- Documentation
- Reference manual
- The SWI-Prolog library
- library(aggregate): Aggregation operators on backtrackable predicates
- library(ansi_term): Print decorated text to ANSI consoles
- library(apply): Apply predicates on a list
- library(assoc): Association lists
- library(broadcast): Broadcast and receive event notifications
- library(charsio): I/O on Lists of Character Codes
- library(check): Consistency checking
- library(clpb): CLP(B): Constraint Logic Programming over Boolean Variables
- library(clpfd): CLP(FD): Constraint Logic Programming over Finite Domains
- library(clpqr): Constraint Logic Programming over Rationals and Reals
- library(csv): Process CSV (Comma-Separated Values) data
- library(dcg/basics): Various general DCG utilities
- library(dcg/high_order): High order grammar operations
- library(debug): Print debug messages and test assertions
- library(dicts): Dict utilities
- library(error): Error generating support
- library(gensym): Generate unique identifiers
- library(intercept): Intercept and signal interface
- library(iostream): Utilities to deal with streams
- library(listing): List programs and pretty print clauses
- library(lists): List Manipulation
- library(main): Provide entry point for scripts
- library(nb_set): Non-backtrackable set
- library(www_browser): Activating your Web-browser
- library(occurs): Finding and counting sub-terms
- library(option): Option list processing
- library(optparse): command line parsing
- library(ordsets): Ordered set manipulation
- library(pairs): Operations on key-value lists
- library(persistency): Provide persistent dynamic predicates
- library(pio): Pure I/O
- library(predicate_options): Declare option-processing of predicates
- library(prolog_jiti): Just In Time Indexing (JITI) utilities
- library(prolog_pack): A package manager for Prolog
- library(prolog_xref): Prolog cross-referencer data collection
- library(quasi_quotations): Define Quasi Quotation syntax
- library(random): Random numbers
- library(readutil): Read utilities
- library(record): Access named fields in a term
- library(registry): Manipulating the Windows registry
- library(settings): Setting management
- library(strings): String utilities
- library(simplex): Solve linear programming problems
- library(solution_sequences): Modify solution sequences
- library(tables): XSB interface to tables
- library(terms): Term manipulation
- library(thread): High level thread primitives
- library(thread_pool): Resource bounded thread management
- library(ugraphs): Unweighted Graphs
- library(url): Analysing and constructing URL
- library(varnumbers): Utilities for numbered terms
- library(yall): Lambda expressions
- The SWI-Prolog library
- Packages
- Reference manual
A.25 library(occurs): Finding and counting sub-terms
- See also
library(terms)provides similar predicates and is probably more wide-spread than this library.
This is a SWI-Prolog implementation of the corresponding Quintus library, based on the generalised arg/3 predicate of SWI-Prolog.
- [semidet]contains_term(+Sub, +Term)
- Succeeds if Sub is contained in Term (=, deterministically)
- [det]contains_var(+Sub, +Term)
- Succeeds if Sub is contained in Term (==, deterministically)
- free_of_term(+Sub, +Term)
- Succeeds of Sub does not unify to any subterm of Term
- free_of_var(+Sub, +Term)
- Succeeds of Sub is not equal (
==) to any subterm of Term - occurrences_of_term(+SubTerm, +Term, ?Count)
- Count the number of SubTerms in Term
- occurrences_of_var(+SubTerm, +Term, ?Count)
- Count the number of SubTerms in Term
- sub_term(-Sub, +Term)
- Generates (on backtracking) all subterms of Term.
- sub_var(-Sub, +Term)
- Generates (on backtracking) all subterms (
==) of Term. - [det]sub_term_shared_variables(+Sub, +Term, -Vars)
- If Sub is a sub term of Term, Vars is
bound to the list of variables in Sub that also appear
outside Sub in Term. Note that if Sub
appears twice in Term, its variables are all considered
shared.
An example use-case is refactoring a large clause body by introducing intermediate predicates. This predicate can be used to find the arguments that must be passed to the new predicate.