Everything you need to read and write Tln.
Then see Tln next to the language it modernizes in Prolog → Tln, and the capabilities Prolog never had in Beyond Prolog.
Hello, World The smallest useful Tln program finds something in your data and flags it. Here we flag any greeting record and greet it by name — Prolog on the left, Tln on the right: ISO Prolog (1995)% Facts loaded externally; shown here as plain facts: greeting(1, 'World'). hello(Id) :- greeting(Id, Name), format("Hello, ~w!~n", [Name]). Tlndetect "Hello, World" { for records where type == "greeting" flag matching items label "Hello, {attr.name}!" } Line by line: ...
Facts are loaded from external systems (see the mental model); .tln files contain blocks that reason over them. Values 42 3.14 // numbers "outpatient" // strings — always double-quoted true false // booleans 7 days 30 days 12 months 1 year // durations ["health", "cancellation"] [100, 200] // lists Operators > < >= <= == != ~= // comparison + - * / % // arithmetic and or not // logical in [ … ] not in [ … ] // membership contains starts_with ends_with older_than newer_than // string / temporal Selectors A selector picks which records a block runs over: ...