42 lines
1.8 KiB
C#
42 lines
1.8 KiB
C#
using System.Collections.Generic;
|
|
using System.Linq;
|
|
using Immutable;
|
|
using static Global;
|
|
|
|
public class Evaluator {
|
|
public static string Evaluate(Ast.AstNode source)
|
|
// => Log(source.Str(), ()
|
|
=> source.Match(
|
|
Operator: o => o.Item1.semantics.Match(
|
|
// The wrapper around the whole program:
|
|
Program: () => {
|
|
if (o.Item2.Count() != 3) {
|
|
throw new RuntimeErrorException("The Program wrapper should contain two parts: StartOfInput, prog and EndOfInput");
|
|
}
|
|
// TODO: check that the last token is indeed Program
|
|
return Evaluate(o.Item2.ElementAt(1));
|
|
},
|
|
LiteralInt: () =>
|
|
o.Item2
|
|
.Single()
|
|
.ElseThrow(
|
|
new RuntimeErrorException("LiteralInt should contain a single lexeme"))
|
|
.AsTerminal
|
|
.ElseThrow(
|
|
new RuntimeErrorException("LiteralInt's contents should be a lexeme"))
|
|
.lexeme,
|
|
LiteralString: () => {
|
|
if (o.Item2.Count() != 3) {
|
|
throw new RuntimeErrorException("LiteralString should contain three lexemes: OpenString, String and CloseString");
|
|
}
|
|
// TODO: check that the open & close are indeed that
|
|
return o.Item2.ElementAt(1)
|
|
.AsTerminal.ElseThrow(
|
|
new RuntimeErrorException("LiteralInt's contents should be a lexeme"))
|
|
.lexeme;
|
|
},
|
|
Unsupported: () => throw new RuntimeErrorException($"Unsupported opeartor {o}, sorry.")),
|
|
Terminal: t => t.lexeme/*TODO*/);
|
|
}
|
|
|
|
// Note: for typeclass resolution, ask that functions have their parameters and return types annotated. This annotation is added to the values at run-time, which allows to dispatch based on the annotation rather than on the actual value. |