stgsharp/StgSharp.Script/Express/ExpSyntaxAnalyzer.OperatorParser.cs

//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="ExpSyntaxAnalyzer.OperatorParser"
// Project: StgSharp
// AuthorGroup: Nitload Space
// Copyright (c) Nitload Space. All rights reserved.
//     
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using ExpKeyword = StgSharp.Script.Express.ExpressCompile.Keyword;

namespace StgSharp.Script.Express
{
    public partial class ExpSyntaxAnalyzer
    {

        public int CompareOperatorPrecedence(Token left, Token right)
        {
            ExpressCompile.TryGetOperatorPrecedence(left.Value, out int leftPrecedence);
            ExpressCompile.TryGetOperatorPrecedence(right.Value, out int rightPrecedence);
            return leftPrecedence - rightPrecedence;
        }

        public bool TryGenerateUnaryNode(Token t, out ExpSyntaxNode node)
        {
            ExpSyntaxNode operand = GetNextOperandCache();
            switch (t.Value)
            {
                case ExpKeyword.UnaryPlus:
                    node = ExpUnaryOperatorNode.UnaryPlus(t, operand);
                    return true;
                case ExpKeyword.UnaryMinus:
                    node = ExpUnaryOperatorNode.UnaryMinus(t, operand);
                    return true;
                case ExpKeyword.Not:
                    node = ExpUnaryOperatorNode.UnaryNot(t, operand);
                    return true;
                default:
                    node = ExpSyntaxNode.Empty;
                    return false;
            }
        }

        /// <summary>
        ///   WARNING: This method cannot process INDEXOF, FUNCTION CALLING, LOOP and any ENDING
        ///   SYMBOLS.
        /// </summary>
        private ExpSyntaxNode ConvertAndPushOneOperator(Token op)
        {
            switch (op.Flag)
            {
                case TokenFlag.Symbol_Unary:
                    TryGenerateUnaryNode(op, out ExpSyntaxNode? node);
                    _cache.PushOperand(node);
                    return node;
                case TokenFlag.Symbol_Binary:
                    TryGenerateBinaryNode(op, out node);
                    _cache.PushOperand(node);
                    return node;
                case TokenFlag.Member:
                    if (_context.TryGetFunction(op.Value, out ExpFunctionSource? f))
                    {
                        if (!_cache.PopOperand(out Token t, out ExpSyntaxNode? p))
                        {
                            node = ExpFunctionCallingNode.CallFunction(op, f, p);
                            return node;
                        } else
                        {
                            throw new ExpCompileException(
                                t,
                                "An ExpNode for function calling is needed, but a token was popped");
                        }
                    } else if (_context.TryGetProcedure(op.Value, out ExpProcedureSource? p))
                    {
                        if (!_cache.PopOperand(out Token t, out ExpSyntaxNode? param))
                        {
                            node = ExpProcedureCallingNode.CallProcedure(op, p, param);
                            return node;
                        } else
                        {
                            throw new ExpCompileException(
                                t,
                                "An ExpNode for function calling is needed, but a token was popped");
                        }
                    } else if (ExpSchema.BuiltinSchema.TryGetFunction(op.Value, out f))
                    {
                        if (!_cache.PopOperand(out Token t, out ExpSyntaxNode? param))
                        {
                            node = ExpFunctionCallingNode.CallFunction(op, f, param);
                            return node;
                        } else
                        {
                            throw new ExpCompileException(
                                t,
                                "An ExpNode for function calling is needed, but a token was popped");
                        }
                    } else
                    {
                        throw new NotImplementedException();

                        // uncertain case here
                    }
                default:
                    throw new NotImplementedException();
            }
        }

        private bool TryGenerateBinaryNode(Token t, out ExpSyntaxNode node)
        {
            ExpSyntaxNode right = GetNextOperandCache();
            ExpSyntaxNode left = GetNextOperandCache();
            switch (t.Value)
            {
                case ExpKeyword.Add:
                    node = ExpBinaryOperatorNode.Add(t, left, right);
                    return true;
                case ExpKeyword.Sub:
                    node = ExpBinaryOperatorNode.Sub(t, left, right);
                    return true;
                case ExpKeyword.Mul:
                    node = ExpBinaryOperatorNode.Mul(t, left, right);
                    return true;
                case ExpKeyword.Div:
                    node = ExpBinaryOperatorNode.Div(t, left, right);
                    return true;
                case ExpKeyword.Equal:
                    node = ExpBinaryOperatorNode.EqualTo(t, left, right);
                    return true;
                case ExpKeyword.NotEqual:
                    node = ExpBinaryOperatorNode.NotEqualTo(t, left, right);
                    return true;
                case ExpKeyword.GreaterThan:
                    node = ExpBinaryOperatorNode.GreaterThan(t, left, right);
                    return true;
                case ExpKeyword.LessThan:
                    node = ExpBinaryOperatorNode.LessThan(t, left, right);
                    return true;
                case ExpKeyword.Assignment:
                    node = ExpBinaryOperatorNode.Assign(t, left, right);
                    return true;
                case ExpKeyword.InstanceEqual:
                    node = ExpBinaryOperatorNode.CompareInstanceEqual(t, left, right);
                    return true;
                case ExpKeyword.InstanceNotEqual:
                    node = ExpBinaryOperatorNode.CompareInstanceNotEqual(t, left, right);
                    return true;
                default:
                    node = ExpSyntaxNode.Empty;
                    return false;
            }
        }

    }
}