- 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(fastrw): Fast reading and writing of terms
- library(gensym): Generate unique symbols
- library(heaps): heaps/priority queues
- library(increval): Incremental dynamic predicate modification
- 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(macros): Macro expansion
- library(main): Provide entry point for scripts
- library(nb_set): Non-backtrackable set
- library(www_browser): Open a URL in the users 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(portray_text): Portray text
- library(predicate_options): Declare option-processing of predicates
- library(prolog_coverage): Coverage analysis tool
- library(prolog_debug): User level debugging tools
- library(prolog_jiti): Just In Time Indexing (JITI) utilities
- library(prolog_trace): Print access to predicates
- library(prolog_versions): Demand specific (Prolog) versions
- library(prolog_xref): Prolog cross-referencer data collection
- library(quasi_quotations): Define Quasi Quotation syntax
- library(random): Random numbers
- library(rbtrees): Red black trees
- library(readutil): Read utilities
- library(record): Access named fields in a term
- library(registry): Manipulating the Windows registry
- library(rwlocks): Read/write locks
- library(settings): Setting management
- library(statistics): Get information about resource usage
- 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): Graph manipulation library
- library(url): Analysing and constructing URL
- library(varnumbers): Utilities for numbered terms
- library(yall): Lambda expressions

- The SWI-Prolog library
- Packages

- Reference manual

## A.57 library(terms): Term manipulation

- Compatibility
- YAP, SICStus, Quintus. Not all versions of this library define exactly the same set of predicates, but defined predicates are compatible.

Compatibility library for term manipulation predicates. Most predicates in this library are provided as SWI-Prolog built-ins.

- [det]
**term_size**(`@Term, -Size`) - True if
`Size`is the size in*cells*occupied by`Term`on the global (term) stack. A*cell*is 4 bytes on 32-bit machines and 8 bytes on 64-bit machines. The calculation does take*sharing*into account. For example:?- A = a(1,2,3), term_size(A,S). S = 4. ?- A = a(1,2,3), term_size(a(A,A),S). S = 7. ?- term_size(a(a(1,2,3), a(1,2,3)), S). S = 11.

Note that small objects such as atoms and small integers have a size 0. Space is allocated for floats, large integers, strings and compound terms.

- [semidet]
**variant**(`@Term1, @Term2`) - Same as SWI-Prolog
`Term1 =@= Term2`

. **subsumes_chk**(`@Generic, @Specific`)- True if
`Generic`can be made equivalent to`Specific`without changing`Specific`.- deprecated
- Replace by subsumes_term/2.

**subsumes**(`+Generic, @Specific`)- True if
`Generic`is unified to`Specific`without changing`Specific`.- deprecated
- It turns out that calls to this predicate almost always should have used subsumes_term/2. Also the name is misleading. In case this is really needed, one is adviced to follow subsumes_term/2 with an explicit unification.

- [det]
**term_subsumer**(`+Special1, +Special2, -General`) `General`is the most specific term that is a generalisation of`Special1`and`Special2`. The implementation can handle cyclic terms.- author
- Inspired by LOGIC.PRO by Stephen Muggleton
- Compatibility
- SICStus

**term_factorized**(`+Term, -Skeleton, -Substiution`)- Is true when
`Skeleton`is`Term`where all subterms that appear multiple times are replaced by a variable and Substitution is a list of Var=Value that provides the subterm at the location Var. I.e., After unifying all substitutions in Substiutions,`Term``==`

`Skeleton`.`Term`may be cyclic. For example:?- X = a(X), term_factorized(b(X,X), Y, S). Y = b(_G255, _G255), S = [_G255=a(_G255)].

**mapargs**(`:Goal, ?Term1, ?Term2`)`Term1`and`Term2`have the same functor (name/arity) and for each matching pair of arguments`call(Goal, A1, A2)`

is true.- [det]
**mapsubterms**(`:Goal, +Term1, -Term2`) - [det]
**mapsubterms_var**(`:Goal, +Term1, -Term2`) - Recursively map sub terms of
`Term1`into subterms of`Term2`for every pair for which`call(Goal, ST1, ST2)`

succeeds. Procedurably, the mapping for each (sub) term pair`T1/T2`

is defined as:- If
`T1`is a variable- mapsubterms/3
unifies
`T2`with`T1`. - mapsubterms_var/3 treats variables as other terms.

- mapsubterms/3
unifies
- If
`call(Goal, T1, T2)`

succeeds we are done. Note that the mapping does not continue in`T2`. If this is desired,`Goal`must call mapsubterms/3 explicitly as part of its conversion. - If
`T1`is a dict, map all values, i.e., the*tag*and*keys*are left untouched. - If
`T1`is a list, map all elements, i.e., the list structure is left untouched. - If
`T1`is a compound, use same_functor/3 to instantiate`T2`and recurse over the term arguments left to right. - Otherwise
`T2`is unified with`T1`.

Both predicates are implemented using foldsubterms/5.

- If
- [semidet]
**foldsubterms**(`:Goal3, +Term1, +State0, -State`) - [semidet]
**foldsubterms**(`:Goal4, +Term1, ?Term2, +State0, -State`) - The predicate foldsubterms/5
calls
`call(Goal4, SubTerm1, SubTerm2, StateIn, StateOut)`

for each subterm, including variables, in`Term1`. If this call fails,`StateIn`and`StateOut`are the same. This predicate may be used to map subterms in a term while collecting state about the mapped subterms. The foldsubterms/4 variant does not map the term. - [semidet]
**same_functor**(`?Term1, ?Term2`) - [semidet]
**same_functor**(`?Term1, ?Term2, -Arity`) - [semidet]
**same_functor**(`?Term1, ?Term2, ?Name, ?Arity`) - True when
`Term1`and`Term2`are terms that have the same functor (`Name`/`Arity`). The arguments must be sufficiently instantiated, which means either`Term1`or`Term2`must be bound or both`Name`and`Arity`must be bound.If

`Arity`is 0,`Term1`and`Term2`are unified with`Name`for compatibility.- Compatibility
- SICStus