| # Type Statements | |
| * Functions may have strong types, which check inputted values when calling a function and check all values when exiting a function. So far, any type statement with the name and arity of the function may match data for a call to that function. | |
| * The user may optionally enter types after the query. The following type statement tests number, string and predicate name types. | |
| * Note: Mode statements, described in the next section, are required after Type Statements. | |
| * Types with lists (0-infinite repeats of type statements) are written inside {}. There may be nested curly brackets. | |
| * Type Statements may be recursive (see test 23 in <a href="https://github.com/luciangreen/listprologinterpreter/blob/master/lpiverify4_types.pl">lpiverify4_types.pl</a>), i.e. they may repeat until triggering the base case: | |
| test_types_cases(23,`[[n,connect_cliques],[[["a",1],[1,2],[2,"b"]],[["a",3],[3,4],[4,"b"]],[v,output]]]`, | |
| `[ | |
| [[n,connect_cliques],[[t,list2],[t,list2],[t,list2]]], | |
| [[t,item],[[t,number]]], | |
| [[t,item],[[t,string]]], | |
| [[t,list2],[{[t,item]}]], | |
| [[t,list2],[{[t,list2]}]] | |
| ]`, | |
| `[[[n,connect_cliques],[input,input,output]]]`, | |
| `[[[n,connect_cliques],[[v,a],[v,b],[v,c]],":-",[[[n,append],[[v,a],[v,b],[v,c]]]]]]`, | |
| `[[[[v,output],[["a",1],[1,2],[2,"b"],["a",3],[3,4],[4,"b"]]]]]`). | |