public static StringSegment ParseBinaryExpression(this StringSegment literal, out JsExpression expr, bool filterExpression)
{
literal = literal.AdvancePastWhitespace();
literal = literal.ParseJsToken(out JsToken lhs, filterExpression: filterExpression);
JsExpression CreateSingleExpression(JsToken left)
{
if (left is JsExpression jsExpr)
{
return(jsExpr);
}
throw new ArgumentException($"Invalid Syntax: Expected Expression but was '{left}'");
}
if (literal.IsNullOrEmpty())
{
expr = CreateSingleExpression(lhs);
}
else
{
literal = literal.ParseJsToken(out JsToken token, filterExpression: filterExpression);
if (token is JsAssignment)
{
token = JsEquals.Operator;
}
if (!(token is JsBinaryOperator op))
{
throw new ArgumentException(
$"Invalid syntax: Expected binary operand but instead found '{token}' near: {literal.SubstringWithElipsis(0, 50)}");
}
var prec = JsTokenUtils.GetBinaryPrecedence(op.Token);
if (prec > 0)
{
literal = literal.ParseJsToken(out JsToken rhs, filterExpression: filterExpression);
var stack = new Stack <JsToken>();
stack.Push(lhs);
stack.Push(op);
stack.Push(rhs);
var precedences = new List <int> {
prec
};
while (true)
{
literal = literal.AdvancePastWhitespace();
if (filterExpression && literal.Length > 2 && (literal.GetChar(0) == '|' && literal.GetChar(1) != '|'))
{
break;
}
prec = literal.GetNextBinaryPrecedence();
if (prec == 0)
{
break;
}
while ((stack.Count > 2) && prec <= precedences[precedences.Count - 1])
{
rhs = stack.Pop();
var operand = (JsBinaryOperator)stack.Pop();
precedences.RemoveAt(precedences.Count - 1);
lhs = stack.Pop();
stack.Push(CreateJsExpression(lhs, operand, rhs));
}
literal = literal.ParseJsToken(out var opToken, filterExpression: filterExpression);
if (literal.IsNullOrEmpty())
{
throw new ArgumentException($"Invalid syntax: Expected expression after '{token}'");
}
literal = literal.ParseJsToken(out token, filterExpression: filterExpression);
stack.Push(opToken);
stack.Push(token);
precedences.Add(prec);
}
var i = stack.Count - 1;
var ret = stack.Pop();
while (stack.Count > 0)
{
op = (JsBinaryOperator)stack.Pop();
lhs = stack.Pop();
ret = CreateJsExpression(lhs, op, ret);
}
expr = (JsExpression)ret;
}
else
{
expr = CreateSingleExpression(lhs);
}
}
return(literal);
}
public static StringSegment ParseNextToken(this StringSegment literal, out object value, out JsBinding binding, bool allowWhitespaceSyntax)
{
binding = null;
value = null;
var c = (char)0;
if (literal.IsNullOrEmpty())
{
return(TypeConstants.EmptyStringSegment);
}
var i = 0;
literal = literal.AdvancePastWhitespace();
var firstChar = literal.GetChar(0);
if (firstChar == '\'' || firstChar == '"' || firstChar == '`')
{
i = 1;
var hasEscapeChar = false;
while (i < literal.Length && ((c = literal.GetChar(i)) != firstChar || literal.GetChar(i - 1) == '\\'))
{
i++;
if (!hasEscapeChar)
{
hasEscapeChar = c == '\\';
}
}
if (i >= literal.Length || literal.GetChar(i) != firstChar)
{
throw new ArgumentException($"Unterminated string literal: {literal}");
}
var str = literal.Substring(1, i - 1);
value = str;
if (hasEscapeChar)
{
var sb = StringBuilderCache.Allocate();
for (var j = 0; j < str.Length; j++)
{
// strip the back-slash used to escape quote char in strings
var ch = str[j];
if (ch != '\\' || (j + 1 >= str.Length || str[j + 1] != firstChar))
{
sb.Append(ch);
}
}
value = StringBuilderCache.ReturnAndFree(sb);
}
return(literal.Advance(i + 1));
}
if (firstChar >= '0' && firstChar <= '9' || (literal.Length >= 2 && (firstChar == '-' || firstChar == '+') && literal.GetChar(1).IsNumericChar()))
{
i = 1;
var hasExponent = false;
var hasDecimal = false;
while (i < literal.Length && IsNumericChar(c = literal.GetChar(i)) ||
(hasExponent = (c == 'e' || c == 'E')))
{
if (c == '.')
{
hasDecimal = true;
}
i++;
if (hasExponent)
{
i += 2; // [e+1]0
while (i < literal.Length && IsNumericChar(literal.GetChar(i)))
{
i++;
}
break;
}
}
var numLiteral = literal.Subsegment(0, i);
//don't convert into ternary to avoid Type coercion
if (hasDecimal || hasExponent)
{
value = numLiteral.TryParseDouble(out double d) ? d : default(double);
}
else
{
value = numLiteral.ParseSignedInteger();
}
return(literal.Advance(i));
}
if (firstChar == '{')
{
var map = new Dictionary <string, object>();
literal = literal.Advance(1);
while (!literal.IsNullOrEmpty())
{
if (literal.GetChar(0) == '}')
{
literal = literal.Advance(1);
break;
}
literal = literal.ParseNextToken(out object mapKeyString, out JsBinding mapKeyVar);
if (mapKeyVar is JsExpression)
{
throw new NotSupportedException($"JsExpression '{mapKeyVar?.Binding}' is not a valid Object key.");
}
var mapKey = mapKeyVar != null
? mapKeyVar.Binding.Value
: (string)mapKeyString;
if (mapKey != null)
{
literal = literal.AdvancePastWhitespace();
if (literal.Length > 0 && literal.GetChar(0) == ':')
{
literal = literal.Advance(1);
literal = literal.ParseNextToken(out object mapValue, out JsBinding mapValueBinding);
map[mapKey] = mapValue ?? mapValueBinding;
}
else //shorthand notation
{
if (literal.Length == 0 || (c = literal.GetChar(0)) != ',' && c != '}')
{
throw new ArgumentException($"Unterminated object literal near: {literal.SubstringWithElipsis(0, 50)}");
}
map[mapKey] = new JsBinding(mapKey);
}
}
literal = literal.AdvancePastWhitespace();
if (literal.IsNullOrEmpty())
{
break;
}
if (literal.GetChar(0) == '}')
{
literal = literal.Advance(1);
break;
}
literal = literal.AdvancePastChar(',');
literal = literal.AdvancePastWhitespace();
}
value = map;
return(literal);
}
if (firstChar == '[')
{
var list = new List <object>();
literal = literal.Advance(1);
while (!literal.IsNullOrEmpty())
{
if (literal.GetChar(0) == ']')
{
literal = literal.Advance(1);
break;
}
literal = literal.ParseNextToken(out object mapValue, out JsBinding mapVarRef);
list.Add(mapVarRef ?? mapValue);
literal = literal.AdvancePastWhitespace();
if (literal.IsNullOrEmpty())
{
break;
}
if (literal.GetChar(0) == ']')
{
literal = literal.Advance(1);
break;
}
literal = literal.AdvancePastWhitespace();
c = literal.GetChar(0);
if (c == ']')
{
literal = literal.Advance(1);
break;
}
if (c != ',')
{
throw new ArgumentException($"Unterminated array literal near: {literal.SubstringWithElipsis(0, 50)}");
}
literal = literal.Advance(1);
literal = literal.AdvancePastWhitespace();
}
literal = literal.AdvancePastWhitespace();
value = list;
return(literal);
}
if (literal.StartsWith("true") && (literal.Length == 4 || !IsValidVarNameChar(literal.GetChar(4))))
{
value = true;
return(literal.Advance(4));
}
if (literal.StartsWith("false") && (literal.Length == 5 || !IsValidVarNameChar(literal.GetChar(5))))
{
value = false;
return(literal.Advance(5));
}
if (literal.StartsWith("null") && (literal.Length == 4 || !IsValidVarNameChar(literal.GetChar(4))))
{
value = JsNull.Value;
return(literal.Advance(4));
}
if (firstChar.IsOperatorChar())
{
if (literal.StartsWith(">="))
{
binding = JsGreaterThanEqual.Operand;
return(literal.Advance(2));
}
if (literal.StartsWith("<="))
{
binding = JsLessThanEqual.Operand;
return(literal.Advance(2));
}
if (literal.StartsWith("!=="))
{
binding = JsStrictNotEquals.Operand;
return(literal.Advance(3));
}
if (literal.StartsWith("!="))
{
binding = JsNotEquals.Operand;
return(literal.Advance(2));
}
if (literal.StartsWith("==="))
{
binding = JsStrictEquals.Operand;
return(literal.Advance(3));
}
if (literal.StartsWith("=="))
{
binding = JsEquals.Operand;
return(literal.Advance(2));
}
if (literal.StartsWith("||"))
{
binding = JsOr.Operator;
return(literal.Advance(2));
}
if (literal.StartsWith("&&"))
{
binding = JsAnd.Operator;
return(literal.Advance(2));
}
switch (firstChar)
{
case '>':
binding = JsGreaterThan.Operand;
return(literal.Advance(1));
case '<':
binding = JsLessThan.Operand;
return(literal.Advance(1));
case '=':
binding = JsAssignment.Operator;
return(literal.Advance(1));
case '!':
binding = JsNot.Operator;
return(literal.Advance(1));
case '+':
binding = JsAddition.Operator;
return(literal.Advance(1));
case '-':
binding = JsSubtraction.Operator;
return(literal.Advance(1));
case '*':
binding = JsMultiplication.Operator;
return(literal.Advance(1));
case '\\':
binding = JsDivision.Operator;
return(literal.Advance(1));
case '|':
binding = JsBitwiseOr.Operator;
return(literal.Advance(1));
case '&':
binding = JsBitwiseAnd.Operator;
return(literal.Advance(1));
default:
throw new NotSupportedException($"Invalid Operator found near: '{literal.SubstringWithElipsis(0, 50)}'");
}
}
// name
i = 1;
var isExpression = false;
var hadWhitespace = false;
while (i < literal.Length && IsValidVarNameChar(c = literal.GetChar(i)) ||
(isExpression = c.IsBindingExpressionChar() || (allowWhitespaceSyntax && c == ':')))
{
if (isExpression)
{
literal = literal.ParseNextExpression(out JsExpression expr);
binding = expr;
return(literal);
}
i++;
while (i < literal.Length && literal.GetChar(i).IsWhiteSpace()) // advance past whitespace
{
i++;
hadWhitespace = true;
}
if (hadWhitespace && (i >= literal.Length || !literal.GetChar(i).IsBindingExpressionChar()))
{
break;
}
}
binding = new JsBinding(literal.Subsegment(0, i).TrimEnd());
return(literal.Advance(i));
}
public static StringSegment ParseNextToken(this StringSegment literal, out object value, out JsBinding binding)
{
binding = null;
value = null;
var c = (char)0;
if (literal.IsNullOrEmpty())
{
return(TypeConstants.EmptyStringSegment);
}
var i = 0;
literal = literal.AdvancePastWhitespace();
var firstChar = literal.GetChar(0);
if (firstChar == '\'' || firstChar == '"')
{
i = 1;
while (i < literal.Length && (literal.GetChar(i) != firstChar || literal.GetChar(i - 1) == '\\'))
{
i++;
}
if (i >= literal.Length || literal.GetChar(i) != firstChar)
{
throw new ArgumentException($"Unterminated string literal: {literal}");
}
value = literal.Substring(1, i - 1);
return(literal.Advance(i));
}
if (firstChar >= '0' && firstChar <= '9' || firstChar == '-' || firstChar == '+')
{
i = 1;
var hasExponent = false;
var hasDecimal = false;
while (i < literal.Length && IsValidNumericChar(c = literal.GetChar(i)) ||
(hasExponent = (c == 'e' || c == 'E')))
{
if (c == '.')
{
hasDecimal = true;
}
i++;
if (hasExponent)
{
i += 2; // [e+1]0
while (i < literal.Length && IsValidNumericChar(literal.GetChar(i)))
{
i++;
}
break;
}
}
var numLiteral = literal.Subsegment(0, i);
//don't convert into ternary to avoid Type coercion
if (hasDecimal || hasExponent)
{
value = numLiteral.TryParseDouble(out double d) ? d : default(double);
}
else
{
value = numLiteral.ParseSignedInteger();
}
return(literal.Advance(i));
}
if (firstChar == '{')
{
var map = new Dictionary <string, object>();
literal = literal.Advance(1);
while (!literal.IsNullOrEmpty())
{
literal = literal.ParseNextToken(out object mapKeyString, out JsBinding mapKeyVar);
if (mapKeyVar is JsExpression)
{
throw new NotSupportedException($"JsExpression '{mapKeyVar?.Binding}' is not a valid Object key.");
}
var mapKey = mapKeyVar != null
? mapKeyVar.Binding.Value
: (string)mapKeyString;
if (mapKey != null)
{
literal = literal.AdvancePastChar(':');
literal = literal.ParseNextToken(out object mapValue, out JsBinding mapValueBinding);
map[mapKey] = mapValue ?? mapValueBinding;
}
literal = literal.AdvancePastWhitespace();
if (literal.IsNullOrEmpty())
{
break;
}
if (literal.GetChar(0) == '}')
{
literal = literal.Advance(1);
break;
}
literal = literal.AdvancePastChar(',');
literal = literal.AdvancePastWhitespace();
}
value = map;
return(literal);
}
if (firstChar == '[')
{
var list = new List <object>();
literal = literal.Advance(1);
while (!literal.IsNullOrEmpty() && literal.GetChar(0) != ']')
{
literal = literal.ParseNextToken(out object mapValue, out JsBinding mapVarRef);
list.Add(mapVarRef ?? mapValue);
literal = literal.AdvancePastWhitespace();
if (literal.IsNullOrEmpty())
{
break;
}
if (literal.GetChar(0) == ']')
{
literal = literal.Advance(1);
break;
}
literal = literal.AdvancePastChar(',');
literal = literal.AdvancePastWhitespace();
}
value = list;
return(literal);
}
if (literal.StartsWith("true") && (literal.Length == 4 || !IsValidVarNameChar(literal.GetChar(4))))
{
value = true;
return(literal.Advance(4));
}
if (literal.StartsWith("false") && (literal.Length == 5 || !IsValidVarNameChar(literal.GetChar(5))))
{
value = false;
return(literal.Advance(5));
}
if (literal.StartsWith("null") && (literal.Length == 4 || !IsValidVarNameChar(literal.GetChar(4))))
{
value = JsNull.Value;
return(literal.Advance(4));
}
// name
i = 1;
var isExpression = false;
while (i < literal.Length && IsValidVarNameChar(c = literal.GetChar(i)) ||
(isExpression = (c == '.' || c == '(' || c == '[')))
{
if (isExpression)
{
binding = literal.ParseJsExpression(out int pos).FirstOrDefault();
return(literal.Advance(pos));
}
i++;
while (i < literal.Length && literal.GetChar(i).IsWhiteSpace()) // advance past whitespace
{
i++;
}
}
binding = new JsBinding(literal.Subsegment(0, i).TrimEnd());
return(literal.Advance(i));
}
internal static StringSegment ParseArguments(this StringSegment literal, out List <JsToken> arguments, char termination)
{
arguments = new List <JsToken>();
while (!literal.IsNullOrEmpty())
{
JsToken listValue;
literal = literal.AdvancePastWhitespace();
if (literal.GetChar(0) == termination)
{
literal = literal.Advance(1);
break;
}
if (literal.StartsWith("..."))
{
literal = literal.Advance(3);
literal = literal.ParseJsExpression(out listValue);
if (!(listValue is JsIdentifier) && !(listValue is JsArrayExpression))
{
throw new SyntaxErrorException($"Spread operator expected array but instead found {listValue.DebugToken()}");
}
listValue = new JsSpreadElement(listValue);
}
else
{
literal = literal.ParseJsExpression(out listValue);
}
arguments.Add(listValue);
literal = literal.AdvancePastWhitespace();
if (literal.IsNullOrEmpty())
{
break;
}
if (literal.GetChar(0) == termination)
{
literal = literal.Advance(1);
break;
}
literal = literal.AdvancePastWhitespace();
var c = literal.SafeGetChar(0);
if (c.IsEnd() || c == termination)
{
literal = literal.Advance(1);
break;
}
if (c != ',')
{
throw new SyntaxErrorException($"Unterminated arguments expression near: {literal.DebugLiteral()}");
}
literal = literal.Advance(1);
literal = literal.AdvancePastWhitespace();
}
literal = literal.AdvancePastWhitespace();
return(literal);
}
public static StringSegment ParseBinaryExpression(this StringSegment literal, out JsExpression expr, bool filterExpression)
{
literal = literal.AdvancePastWhitespace();
literal = literal.ParseJsToken(out var lhs, filterExpression: filterExpression);
if (literal.IsNullOrEmpty())
{
expr = lhs is JsExpression jsExpr
? jsExpr
: throw new SyntaxErrorException($"Expected Expression but was {lhs.DebugToken()}");
}
else
{
literal = literal.ParseJsBinaryOperator(out var op);
if (op == null)
{
throw new SyntaxErrorException($"Expected binary operator near: {literal.DebugLiteral()}");
}
var prec = JsTokenUtils.GetBinaryPrecedence(op.Token);
if (prec > 0)
{
literal = literal.ParseJsToken(out JsToken rhs, filterExpression: filterExpression);
var stack = new Stack <JsToken>();
stack.Push(lhs);
stack.Push(op);
stack.Push(rhs);
var precedences = new List <int> {
prec
};
while (true)
{
literal = literal.AdvancePastWhitespace();
if (filterExpression && literal.Length > 2 && (literal.GetChar(0) == '|' && literal.GetChar(1) != '|'))
{
break;
}
prec = literal.GetNextBinaryPrecedence();
if (prec == 0)
{
break;
}
while ((stack.Count > 2) && prec <= precedences[precedences.Count - 1])
{
rhs = stack.Pop();
var operand = (JsBinaryOperator)stack.Pop();
precedences.RemoveAt(precedences.Count - 1);
lhs = stack.Pop();
stack.Push(CreateJsExpression(lhs, operand, rhs));
}
literal = literal.ParseJsBinaryOperator(out op);
if (literal.IsNullOrEmpty())
{
throw new SyntaxErrorException($"Expected expression near: '{literal.DebugLiteral()}'");
}
literal = literal.ParseJsToken(out var token, filterExpression: filterExpression);
stack.Push(op);
stack.Push(token);
precedences.Add(prec);
}
var i = stack.Count - 1;
var ret = stack.Pop();
while (stack.Count > 0)
{
op = (JsBinaryOperator)stack.Pop();
lhs = stack.Pop();
ret = CreateJsExpression(lhs, op, ret);
}
expr = (JsExpression)ret;
}
else
{
expr = lhs is JsExpression jsExpr
? jsExpr
: throw new SyntaxErrorException($"Expected Expression but was {lhs.DebugToken()}");
}
}
return(literal);
}