Inspecting the language

In the previous step we defined our greeting expression, a type consisting of two functions. We can now create a new language from this expression, appropriately called greet.

const greet = new Language("greet", greeting);

Krikata can automatically generate a grammar for greet in an approximate BNF notation.

const grammar = greet.grammar();
console.log(grammar.format());

l.greet:
 | <t.greeting> EOI

t.greeting:
 | "hi"   
 | "hello" <p.string>

We see our two expressions. First the language greet, which expects a greeting type followed by the special End-Of-Input, and second the greeting type itself, which matches either the string hi or the string hello followed by a primitive string.