The list below summarises the classes defined in the C++ interface.
- PlTerm
- Generic Prolog term that wraps
term_t (for more details on
term_t, see
Interface
Data Types). This is a "base class" whose constructor is protected;
subclasses specify the actual contents. Additional methods allow
checking the Prolog type, unification, comparison, conversion to native
C++-data types, etc. See section 2.9.3.
The subclass constructors are as follows. If a constructor fails
(e.g., out of memory), a PlException is thrown.
- PlTerm_atom
- Subclass of
PlTerm with constructors for building a term
that contains an atom.
- PlTerm_var
- Subclass of
PlTerm with constructors for building a term
that contains an uninstantiated variable. Typically this term is then
unified with another object.
- PlTerm_term_t
- Subclass of
PlTerm with constructors for building a term
from a C term_t.
- PlTerm_integer
- Subclass of
PlTerm with constructors for building a term
that contains a Prolog integer from a
long.9PL_put_integer()
takes a long argument.
- PlTerm_int64
- Subclass of
PlTerm with constructors for building a term
that contains a Prolog integer from a int64_t.
- PlTerm_uint64
- Subclass of
PlTerm with constructors for building a term
that contains a Prolog integer from a uint64_t.
- PlTerm_size_t
- Subclass of
PlTerm with constructors for building a term
that contains a Prolog integer from a size_t.
- PlTerm_float
- Subclass of
PlTerm with constructors for building a term
that contains a Prolog float.
- PlTerm_pointer
- Subclass of
PlTerm with constructors for building a term
that contains a raw pointer. This is mainly for backwards compatibility;
new code should use blobs.
- PlTerm_string
- Subclass of
PlTerm with constructors for building a term
that contains a Prolog string object.
- PlTerm_list_codes
- Subclass of
PlTerm with constructors for building Prolog
lists of character integer values.
- PlTerm_chars
- Subclass of
PlTerm with constructors for building Prolog
lists of one-character atoms (as atom_chars/2).
- PlTerm_tail
- SubClass of
PlTerm for building and analysing Prolog lists.
Additional subclasses of PlTerm are:
- PlCompound
- Subclass of
PlTerm with constructors for building compound
terms. If there is a single string argument, then PL_chars_to_term()
or PL_wchars_to_term() is used to parse the string and create the
term. If the constructor has two arguments, the first is name of a
functor and the second is a PlTermv with the arguments.
- PlTermv
- Vector of Prolog terms. See PL_new_term_refs(). The
[]PlTermv
is used to build complex terms and provide argument-lists to Prolog
goals.
- PlException
- Subclass of
PlTerm representing a Prolog exception.
Provides methods for the Prolog communication and mapping to
human-readable text representation.
- PlTypeError
- Subclass of
PlException for representing a Prolog
type_error exception.
- PlDomainError
- Subclass of
PlException for representing a Prolog
domain_error exception.
- PlExistenceError
- Subclass of
PlException for representing a Prolog
existence_error exception.
- PlPermissionError
- Subclass of
PlException for representing a Prolog
permission_error exception.
- PlAtom
- Allow for manipulating atoms (
atom_t) in their internal
Prolog representation for fast comparison. (For more details on
atom_t, see
Interface
Data Types).
- PlFunctor
- A wrapper for
functor_t, which maps to the internal
representation of a name/arity pair.
- PlPredicate
- A wrapper for
predicate_t, which maps to the internal
representation of a Prolog predicate.
- PlModule
- A wrapper for
module_t, which maps to the internal
representation of a Prolog module.
- PlQuery
- Represents opening and enumerating the solutions to a Prolog query.
- PlFail
- Can be thrown to short-circuit processing and return failure to Prolog.
Performance-critical code should use
return false instead
if failure is expected.
- PlFrame
- This utility-class can be used to discard unused term-references as well
as to do‘data-backtracking’.
- PlEngine
- This class is used in embedded applications (applications where
the main control is held in C++). It provides creation and destruction
of the Prolog environment.
- PlRegister
- The encapsulation of PL_register_foreign() is defined to be able
to use C++ global constructors for registering foreign predicates.
The required C++ function header and registration of a predicate is
arranged through a macro called PREDICATE().
