Syntax of meta-type

StructureKind ::= mclause | mpred | mtype(Targettype) | mfunc

• mclause and mpred describe meta-structures based on predicate declarations
• mtype(TargetType) and mfunc describe meta-structures based on type definitions

There are sub-kind relationships like

:- subtype meta((X of mclause)) < meta((X of mpred)). % X is a meta-construct variable

The special type goal can be used as a non-meta type in subtype relationships and is as a meta-type identical with meta((trmFull of mpred)).

:- pred assert(meta((trmFull of mclause))).
%              ^^^^^^^^^^^^^^^^^^^^^^^^^^
%                        clause

:- pred retract(meta((trmFull of mclause))).
%               ^^^^^^^^^^^^^^^^^^^^^^^^^^
%                         clause

:- pred retractall(meta((trmFull of mpred))).
%                  ^^^^^^^^^^^^^^^^^^^^^^^^
%                            head

:- pred map(meta((trmName(@T1,@T2) of mpred)), list(T1),list(T2)).
%           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
%                       p: T1 × T2

:- pred sort(meta((trmName(@T,@T) of mpred)) , list(T),list(T)).
%            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
%                        p: T1 × T2

:- pred foldl(meta((trmName(@T1,@T,@T1) of mpred)) , T1,list(T),@T2) with T1 =< T2.
%             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
%                        p: T1 × T × T1

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