Compatibility library for term manipulation predicates. Most predicates
in this library are provided as SWI-Prolog built-ins.
- Compatibility
- - YAP, SICStus, Quintus. Not all versions of this library define
exactly the same set of predicates, but defined predicates are
compatible.
- 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.
- variant(@Term1, @Term2) is semidet
- 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.
- 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
- 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)].
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)