Upsilon/Upsilon/Evaluator/Evaluator.cs

using System;
using System.Linq;
using Upsilon.BaseTypes;
using Upsilon.BaseTypes.ScriptFunction;
using Upsilon.Binder;
using Upsilon.Evaluator.Debugging;
using Upsilon.Exceptions;
using Upsilon.Text;
using Upsilon.Utilities;
using Type = Upsilon.BaseTypes.Type;

namespace Upsilon.Evaluator
{
    internal class Evaluator
    {
        private readonly Script _script;
        private Diagnostics _diagnostics;
        internal EvaluationScope Scope { get; private set; }

        internal Evaluator(Diagnostics diagnostics, EvaluationScope parentScope, Script script)
        {
            _diagnostics = diagnostics;
            _script = script;
            Scope        = new EvaluationScope(parentScope);
        }

        private Evaluator(Script script)
        {
            _script = script;
        }

        internal static Evaluator CreateWithSetScope(Diagnostics diagnostics, EvaluationScope scope, Script script)
        {
            return new Evaluator(script) {_diagnostics = diagnostics, Scope = scope};
        }

        public ScriptType Evaluate(BoundScript e)
        {
            if (DebugSession.DebuggerAttached && !string.IsNullOrWhiteSpace(e.FileName))
            {
                var file = DebugSession.GetFileInfo(e.FileName);
                if (file != null)
                {
                    foreach (var breakpoint in file.Breakpoints)
                    {
                        var debugStatement = e.GetBottomStatementAtPosition(breakpoint.Line, breakpoint.Position);
                        debugStatement.HasBreakpoint = true;
                    }
                }
            }

            var evaluationState = new EvaluationState()
            {
                Script = _script
            };
            e.Evaluate(Scope, _diagnostics, ref evaluationState);
            if (evaluationState.ReturnValue != null)
                return evaluationState.ReturnValue;
            return evaluationState.LastValue;
        }

        public ScriptType Evaluate(BoundScript e, string functionName, object[] parameters)
        {
            if (!Scope.TryGet(functionName, out var statement) || statement.Type != Type.Function)
            {
                throw new ArgumentException(($"Function '{functionName}' could not be found"));
            }
            var function = (ScriptRuntimeFunction) statement;
            var option = function.GetValidOption(parameters);
            if (option == null)
            {
                if (parameters == null)
                {
                    throw new EvaluationException(_script.FileName,
                        $"No function found with name '{functionName}' and no parameters.",
                        e.Span);
                }
                throw new EvaluationException(_script.FileName,
                    $"No function found with name '{functionName}' and available parameters {string.Join(", ", parameters.Select(x => $"{x.GetType().Name}"))}",
                    e.Span);
            }
            var result = option.Run(_diagnostics, parameters?.Select(x => x.ToScriptType()).ToArray(), _script, Scope, new TextSpan());
            return result;
        }
    }
}