public static ScriptExpression Rewrite(TemplateContext context, ScriptBinaryExpression binaryExpression)
{
Debug.Assert(ImplicitFunctionCallPrecedence < Parser.PrecedenceOfMultiply);
if (!HasImplicitBinaryExpression(binaryExpression))
{
return(binaryExpression);
}
// TODO: use a TLS cache
var iterator = new BinaryExpressionIterator();
// a b c / d + e
// stack will contain:
// [0] a
// [1] implicit *
// [2] b
// [3] implicit *
// [4] c
// [5] /
// [6] d
// [7] +
// [8] e
FlattenBinaryExpressions(context, binaryExpression, iterator);
return(ParseBinaryExpressionTree(iterator, 0, false));
}
public override ScriptNode Visit(ScriptBinaryExpression node)
{
if (_isScientific)
{
var newNode = ScientificFunctionCallRewriter.Rewrite(_context, node);
if (newNode != node)
{
return(Visit((ScriptNode)newNode));
}
}
var binaryExpression = (ScriptBinaryExpression)base.Visit((ScriptBinaryExpression)node);
// We don't surround range with spaces
if (_flags.HasFlags(ScriptFormatterFlags.AddSpaceBetweenOperators))
{
if (binaryExpression.Operator < ScriptBinaryOperator.RangeInclude)
{
binaryExpression.OperatorToken.AddLeadingSpace();
binaryExpression.OperatorToken.AddSpaceAfter();
}
}
if (_flags.HasFlags(ScriptFormatterFlags.ExplicitParenthesis))
{
if (binaryExpression.Operator == ScriptBinaryOperator.Divide || binaryExpression.Operator == ScriptBinaryOperator.DivideRound || (_isScientific && binaryExpression.Operator == ScriptBinaryOperator.Power))
{
if (binaryExpression.Left is ScriptBinaryExpression leftBin && HasSimilarPrecedenceThanMultiply(leftBin.Operator))
{
binaryExpression.Left = null;
var nested = new ScriptNestedExpression(leftBin);
binaryExpression.Left = nested;
leftBin.MoveTrailingTriviasTo(nested.CloseParen, true);
}
if (binaryExpression.Right is ScriptBinaryExpression rightBin && HasSimilarPrecedenceThanMultiply(rightBin.Operator))
{
binaryExpression.Right = null;
var nested = new ScriptNestedExpression(rightBin);
binaryExpression.Right = nested;
rightBin.MoveTrailingTriviasTo(nested.CloseParen, true);
}
}
if (binaryExpression.Operator == ScriptBinaryOperator.Divide || binaryExpression.Operator == ScriptBinaryOperator.DivideRound || (_isScientific && binaryExpression.Operator == ScriptBinaryOperator.Power))
{
var nested = new ScriptNestedExpression()
{
Expression = binaryExpression
};
binaryExpression.MoveTrailingTriviasTo(nested.CloseParen, true);
return(nested);
}
}
return(binaryExpression);
}
public override object Evaluate(TemplateContext context)
{
var caseValue = context.PeekCase();
foreach (var value in Values)
{
var whenValue = context.Evaluate(value);
var result = ScriptBinaryExpression.Evaluate(context, Span, ScriptBinaryOperator.CompareEqual, caseValue, whenValue);
if (result is bool && (bool)result)
{
return(context.Evaluate(Body));
}
}
return(context.Evaluate(Next));
}
private static ScriptExpression ParseBinaryExpressionTree(BinaryExpressionIterator it, int precedence, bool isExpectingExpression)
{
ScriptExpression leftOperand = null;
while (it.HasCurrent)
{
var op = it.Current;
var nextOperand = op.Expression;
if (nextOperand == null)
{
var newPrecedence = Parser.GetDefaultBinaryOperatorPrecedence(op.Operator);
// Probe if the next argument is a function call
if (!isExpectingExpression && it.HasNext && it.PeekNext().CallKind != FunctionCallKind.None)
{
// If it is a function call, use its precedence
newPrecedence = newPrecedence < ImplicitFunctionCallPrecedence ? newPrecedence : ImplicitFunctionCallPrecedence;
}
if (newPrecedence <= precedence)
{
break;
}
it.MoveNext(); // Skip operator
var binary = new ScriptBinaryExpression
{
Left = leftOperand,
Operator = op.Operator,
OperatorToken = op.OperatorToken ?? ScriptToken.Star(), // Force an explicit token so that we don't enter an infinite loop when formatting an expression
Span =
{
Start = leftOperand.Span.Start
},
};
binary.Right = ParseBinaryExpressionTree(it, newPrecedence, isExpectingExpression);
binary.Span.End = binary.Right.Span.End;
leftOperand = binary;
}
else
{
if (!isExpectingExpression && op.CallKind != FunctionCallKind.None)
{
var functionCall = new ScriptFunctionCall
{
Target = nextOperand,
ExplicitCall = true,
Span =
{
Start = nextOperand.Span.Start
}
};
// Skip the function and move to the operator
if (!it.MoveNext())
{
throw new ScriptRuntimeException(nextOperand.Span, $"The function is expecting at least one argument");
}
// We are expecting only an implicit multiply. Anything else is invalid.
if (it.Current.Expression == null && (it.Current.Operator != ScriptBinaryOperator.Multiply || it.Current.OperatorToken != null))
{
throw new ScriptRuntimeException(nextOperand.Span, $"The function expecting one argument cannot be followed by the operator {it.Current.OperatorToken?.ToString() ?? it.Current.Operator.ToText()}");
}
// Skip the operator
if (!it.MoveNext())
{
throw new ScriptRuntimeException(nextOperand.Span, $"The function is expecting at least one argument");
}
var argExpression = ParseBinaryExpressionTree(it, ImplicitFunctionCallPrecedence, op.CallKind == FunctionCallKind.Expression);
functionCall.Arguments.Add(argExpression);
functionCall.Span.End = argExpression.Span.End;
leftOperand = functionCall;
continue;
}
leftOperand = nextOperand;
it.MoveNext();
}
}
return(leftOperand);
}
private ScriptExpression Rewrite(TemplateContext context, int precedence, bool expectingExpression = false)
{
ScriptExpression leftValue = null;
while (_index < Count)
{
ScriptExpression nextExpression = this[_index];
// leftValue (*/^%)
if (nextExpression is ScriptArgumentBinary bin)
{
if (leftValue == null)
{
throw new ScriptRuntimeException(nextExpression.Span, precedence == 0 ? "This operator cannot be after a function call." : "This operator cannot be applied here.");
}
// Power has higher precedence than */%
var newPrecedence = Parser.GetDefaultBinaryOperatorPrecedence(bin.Operator);
if (newPrecedence <= precedence) // if new operator has lower precedence than previous, exit
{
break;
}
var rightArgExpr = this[_index + 1];
if (rightArgExpr is IScriptVariablePath)
{
var rightArg = context.Evaluate(rightArgExpr, true);
if (rightArg is IScriptCustomFunction function)
{
var maxArg = function.RequiredParameterCount;
if (maxArg >= 1 && PrecedenceTopLevel != precedence)
{
break;
}
}
}
// Skip the binary argument
_index++;
var rightValue = Rewrite(context, newPrecedence);
leftValue = new ScriptBinaryExpression()
{
Left = leftValue,
Operator = bin.Operator,
OperatorToken = bin.Operator.ToToken(),
Right = rightValue,
};
continue;
}
object result = null;
if (!expectingExpression && nextExpression is IScriptVariablePath)
{
var restoreStrictVariables = context.StrictVariables;
// Don't fail on trying to lookup for a variable
context.StrictVariables = false;
try
{
result = context.Evaluate(nextExpression, true);
}
catch (ScriptRuntimeException) when(context.IgnoreExceptionsWhileRewritingScientific)
{
// ignore any exceptions during trial evaluating as we could try to evaluate
// variable that aren't setup
}
finally
{
context.StrictVariables = restoreStrictVariables;
}
// If one argument is a function, the remaining arguments
if (result is IScriptCustomFunction function)
{
var maxArg = function.RequiredParameterCount != 0 ? function.RequiredParameterCount : function.ParameterCount > 0 ? 1 : 0;
if (maxArg > 0)
{
if (PrecedenceTopLevel == precedence || leftValue == null)
{
var functionCall = new ScriptFunctionCall {
Target = (ScriptExpression)nextExpression.Clone(), ExplicitCall = true
};
_index++;
var isExpectingExpression = function.IsParameterType <ScriptExpression>(0);
if (_index == Count)
{
throw new ScriptRuntimeException(nextExpression.Span, "The function is expecting a parameter");
}
var arg = Rewrite(context, 0, isExpectingExpression);
functionCall.Arguments.Add(arg);
if (leftValue == null)
{
leftValue = functionCall;
}
else
{
leftValue = new ScriptBinaryExpression()
{
Left = leftValue,
Operator = ScriptBinaryOperator.Multiply,
OperatorToken = ScriptToken.Star(),
Right = functionCall,
};
}
continue;
}
else
{
break;
}
}
}
}
{
if (leftValue == null)
{
leftValue = (ScriptExpression)nextExpression.Clone();
_index++;
}
else
{
int precedenceOfImplicitMultiply = result is IScriptCustomImplicitMultiplyPrecedence ? PrecedenceOfMultiply : PrecedenceOfMultiply + 1;
if (precedenceOfImplicitMultiply <= precedence)
{
break;
}
// Implicit the binary argument
var rightValue = Rewrite(context, precedenceOfImplicitMultiply);
if (rightValue is ScriptLiteral)
{
throw new ScriptRuntimeException(rightValue.Span, "Cannot use a literal on the right side of an implicit multiplication.");
}
leftValue = new ScriptBinaryExpression()
{
Left = leftValue,
Operator = ScriptBinaryOperator.Multiply,
OperatorToken = ScriptToken.Star(),
Right = rightValue,
};
}
}
}
return(leftValue);
}