Jim/MathsEngine
1
0
Fork 0
mirror of https://github.com/0xJ1M/MathsEngine.git synced 2026-06-05 02:00:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

Feature/basic evaluator (#2)

Browse Source 
* Refactor

* Updated TreeNode system to use abstract base class and inheritence

* Updated unit test coverage

* Improved code coverage
This commit is contained in:
0xJ1M
2023-09-08 17:53:13 +01:00
committed by GitHub
parent 9c5bf4c0d5
commit a555a131af
9 changed files with 180 additions and 392 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
MathEngine/EngineTests/EngineTests.csproj
View File

@@ -1,13 +1,19 @@
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net6.0</TargetFramework>
<TargetFramework>net7.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
<IsPackable>false</IsPackable>
<EnforceCodeStyleInBuild>True</EnforceCodeStyleInBuild>
</PropertyGroup>
<ItemGroup>
<Compile Remove="Parser Tests\TreeNodeTests.cs" />
</ItemGroup>
<ItemGroup>
<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
<PackageReference Include="MSTest.TestAdapter" Version="2.2.8" />

28
MathEngine/EngineTests/Parser Tests/ExpressionTreeTests.cs
View File

@@ -16,15 +16,8 @@ namespace EngineTests
public void TestExpressionTreeSimpleExpression()
{
string testExp = "3+4";
TreeNode exptectedTree = new(Token.Plus);
Token tokfour = new("4", Token.Type.Numeric, Token.NumericType.Decimal, 0);
Token tokthree = new("3", Token.Type.Numeric, Token.NumericType.Decimal, 0);
TreeNode four = new(tokfour);
TreeNode three = new(tokthree);
exptectedTree.AddChildNode(four);
exptectedTree.AddChildNode(three);
ExpressionTree returnedTree = new(testExp);
Assert.IsTrue(returnedTree.Equals(exptectedTree));
Assert.IsTrue(returnedTree.ToString() == "7");
}
/// <summary>
@@ -34,11 +27,8 @@ namespace EngineTests
public void TestExpressionTreeSimpleExpressionEvaluation()
{
string testExp = "3+4*7";
Token tok31 = new("31", Token.Type.Numeric, Token.NumericType.Decimal, 0);
TreeNode exptectedTree = new(tok31);
ExpressionTree returnedTree = new(testExp);
ExpressionTree? evaluatedTree = returnedTree.Evaluate();
Assert.IsTrue(evaluatedTree.Equals(exptectedTree));
Assert.IsTrue(returnedTree.ToString() == "31");
}
/// <summary>
@@ -49,11 +39,17 @@ namespace EngineTests
{
string testExp = "3+4*7-8/7";
decimal testValue = decimal.Divide(209 , 7);
Token tok31 = new(testValue.ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0);
TreeNode exptectedTree = new(tok31);
ExpressionTree returnedTree = new(testExp);
ExpressionTree? evaluatedTree = returnedTree.Evaluate();
Assert.IsTrue(evaluatedTree.Equals(exptectedTree));
Assert.IsTrue(returnedTree.ToString() == testValue.ToString());
}
[TestMethod]
public void TestExpressionTreeGetHashCodeReturnsHashCode()
{
string testExp = "1+1";
ExpressionTree returnedTree1 = new(testExp);
int hash = returnedTree1.GetHashCode();
Assert.IsInstanceOfType(hash, typeof(int));
}
}
}

65
MathEngine/EngineTests/Parser Tests/TokenIserTests.cs
View File

@@ -1,65 +0,0 @@
using MathEngine.Parser.Tokeniser;
namespace EngineTests
{
/// <summary>
/// Class for testing the Tokeniser
/// </summary>
[TestClass]
public class TokeniserTests
{
/// <summary>
/// Test the tokeniser on a basic string
/// </summary>
[TestMethod]
public void TestTokeniseBasicString()
{
//Arrange
string testString = "1+1";
Token one = new("1", Token.Type.Numeric, Token.NumericType.Decimal, 0);
List<Token> expectedValue = new()
{
one,
Token.Plus,
one
};
//Act
List<Token> returnedValue = Tokeniser.Tokenise(testString);
//Assert
Assert.IsTrue(expectedValue.SequenceEqual(returnedValue));
}
/// <summary>
/// Test the tokeniser on a basic string, but with significant ammounts of whitespace
/// </summary>
[TestMethod]
public void TestTokeniseBasicStringWithWhiteSpace()
{
//Arrange
string testString = " 1 + 1 ";
Token one = new("1", Token.Type.Numeric, Token.NumericType.Decimal, 0);
List<Token> expectedValue = new()
{
one,
Token.Plus,
one
};
//Act
List<Token> returnedValue = Tokeniser.Tokenise(testString);
//Assert
Assert.IsTrue(expectedValue.SequenceEqual(returnedValue));
}
/// <summary>
/// Test the tokeniser on a string which contains a number which is not formatted correctly
/// </summary>
[TestMethod]
public void TestTokeniseStringWithInvalidNumbr()
{
//Arrange
string testString = "1+11.2.5";
//Act and Assert
Assert.ThrowsException<Exception>(() => Tokeniser.Tokenise(testString));
}
}
}

74
MathEngine/MathEngine/Evaluator/Evaluator.cs Normal file
View File

@@ -0,0 +1,74 @@
using MathEngine.Parser.Parser;
using MathEngine.Parser.Tokeniser;
namespace MathEngine.Parser.Evaluator
{
/// <summary>
/// Class that evaluate TreeNodes
/// </summary>
internal class Evaluator
{
/*public static TreeNode? Evaluate(TreeNode rootNode)
{
if (rootNode == null)
{
return null;
}
else // To evaluate we go anti-clockwise around the tree
{
TreeNode? Root, LeftBranch, RightBranch;
if (rootNode.NodeValue.Token_Type == Token.Type.Numeric)
return rootNode;
else
{ //For now these can't be null, this will need to be updated in the future
LeftBranch = Evaluate_Tree_Branch(rootNode.GetChildNode(0));
RightBranch = Evaluate_Tree_Branch(rootNode.GetChildNode(1));
Root = Evaluate_Operator(rootNode.NodeValue, LeftBranch, RightBranch);
return Root;
}
}
}
/// <summary>
/// Evaluates branches of a given tree
/// </summary>
/// <param name="Branch">The TreeNode branch to evaluate</param>
/// <returns>Returns the Evaluation of the Branch</returns>
private static TreeNode Evaluate_Tree_Branch(TreeNode Branch)
{
TreeNode Root, LeftBranch, RightBranch;
if (Branch.NodeValue.Token_Type == Token.Type.Numeric)
return Branch;
else
{
LeftBranch = Evaluate_Tree_Branch(Branch.GetChildNode(0));
RightBranch = Evaluate_Tree_Branch(Branch.GetChildNode(1));
// We finally combine the computed branches with the operator that links them and return the result
Root = Evaluate_Operator(Branch.NodeValue, LeftBranch, RightBranch);
return Root;
}
}
/// <summary>
/// Evlautes a binary node where the root node is an operator and given two branches the left and the right
/// </summary>
/// <param name="Operator_Token"></param>
/// <param name="Left_Branch"></param>
/// <param name="Right_Branch"></param>
/// <returns>Returns the evaluated value of the operator as a TreeNode</returns>
private static TreeNode Evaluate_Operator(Token Operator_Token, TreeNode Left_Branch, TreeNode Right_Branch)
{
decimal lhs = decimal.Parse(Left_Branch.NodeValue.TokenValue);
decimal rhs = decimal.Parse(Right_Branch.NodeValue.TokenValue);
return Operator_Token.Token_Type switch
{
Token.Type.Addition => new TreeNode(new Token((lhs + rhs).ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0)),
Token.Type.Subtraction => new TreeNode(new Token((lhs - rhs).ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0)),
Token.Type.Multiplication => new TreeNode(new Token(((decimal)(lhs * rhs)).ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0)),
Token.Type.Division => new TreeNode(new Token(((decimal)(lhs / rhs)).ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0)),
_ => throw new Exception("Potentially invalid token?"),
};
}*/
}
}

7
MathEngine/MathEngine/MathEngine.csproj
View File

@@ -1,10 +1,15 @@
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net6.0</TargetFramework>
<TargetFramework>net7.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
<EnforceCodeStyleInBuild>True</EnforceCodeStyleInBuild>
</PropertyGroup>
<ItemGroup>
<Compile Remove="Parser\Nodes\TreeNode.cs" />
</ItemGroup>
<ItemGroup>
<AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
<_Parameter1>EngineTests</_Parameter1>

162
MathEngine/MathEngine/Parser/Parser/ExpressionTree.cs
View File

@@ -1,5 +1,4 @@
using System.Collections.Generic;
using MathEngine.Parser.Tokeniser;
using MathEngine.Parser.Tokeniser;
namespace MathEngine.Parser.Parser
{
/// <summary>
@@ -10,7 +9,8 @@ namespace MathEngine.Parser.Parser
/// <summary>
/// The root node of the expression tree;
/// </summary>
private readonly TreeNode rootNode;
private readonly BaseNode rootNode;
private readonly BaseNode? evaluated_expression;
/// <summary>
/// Initialises a new instance of the MathEngine.Parser.Parser.Node class with a given Token
@@ -21,161 +21,34 @@ namespace MathEngine.Parser.Parser
{
List<Token> tokens = Tokeniser.Tokeniser.Tokenise(Expression);
Stack<Token> rpnForm = Parser.Parse(tokens);
rootNode = GenerateExpressionTree(rpnForm);
rootNode = TreeGenerator.TreeFromRPN(rpnForm);
evaluated_expression = rootNode.Evaluate();
}
private ExpressionTree(TreeNode rootNode)
private ExpressionTree(BaseNode rootNode)
{
this.rootNode = rootNode;
}
/// <summary>
/// Creates a binary TreeNode, that is a node with a root value and two children
/// </summary>
/// <param name="CurrentToken">The token to be the root node of the TreeNode</param>
/// <param name="LeftToken">TreeNode that is the left branch of the current node</param>
/// <param name="RightToken">TreeNode that is the right branch of the current node</param>
/// <returns>A TreeNode with CurrentToken as the root value and LeftBranch and RightBranch as Children</returns>
private static TreeNode CreateBinaryNode(Token CurrentToken, TreeNode LeftBranch, TreeNode RightBranch)
{
TreeNode root = new(CurrentToken);
root.AddChildNode(LeftBranch);
root.AddChildNode(RightBranch);
return root;
}
/// <summary>
/// Creates a unary TreeNode, that is a node with a root value and two children
/// </summary>
/// <param name="CurrentToken">The token to be the root node of the TreeNode</param>
/// <param name="LeftToken">TreeNode that is the child of the current node</param>
/// <returns>A TreeNode with CurrentToken as the root value and ChildNode as the sole child node</returns>
private static TreeNode CreateUnaryNode(Token CurrentToken, TreeNode ChildNode)
{
TreeNode root = new(CurrentToken);
root.AddChildNode(ChildNode);
return root;
}
/// <summary>
/// Generates the full expression tree given an RPN expression stack
/// </summary>
/// <param name="rpnExpression">RPN expression stack to generate an expression tree from</param>
/// <returns>An expression Tree that represents the Mathematical expression given by rpnExpression</returns>
private static TreeNode GenerateExpressionTree(Stack<Token> rpnExpression)
{
Stack<TreeNode> OutputStack = new(rpnExpression.Count);
TreeNode Node;
Token CurrentToken;
while (rpnExpression.Count != 0)
{
CurrentToken = rpnExpression.Pop();
switch (CurrentToken.Token_Type)
{
case Token.Type.Numeric:
Node = new TreeNode(CurrentToken);
OutputStack.Push(Node);
break;
// We need to preserve "Left handness" of the ExpressionTree
// i.e 7/8 gives a root node of / with Cnode(0) = 7 and Cnod(1) = 8 etc.
// This should preserve non commutativity
case Token.Type.Addition:
case Token.Type.Subtraction:
case Token.Type.Multiplication:
case Token.Type.Division:
case Token.Type.Exponentiation:
TreeNode Right = OutputStack.Pop();
TreeNode Left = OutputStack.Pop();
Node = CreateBinaryNode(CurrentToken, Left, Right);
OutputStack.Push(Node);
break;
case Token.Type.UnaryPlus:
case Token.Type.UnaryMinus:
Node = CreateUnaryNode(CurrentToken, OutputStack.Pop());
OutputStack.Push(Node);
break;
}
}
return OutputStack.Pop();
}
/// <summary>
/// Evaluates branches of a given tree
/// </summary>
/// <param name="Branch">The TreeNode branch to evaluate</param>
/// <returns>Returns the Evaluation of the Branch</returns>
private static TreeNode Evaluate_Tree_Branch(TreeNode Branch)
{
TreeNode Root, LeftBranch, RightBranch;
if (Branch.NodeValue.Token_Type == Token.Type.Numeric)
return Branch;
else
{
LeftBranch = Evaluate_Tree_Branch(Branch.GetChildNode(0));
RightBranch = Evaluate_Tree_Branch(Branch.GetChildNode(1));
// We finally combine the computed branches with the operator that links them and return the result
Root = Evaluate_Operator(Branch.NodeValue, LeftBranch, RightBranch);
return Root;
}
}
/// <summary>
/// Evlautes a binary node where the root node is an operator and given two branches the left and the right
/// </summary>
/// <param name="Operator_Token"></param>
/// <param name="Left_Branch"></param>
/// <param name="Right_Branch"></param>
/// <returns>Returns the evaluated value of the operator as a TreeNode</returns>
private static TreeNode Evaluate_Operator(Token Operator_Token, TreeNode Left_Branch, TreeNode Right_Branch)
{
decimal lhs = decimal.Parse(Left_Branch.NodeValue.TokenValue);
decimal rhs = decimal.Parse(Right_Branch.NodeValue.TokenValue);
return Operator_Token.Token_Type switch
{
Token.Type.Addition => new TreeNode(new Token((lhs + rhs).ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0)),
Token.Type.Subtraction => new TreeNode(new Token((lhs - rhs).ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0)),
Token.Type.Multiplication => new TreeNode(new Token(((decimal)(lhs * rhs)).ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0)),
Token.Type.Division => new TreeNode(new Token(((decimal)(lhs / rhs)).ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0)),
_ => throw new Exception("Potentially invalid token?"),
};
}
/// <summary>
/* /// <summary>
/// Evaluates the current instance of ExpressionTree
/// </summary>
/// <returns>Returns an update of the current instance which the expression Evaluated</returns>
public ExpressionTree? Evaluate()
public ExpressionTree Evaluate()
{
if (rootNode == null)
{
return null;
}
else // To evaluate we go anti-clockwise around the tree
{
TreeNode? Root, LeftBranch, RightBranch;
if (rootNode.NodeValue.Token_Type == Token.Type.Numeric)
return this;
else
{ //For now these can't be null, this will need to be updated in the future
LeftBranch = Evaluate_Tree_Branch(rootNode.GetChildNode(0));
RightBranch = Evaluate_Tree_Branch(rootNode.GetChildNode(1));
Root = Evaluate_Operator(rootNode.NodeValue, LeftBranch, RightBranch);
return new ExpressionTree(Root);
}
}
}
return new ExpressionTree(rootNode.Evaluate());
}*/
/// <summary>
/// <summary>
/// Returns a value indicating if the given object is equal to the current instance of ExpressionTree
/// </summary>
/// <param name="other">The object to compare to the current instance</param>
/// <returns>True if they are equal, False otherwise</returns>
public override bool Equals(object? other)
public override bool Equals(object? other)
{
if (other is TreeNode)
if (other is BaseNode)
{
ExpressionTree otherTree = new((TreeNode)other);
ExpressionTree otherTree = new((BaseNode)other);
return this.Equals(otherTree);
}
return false;
@@ -201,7 +74,12 @@ namespace MathEngine.Parser.Parser
public override int GetHashCode()
{
return System.HashCode.Combine(this.rootNode);
return System.HashCode.Combine(rootNode, evaluated_expression);
}
public override string ToString()
{
return evaluated_expression.ToString();
}
}
}

158
MathEngine/MathEngine/Parser/Parser/Node/TreeNode.cs
View File

@@ -1,158 +0,0 @@
using MathEngine.Parser.Tokeniser;
namespace MathEngine.Parser.Parser
{
/// <summary>
/// Represents a node in a Tree structure
/// </summary>
internal class TreeNode
{
private TreeNode? Parent;
private List<TreeNode>? Children;
private readonly Token Value;
/// <summary>
/// Initialises a new instance of the MathEngine.Parser.Parser.Node class with a given Token
/// </summary>
/// <param name="value">The token for the nodes value</param>
public TreeNode(Token value)
{
Parent = null;
Children = null;
Value = value;
}
/// <summary>
/// Returns the value of the node
/// </summary>
public Token NodeValue
{
get { return Value; }
}
/// <summary>
/// Returns the parent node of the current node, or null if it does not exist
/// </summary>
public TreeNode? ParentNode
{
get
{
if (Parent == null)
{
return null;
}
else
{
return Parent;
}
}
}
/// <summary>
/// Returns all of the child nodes of the current node, or null if it odes not exist
/// </summary>
public List<TreeNode>? GetChildrenNodes
{
get
{
if (Children == null)
{
return null;
}
else
{
return Children;
}
}
}
/// <summary>
/// Returns the child node specified by the index, if there are no children nodes or if the index is out of bounds than null is returned
/// </summary>
/// <param name="index">The index of the child node to get</param>
/// <returns>The ChildNode at the specified index, null if it is null or the index is out-of-bounds</returns>
public TreeNode? GetChildNode(int index)
{
if (Children == null)
{
return null;
}
if (index < 0 || index >= Children.Count)
{
return null;
}
return Children[index];
}
/// <summary>
/// Adds a child node to the current root node, if there are no children nodes a list is created
/// </summary>
/// <param name="Node">The value for the child node that is to be added</param>
public void AddChildNode(TreeNode Node)
{
if (Children == null)
{
Children = new()
{
Node
};
}
else
{
Children.Add(Node);
}
}
/// <summary>
/// Returns a value that indicates if the given object is equal to the current instance of TreeNode
/// </summary>
/// <param name="other">The object to compare to the current instance of TreeNode</param>
/// <returns>True if the object innstace is equal to the current ExpressionTree instance, False otherwise</returns>
public override bool Equals(object? other)
{
if (other is ExpressionTree)
{
return other.Equals(this);
}
return false;
}
/// <summary>
/// Returns a value that indicates if the given TreeNode instance is equal to another
/// </summary>
/// <param name="other">The TreeNode to check for equality</param>
/// <returns>True if they are equal, False otherwise</returns>
public bool Equals(TreeNode other)
{
if (this.Value != other.Value) //If the root values are not equal we are done
{
return false;
}
// otherwise,
if (this.Children != null && other.Children != null) // If both children are NOT null then we reursively check the child nodes
{
//Covered all nullable cases, we now need to recursively check the child nodes
if (Children.Count != other.Children.Count)
{
return false;
}
for (int childNodeIndex = 0; childNodeIndex < Children.Count; childNodeIndex++)
{
if (!Children[childNodeIndex].Equals(other.Children[childNodeIndex]))
{
return false;
}
}
return true;
}
else if (this.Children == null && other.Children == null) //Special case is if both children lists are null then the TreeNodes are equal
{
return true;
}
else // otherwise at least one is null and the other is not so they can't be equal
{
return false; // if both children are not null than at least one is null so they can't be equal
}
}
}
}

52
MathEngine/MathEngine/Parser/Parser/TreeGenerator.cs Normal file
View File

@@ -0,0 +1,52 @@
using MathEngine.Parser.Tokeniser;
namespace MathEngine.Parser.Parser
{
/// <summary>
/// Class for converting from RPN form to an expression tree
/// </summary>
internal class TreeGenerator
{
/// <summary>
/// Generates the full expression tree given an RPN expression stack
/// </summary>
/// <param name="rpnExpression">RPN expression stack to generate an expression tree from</param>
/// <returns>An expression Tree that represents the Mathematical expression given by rpnExpression</returns>
public static BaseNode TreeFromRPN(Stack<Token> rpnExpression)
{
Stack<BaseNode> OutputStack = new(rpnExpression.Count);
BaseNode Node;
Token CurrentToken;
while (rpnExpression.Count != 0)
{
CurrentToken = rpnExpression.Pop();
switch (CurrentToken.Token_Type)
{
case Token.Type.Numeric:
Node = NodeFactory.CreateNumericNode(CurrentToken);
OutputStack.Push(Node);
break;
// We need to preserve "Left handness" of the ExpressionTree
// i.e 7/8 gives a root node of / with Cnode(0) = 7 and Cnod(1) = 8 etc.
// This should preserve non commutativity
case Token.Type.Addition:
case Token.Type.Subtraction:
case Token.Type.Multiplication:
case Token.Type.Division:
case Token.Type.Exponentiation:
BaseNode Right = OutputStack.Pop();
BaseNode Left = OutputStack.Pop();
Node = NodeFactory.CreateBinaryNode(CurrentToken, Left, Right);
OutputStack.Push(Node);
break;
case Token.Type.UnaryPlus:
case Token.Type.UnaryMinus:
//Node = NodeFactory.CreateUnaryNode(CurrentToken, OutputStack.Pop());
//OutputStack.Push(Node);
break;
}
}
return OutputStack.Pop();
}
}
}

18
MathEngine/MathEngine/Parser/Tokeniser/Token.cs
View File

@@ -179,23 +179,23 @@
/// <returns>Returns true if the two Tokens are not equal and false otherwise</returns>
public static bool operator !=(Token X, Token Y)
{
if (X.TokenValue == Y.TokenValue)
if (X.TokenValue != Y.TokenValue)
{
return false;
return true;
}
if (X.TokenType == Y.TokenType)
if (X.TokenType != Y.TokenType)
{
return false;
return true;
}
if (X.NumericalType == Y.NumericalType)
if (X.NumericalType != Y.NumericalType)
{
return false;
return true;
}
if (X.Arity == Y.Arity)
if (X.Arity != Y.Arity)
{
return false;
return true;
}
return true;
return false;
}
/// <summary>