of terms. Swi prolog offers a comprehensive and portable freesoftware prolog programming environment for more than 25 years now. As swi prolog became more popular, a large usercommunity provided requirements. This can be used to define higherorder predicates such as ignore1 or forall 2. This manual is intended for people that are familiar with prolog. The core predicate of this is call1, which simply calls its argument. In the following example we will generate a table of prolog predicates we find from the swiprolog help system based on a keyword.