- See also
- - https://sicstus.sics.se/sicstus/docs/4.6.0/html/sicstus.html/lib_002dterms.html
- To be done
- - This library is incomplete.
As of SICStus 4.6.0, the following predicates are missing:
- term_hash/3
- depth_bound/2
- length_bound/2
- size_bound/2
- term_depth/2
- term_variables_set(@Term, -Variables) is det
- Same as term_variables_bag/2, but Variables is an ordered set.
- subsumeschk(+Generic, @Specific) is semidet
- SICStus 4 name of subsumes_chk/2.
- deprecated
- - Replace by subsumes_term/2.
- term_order(@X, @Y, -R) is det
- Same as compare/3, except for the order of arguments.
- deprecated
- - Use the standard compare/3 instead.
Re-exported predicates
The following predicates are exported from this file while their implementation is defined in imported modules or non-module files loaded by this module.
- foldsubterms(:Goal3, +Term1, +State0, -State) is semidet
- foldsubterms(:Goal4, +Term1, ?Term2, +State0, -State) is semidet
- 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.
- 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.
- free_of_var(+Sub, +Term)
- Succeeds of Sub is not equal (==) to any subterm of Term
- 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.
- term_variables_bag(+Term, -Variables) is det
- Variables is a list of variables that appear in Term. The
variables are ordered according to depth-first left-right walking
of the term. Variables contains no duplicates. This is the same
as SWI-Prolog's term_variables/2.
- same_functor(?Term1, ?Term2) is semidet
- same_functor(?Term1, ?Term2, -Arity) is semidet
- same_functor(?Term1, ?Term2, ?Name, ?Arity) is semidet
- 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
- sub_term(-Sub, +Term)
- Generates (on backtracking) all subterms of Term.
- mapsubterms(:Goal, +Term1, -Term2) is det
- mapsubterms_var(:Goal, +Term1, -Term2) is det
- 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
- 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.
- free_of_term(+Sub, +Term)
- Succeeds of Sub does not unify to any subterm of Term
- subsumes_chk(@Generic, @Specific)
- True if Generic can be made equivalent to Specific without
changing Specific.
- deprecated
- - Replace by subsumes_term/2.
- same_functor(?Term1, ?Term2) is semidet
- same_functor(?Term1, ?Term2, -Arity) is semidet
- same_functor(?Term1, ?Term2, ?Name, ?Arity) is semidet
- 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
- mapsubterms(:Goal, +Term1, -Term2) is det
- mapsubterms_var(:Goal, +Term1, -Term2) is det
- 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
- 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.
- same_functor(?Term1, ?Term2) is semidet
- same_functor(?Term1, ?Term2, -Arity) is semidet
- same_functor(?Term1, ?Term2, ?Name, ?Arity) is semidet
- 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
- term_subsumer(+Special1, +Special2, -General) is det
- 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
- occurrences_of_var(+SubTerm, +Term, ?Count)
- Count the number of SubTerms in Term
- contains_var(+Sub, +Term) is det
- Succeeds if Sub is contained in Term (==, deterministically)
- term_size(@Term, -Size) is det
- 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.
- foldsubterms(:Goal3, +Term1, +State0, -State) is semidet
- foldsubterms(:Goal4, +Term1, ?Term2, +State0, -State) is semidet
- 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.
- occurrences_of_term(+SubTerm, +Term, ?Count)
- Count the number of SubTerms in Term
- 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)].
- contains_term(+Sub, +Term) is semidet
- Succeeds if Sub is contained in Term (=, deterministically)
- variant(@Term1, @Term2) is semidet
- Same as SWI-Prolog
Term1 =@= Term2
.
Undocumented predicates
The following predicates are exported, but not or incorrectly documented.
- cyclic_term(Arg1)
- term_hash(Arg1, Arg2, Arg3, Arg4)
- term_variables(Arg1, Arg2, Arg3)
- term_hash(Arg1, Arg2)