//todo this is not the best choice of design, IdentityExpression.Parse does the same, this is just more intuitive. both can co-exist.
/// <summary>
/// In cases like: property(1,2)[0] we have chained interaction, this resolves if current <see cref="result"/> has more interactions. If so, parses them.
/// </summary>
/// <param name="result">The result expression</param>
/// <param name="ew">The walker with position right after <see cref="result"/></param>
/// <param name="caller">Internal use.</param>
/// <returns></returns>
public static Expression TryExpand(Expression result, ExpressionWalker ew, Type caller = null)
{
if (ew.Current.Token == ExpressionToken.Period)
{
return(IdentityExpression.Parse(ew, caller, result));
}
if (ew.Current.Token == ExpressionToken.LeftBracet)
{
return(IndexerCallExpression.Parse(ew, result));
}
if (ew.Current.Token == ExpressionToken.LeftParen)
{
return(CallExpression.Parse(ew, result));
}
return(result);
}
public static NewExpression Parse(ExpressionWalker ew)
{
ew.IsCurrentOrThrow(ExpressionToken.New);
ew.NextOrThrow();
return(new NewExpression(CallExpression.Parse(ew)));
}
public static IdentityExpression Parse(ExpressionWalker ew, Type caller = null, Expression left = null)
{
var ret = new IdentityExpression();
//types:
//justname
//justname.accessor
//justname.accessor[5].second
//justname.method().someval
//justname.method().someval[3].thatsfar
if (left == null)
{
ew.IsCurrentOrThrow(ExpressionToken.Literal);
}
if (ew.HasNext && ew.PeakNext.WhitespacesAfterMatch == 0 && ew.PeakNext.Token == ExpressionToken.Period && caller != typeof(IdentityExpression) || left != null)
{
var first = left ?? ParseExpression(ew, typeof(IdentityExpression));
ew.NextOrThrow(); //skip the predicted period.
var next = ew.PeakNext;
switch (next.Token)
{
//currently we are at Literal
case ExpressionToken.Period:
ret.Identity = new PropertyIdentity(first, Parse(ew));
return(ret);
case ExpressionToken.LeftBracet:
ret.Identity = new PropertyIdentity(first, IndexerCallExpression.Parse(ew));
return(ret);
case ExpressionToken.LeftParen:
ret.Identity = new PropertyIdentity(first, CallExpression.Parse(ew));
return(ret);
default:
if (left != null)
{
return(new IdentityExpression(new PropertyIdentity(left, Parse(ew, typeof(IdentityExpression), null))));
}
if (first != null)
{
//just a plain single word!
var right = new IdentityExpression();
if (ew.IsCurrent(ExpressionToken.Null))
{
right.Identity = NullIdentity.Instance;
}
else
{
ew.IsCurrentOrThrow(ExpressionToken.Literal);
right.Identity = StringIdentity.Create(ew.Current.Match);
}
ew.Next();
return(new IdentityExpression(new PropertyIdentity(first, right)));
}
goto _plain_identity;
}
}
_plain_identity:
//just a plain single word!
if (ew.IsCurrent(ExpressionToken.Null))
{
ret.Identity = NullIdentity.Instance;
}
else
{
ew.IsCurrentOrThrow(ExpressionToken.Literal);
ret.Identity = StringIdentity.Create(ew.Current.Match);
}
ew.Next();
return(ret);
}
public static Expression ParseExpression(ExpressionWalker ew, Type caller = null)
{
Expression ret = null;
_retry:
bool isOperatorCall = caller == typeof(OperatorExpression) || caller == typeof(RightOperatorExpression) || caller == typeof(ForeachExpression);
var current = ew.Current.Token;
if (current == ExpressionToken.Literal)
{
//cases like variable(.., variable[.., variable + .., variable
if (ew.HasNext)
{
var peak = ew.PeakNextOrThrow().Token;
if (peak == ExpressionToken.LeftParen)
{
ret = CallExpression.Parse(ew);
}
else if (peak == ExpressionToken.Period && caller != typeof(IdentityExpression) && caller != typeof(InteractableExpression))
{
ret = IdentityExpression.Parse(ew);
}
else if (peak == ExpressionToken.LeftBracet)
{
ret = IndexerCallExpression.Parse(ew);
}
else if (peak == ExpressionToken.New)
{
ret = NewExpression.Parse(ew);
}
else if (RightOperatorExpression.IsNextAnRightUniOperation(ew, caller) && caller != typeof(RightOperatorExpression))
{
ret = RightOperatorExpression.Parse(ew);
}
else if (OperatorExpression.IsNextAnOperation(ew) && !isOperatorCall)
{
ret = OperatorExpression.Parse(ew);
}
else
{
ret = IdentityExpression.Parse(ew, caller);
}
}
else
{
ret = IdentityExpression.Parse(ew, caller);
}
}
else if (LeftOperatorExpression.IsCurrentAnLeftUniOperation(ew))
{
ret = LeftOperatorExpression.Parse(ew);
}
else if (current == ExpressionToken.NumberLiteral)
{
ret = NumberLiteral.Parse(ew);
}
else if (current == ExpressionToken.StringLiteral)
{
ret = StringLiteral.Parse(ew);
}
else if (current == ExpressionToken.LeftParen)
{
ret = GroupExpression.Parse(ew, ExpressionToken.LeftParen, ExpressionToken.RightParen);
}
else if (current == ExpressionToken.LeftBracet)
{
ret = ArrayExpression.Parse(ew);
}
else if (current == ExpressionToken.New)
{
ret = NewExpression.Parse(ew);
}
else if (current == ExpressionToken.Boolean)
{
ret = BooleanLiteral.Parse(ew);
}
else if (current == ExpressionToken.CharLiteral)
{
ret = CharLiteral.Parse(ew);
}
else if (current == ExpressionToken.Throw)
{
ret = ThrowExpression.Parse(ew);
}
else if (current == ExpressionToken.Hashtag && ew.HasNext && ew.PeakNext.Token == ExpressionToken.NumberLiteral)
{
ret = HashtagReferenceExpression.Parse(ew, caller);
}
else if (current == ExpressionToken.Null)
{
ret = NullIdentity.Parse(ew);
}
else if (current == ExpressionToken.NewLine)
{
ew.NextOrThrow();
goto _retry;
}
else
{
throw new UnexpectedTokenException($"Token was not expected to be a {ew.Current.Token}");
}
//here we parse chained math operations
while (OperatorExpression.IsCurrentAnOperation(ew) && !isOperatorCall)
{
if (RightOperatorExpression.IsCurrentAnRightUniOperation(ew) && caller != typeof(OperatorExpression))
{
ret = RightOperatorExpression.Parse(ew, ret);
}
else if (OperatorExpression.IsCurrentAnOperation(ew))
{
ret = OperatorExpression.Parse(ew, ret);
}
}
return(ret);
}