private void WritePrefixOperatorNode(ComposedTokenStream tokenStream, TexExpressionNode node,
ComposerState state)
{
if (node.Children.Count >= 1)
{
tokenStream.Write(TexToken.FromSymbol(node.Symbol));
foreach (var argNode in node.Arguments)
{
if (argNode.Children.Count != 1)
{
throw new TexComposerException(argNode, string.Format(
errorMessageUnexpectedNumberOfChildren, argNode.Symbol, argNode.Children.Count));
}
tokenStream.Write(TexToken.FromSymbol(argNode.Symbol));
WriteNode(tokenStream, argNode.Children[0], state);
}
tokenStream.Write(TexToken.FromSymbol(TexSymbolKind.Space));
foreach (var childNode in node.Children)
{
WriteNode(tokenStream, childNode, state);
}
}
else
{
throw new TexComposerException(node, string.Format(
errorMessageUnexpectedNumberOfChildren, node.Symbol, node.Children.Count));
}
}
private int GetOperatorPrecedence(TexExpressionNode node)
{
// Higher value means higher precedence.
switch (node.Symbol)
{
case TexSymbolKind.Plus:
case TexSymbolKind.Minus:
case TexSymbolKind.PlusMinus:
case TexSymbolKind.MinusPlus:
if (node.Children.Count == 1)
{
return(3);
}
return(2);
case TexSymbolKind.Star:
case TexSymbolKind.Dot:
case TexSymbolKind.Cross:
case TexSymbolKind.Divide:
case TexSymbolKind.Fraction:
case TexSymbolKind.InlineModulo:
return(4);
case TexSymbolKind.RaiseToIndex:
case TexSymbolKind.LowerToIndex:
return(5);
default:
if (node.Symbol.IsRelationOperator())
{
return(1);
}
return(-1);
}
}
private static TexExpressionNode FromInfixOperatorParseNode(ParseNode parseNode)
{
if (parseNode.Children.Count == 1)
{
return(FromParseTree(parseNode.Children[0]));
}
else if (parseNode.Children.Count == 3)
{
var node = new TexExpressionNode(parseNode.Children[1].Token.Symbol);
node.Children.Add(FromParseTree(parseNode.Children[0]));
node.Children.Add(FromParseTree(parseNode.Children[2]));
// If node is root of sub-expression and operator is left-recursive, then convert sub-tree from right
// recursive to left recursive.
if (!parseNode.IsSubExpression && node.Symbol.IsLtrInfixOperator())
{
return(ConvertTreeToLeftRecursive(node, parseNode));
}
else
{
return(node);
}
}
throw new TexExpressionTreeBuilderException(parseNode, string.Format(
errorMessageUnexpectedNumberOfChildren, parseNode.Kind, parseNode.Children.Count));
}
private static IEnumerable <TexExpressionNode> FromPrefixOperatorIndicesParseNode(ParseNode parseNode)
{
TexExpressionNode indexNode = null;
if (parseNode.Children.Count == 0)
{
yield break;
}
else if (parseNode.Children.Count == 2)
{
indexNode = new TexExpressionNode(parseNode.Children[0].Token.Symbol);
indexNode.Children.Add(FromParseTree(parseNode.Children[1]));
yield return(indexNode);
yield break;
}
else if (parseNode.Children.Count == 4)
{
indexNode = new TexExpressionNode(parseNode.Children[0].Token.Symbol);
indexNode.Children.Add(FromParseTree(parseNode.Children[1]));
yield return(indexNode);
indexNode = new TexExpressionNode(parseNode.Children[2].Token.Symbol);
indexNode.Children.Add(FromParseTree(parseNode.Children[3]));
yield return(indexNode);
yield break;
}
throw new TexExpressionTreeBuilderException(parseNode, string.Format(
errorMessageUnexpectedNumberOfChildren, parseNode.Kind, parseNode.Children.Count));
}
private void WriteBracketedFunction(ComposedTokenStream tokenStream, TexExpressionNode node,
ComposerState state)
{
if (node.Children.Count >= 1)
{
tokenStream.Write(TexToken.FromSymbol(node.Symbol));
foreach (var argNode in node.Arguments)
{
tokenStream.Write(TexToken.FromSymbol(TexSymbolKind.SquareBracketOpen));
state.IsParentNodeGroupOpen = true;
WriteNode(tokenStream, argNode, state);
tokenStream.Write(TexToken.FromSymbol(TexSymbolKind.SquareBracketClose));
}
foreach (var childNode in node.Children)
{
tokenStream.Write(TexToken.FromSymbol(TexSymbolKind.GroupOpen));
state.IsParentNodeGroupOpen = true;
WriteNode(tokenStream, childNode, state);
tokenStream.Write(TexToken.FromSymbol(TexSymbolKind.GroupClose));
}
}
else
{
throw new TexComposerException(node, string.Format(
errorMessageUnexpectedNumberOfChildren, node.Symbol, node.Children.Count));
}
}
public TokenStream Write(TexExpressionNode node)
{
using (var tokenStream = new ComposedTokenStream())
{
WriteNode(tokenStream, node, new ComposerState());
return(tokenStream);
}
}
private bool IsRightMostNode(TexExpressionNode node)
{
if (node.Parent == null)
{
return(true);
}
return(node.Parent.Children.IndexOf(node) == node.Parent.Children.Count &&
IsRightMostNode(node.Parent));
}
private static TexExpressionNode ConvertTreeToLeftRecursive(TexExpressionNode node, ParseNode parseNode)
{
Debug.Assert(node.Children.Count == 2);
Debug.Assert(parseNode.Children.Count == 3);
if (!parseNode.Children[2].IsSubExpression)
{
return(node);
}
var secondOperandNode = node.Children[1];
node.Children[1] = secondOperandNode.Children[0];
secondOperandNode.Children[0] = node;
return(ConvertTreeToLeftRecursive(secondOperandNode, parseNode.Children[2]));
}
private void WritePostfixOperatorNode(ComposedTokenStream tokenStream, TexExpressionNode node,
ComposerState state)
{
if (node.Children.Count >= 1)
{
foreach (var childNode in node.Children)
{
WriteNode(tokenStream, childNode, state);
}
tokenStream.Write(TexToken.FromSymbol(node.Symbol));
}
else
{
throw new TexComposerException(node, string.Format(
errorMessageUnexpectedNumberOfChildren, node.Symbol, node.Children.Count));
}
}
public bool Equals(TexExpressionNode tree)
{
if (!this.Symbol.Equals(tree.Symbol))
{
return(false);
}
if (this.Value != null && !this.Value.Equals(tree.Value))
{
return(false);
}
if (!this.Children.Count.Equals(tree.Children.Count))
{
return(false);
}
for (int i = 0; i < tree.Children.Count; i++)
{
if (!this.Children[i].Equals(tree.Children[i]))
{
return(false);
}
}
return(true);
}
private void WriteValueNode(ComposedTokenStream tokenStream, TexExpressionNode node,
ComposerState state)
{
tokenStream.Write(TexToken.FromValue(node.Symbol, node.Value));
}
private void WriteInfixOperatorNode(ComposedTokenStream tokenStream, TexExpressionNode node,
ComposerState state)
{
if (node.Children.Count == 1)
{
// Node is actually term prefix.
tokenStream.Write(TexToken.FromSymbol(node.Symbol));
WriteNode(tokenStream, node.Children[0], state);
}
else if (node.Children.Count == 2)
{
WriteNode(tokenStream, node.Children[0], state);
bool writeOpSymbol = true;
var padSymbol = (this.PadPlusAndMinusSigns && node.Symbol.IsPlusOrMinusOperator()) ||
node.Symbol.IsLongOperator();
if (node.Symbol == TexSymbolKind.Dot)
{
var checkNode = node.Children[1];
while (checkNode.Symbol == TexSymbolKind.Dot || checkNode.Symbol == TexSymbolKind.RaiseToIndex ||
checkNode.Symbol == TexSymbolKind.LowerToIndex)
{
checkNode = checkNode.Children[0];
}
// If terms can be multipled implicitly, do not write operator token.
switch (checkNode.Symbol)
{
case TexSymbolKind.Number:
case TexSymbolKind.Text:
break;
default:
if (checkNode.Children.Count <= 1)
{
writeOpSymbol = false;
padSymbol = false;
}
break;
}
}
if (padSymbol)
{
tokenStream.Write(TexToken.FromSymbol(TexSymbolKind.Space));
}
if (writeOpSymbol)
{
tokenStream.Write(TexToken.FromSymbol(node.Symbol));
}
if (padSymbol)
{
tokenStream.Write(TexToken.FromSymbol(TexSymbolKind.Space));
}
WriteNode(tokenStream, node.Children[1], state);
}
else
{
throw new TexComposerException(node, string.Format(
errorMessageUnexpectedNumberOfChildren, node.Symbol, node.Children.Count));
}
}
public static TokenStream CreateTokenStream(this TexExpressionNode tree)
{
var texComposer = new TexComposer();
return(texComposer.Write(tree));
}
private static TexExpressionNode FromPostfixOperatorIndicesParseNode(ParseNode parseNode,
ParseNode childParseNode)
{
TexExpressionNode firstIndexNode = null;
TexExpressionNode secondIndexNode = null;
if (parseNode.Children.Count == 0)
{
return(FromParseTree(childParseNode));
}
else if (parseNode.Children.Count == 2)
{
firstIndexNode = new TexExpressionNode(parseNode.Children[0].Token.Symbol);
}
else if (parseNode.Children.Count == 4)
{
firstIndexNode = new TexExpressionNode(parseNode.Children[0].Token.Symbol);
secondIndexNode = new TexExpressionNode(parseNode.Children[2].Token.Symbol);
}
else
{
throw new TexExpressionTreeBuilderException(parseNode, string.Format(
errorMessageUnexpectedNumberOfChildren, parseNode.Kind, parseNode.Children.Count));
}
Debug.Assert(firstIndexNode == null || firstIndexNode.Symbol == TexSymbolKind.RaiseToIndex ||
firstIndexNode.Symbol == TexSymbolKind.LowerToIndex,
"First index node is not RaiseToIndex or LowerToIndex.");
Debug.Assert(secondIndexNode == null || secondIndexNode.Symbol == TexSymbolKind.RaiseToIndex ||
secondIndexNode.Symbol == TexSymbolKind.LowerToIndex,
"Second index node is not RaiseToIndex or LowerToIndex.");
TexExpressionNode outerIndexNode;
TexExpressionNode innerIndexNode;
if (secondIndexNode == null)
{
outerIndexNode = firstIndexNode;
innerIndexNode = firstIndexNode;
}
else
{
// Use raised index as outer exprNode.
if (firstIndexNode.Symbol == TexSymbolKind.RaiseToIndex)
{
outerIndexNode = firstIndexNode;
innerIndexNode = secondIndexNode;
}
else
{
outerIndexNode = secondIndexNode;
innerIndexNode = firstIndexNode;
}
outerIndexNode.Children.Add(innerIndexNode);
}
// Add child nodes, and then nodes for indices.
innerIndexNode.Children.Add(FromParseTree(childParseNode));
firstIndexNode.Children.Add(FromParseTree(parseNode.Children[1]));
if (secondIndexNode != null)
{
secondIndexNode.Children.Add(FromParseTree(parseNode.Children[3]));
}
return(outerIndexNode);
}
public TexComposerException(TexExpressionNode node, string message)
: base(message)
{
this.Node = node;
}
public TexComposerException(TexExpressionNode node, ICollection <TexSymbolKind> expectedSymbolKinds)
: this(node, string.Format(errorMessageInvalidSymbol,
string.Join(", ", expectedSymbolKinds.Select(tokenKind => tokenKind.ToString()).ToArray())))
{
}
private void WriteNode(ComposedTokenStream tokenStream, TexExpressionNode node, ComposerState state)
{
var openBracketSymbol = TexSymbolKind.Null;
var closeBracketSymbol = TexSymbolKind.Null;
if ((node.Symbol.IsBinaryOperator() || node.Symbol.IsRelationOperator()) &&
!node.Symbol.IsRaiseOrLowerOperator())
{
// Check if current operator needs brackets because it has lower precedence than parent operator.
if (node.Parent != null && !node.Parent.Symbol.IsRaiseOrLowerOperator())
{
var nodePrecedence = GetOperatorPrecedence(node);
var parentNodePrecedence = GetOperatorPrecedence(node.Parent);
if (nodePrecedence != -1 && parentNodePrecedence != -1 &&
nodePrecedence < parentNodePrecedence ||
(nodePrecedence == parentNodePrecedence &&
(node.Parent.Children.IndexOf(node) == 0 ^ node.Parent.Symbol.IsLeftAssociativeOperator())))
{
openBracketSymbol = TexSymbolKind.RoundBracketOpen;
closeBracketSymbol = TexSymbolKind.RoundBracketClose;
}
}
}
else if (node.Symbol.IsFunctionOperator() || node.Symbol.IsBigOperator())
{
openBracketSymbol = TexSymbolKind.GroupOpen;
closeBracketSymbol = TexSymbolKind.GroupClose;
}
if (openBracketSymbol == TexSymbolKind.Null)
{
if (node.Parent != null)
{
// If any descendant node has more than one child, then group is needed.
bool needGroup = false;
var curNode = node;
while (curNode.Children.Count >= 1)
{
if (curNode.Children.Count > 1)
{
needGroup = true;
break;
}
curNode = curNode.Children[0];
}
if (needGroup)
{
switch (node.Parent.Symbol)
{
case TexSymbolKind.LowerToIndex:
case TexSymbolKind.RaiseToIndex:
openBracketSymbol = TexSymbolKind.GroupOpen;
closeBracketSymbol = TexSymbolKind.GroupClose;
break;
case TexSymbolKind.Factorial:
openBracketSymbol = TexSymbolKind.GroupOpen;
closeBracketSymbol = TexSymbolKind.GroupClose;
break;
}
}
}
}
if (IsRightMostNode(node))
{
// No need to write brackets, since current operator will be written last.
state.IsParentNodeGroupOpen = false;
openBracketSymbol = TexSymbolKind.Null;
closeBracketSymbol = TexSymbolKind.Null;
}
else if (!state.IsParentNodeGroupOpen && openBracketSymbol == TexSymbolKind.GroupOpen)
{
// Do not directly nest group brackets.
state.IsParentNodeGroupOpen = true;
}
if (openBracketSymbol != TexSymbolKind.Null)
{
tokenStream.Write(TexToken.FromSymbol(openBracketSymbol));
}
if (node.Symbol.IsBinaryOperator() || node.Symbol.IsRelationOperator())
{
WriteInfixOperatorNode(tokenStream, node, state);
}
else if (node.Symbol.IsBracketedFunction())
{
WriteBracketedFunction(tokenStream, node, state);
}
else if (node.Symbol.IsFunctionOperator() || node.Symbol.IsBigOperator())
{
WritePrefixOperatorNode(tokenStream, node, state);
}
else if (node.Symbol.IsPostfixOperator())
{
WritePostfixOperatorNode(tokenStream, node, state);
}
else if (node.Symbol.IsValue())
{
WriteValueNode(tokenStream, node, state);
}
else
{
throw new TexComposerException(node,
"Unrecognised node symbol.");
}
if (closeBracketSymbol != TexSymbolKind.Null)
{
tokenStream.Write(TexToken.FromSymbol(closeBracketSymbol));
}
}
public static string CreateText(this TexExpressionNode tree)
{
return(CreateText(CreateTokenStream(tree)));
}