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Type comparison operators #420

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Type comparison operators #420

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18 changes: 15 additions & 3 deletions Source/System.Management/Pash/Implementation/ExecutionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -174,7 +174,10 @@ object EvaluateBinaryExpression(BinaryExpressionAst binaryExpressionAst)
var right = LanguagePrimitives.ConvertTo<object[]>(rightOperand);
return string.Format(left, right);
}

case TokenKind.Is:
return IsInstanceOfType(leftOperand, rightOperand);
case TokenKind.IsNot:
return !IsInstanceOfType(leftOperand, rightOperand);
case TokenKind.Equals:
case TokenKind.PlusEquals:
case TokenKind.MinusEquals:
Expand All @@ -200,8 +203,6 @@ object EvaluateBinaryExpression(BinaryExpressionAst binaryExpressionAst)
case TokenKind.Cin:
case TokenKind.Cnotin:
case TokenKind.Csplit:
case TokenKind.Is:
case TokenKind.IsNot:
case TokenKind.As:
case TokenKind.Shl:
case TokenKind.Shr:
Expand All @@ -212,6 +213,17 @@ object EvaluateBinaryExpression(BinaryExpressionAst binaryExpressionAst)
}
}

private static bool IsInstanceOfType(object leftOperand, object rightOperand)
{
var type = rightOperand as Type;
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@ygra ygra Jul 5, 2016 •
edited
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The right operand is coerced to a type, actually.

PS Home:\> '' -is 'string'
True

I think LanguagePrimitives.ConvertTo should take care of that.

And the right operand can be an expression:

'' -is [type]'string'
3 -is 'int'+32

Not sure right now whether that's already covered here.

Granted, we don't have to fix those in the first iteration, but we should keep it in mind.

if (type == null)
{
throw new InvalidOperationException(@"The right operand of '-is' must be a type.");
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@ygra ygra Jul 5, 2016 •
edited
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Why a verbatim string literal here?

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To emphasise localisable text only literal.

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@ygra, I think that some tools such as Resharper will throw a warning here mentioning "possibly localizable string". Making a literal verbatim is really a way to suppress this warning. So:

a) I don't think we generally use this practice in Pash code
b) that's really a localizable string, so it would be improper to just suppress the warning. If we one day will ultimately decide to localize Pash (what's unlikely but possible), we'll need to localize it.

So I don't think that you should use verbatim string literal here. Better get rid of that.

}

return type.IsInstanceOfType(leftOperand);
}

private bool Match(object leftOperand, object rightOperand, RegexOptions regexOptions)
{
if (!(leftOperand is string) || !(rightOperand is string))
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