| # Mode Statements | |
| * In the following, | |
| test_types_cases(2,`[[n,function],[[v,a],[v,b],[v,c]]]`, | |
| `[[[n,function],[[t,number],[t,string],[t,predicatename]]]]`, | |
| `[[[n,function],[output,output,output]]]`, | |
| [ | |
| `[[n,function],[[v,a],[v,b],[v,c]],":-",[[[n,=],[[v,a],1]],[[n,=],[[v,b],"a"]],[[n,=],[[v,c],[n,a]]]]]` | |
| ], | |
| `[[[[v,a], 1],[[v,b], "a"],[[v,c], [n,a]]]]`). | |
| * `[[[n,function],[output,output,output]]]`, is the mode statement, which must follow the type statement (although these are optional). The Mode Statement specifies whether each of the variables takes input or gives output. | |
| # Functional List Prolog (FLP) | |
| * List Prolog has an optional functional mode. In FLP, function calls may be passed as variables and functions may have strong types. | |
| * Functional algorithms may be recursive (see test 7 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: | |