private LanguageExpression ConvertString(StringSyntax syntax)
{
if (syntax.TryGetLiteralValue() is string literalStringValue)
{
// no need to build a format string
return(new JTokenExpression(literalStringValue));;
}
if (syntax.Expressions.Length == 1)
{
const string emptyStringOpen = LanguageConstants.StringDelimiter + LanguageConstants.StringHoleOpen; // '${
const string emptyStringClose = LanguageConstants.StringHoleClose + LanguageConstants.StringDelimiter; // }'
// Special-case interpolation of format '${myValue}' because it's a common pattern for userAssignedIdentities.
// There's no need for a 'format' function because we just have a single expression with no outer formatting.
if (syntax.StringTokens[0].Text == emptyStringOpen && syntax.StringTokens[1].Text == emptyStringClose)
{
return(ConvertExpression(syntax.Expressions[0]));
}
}
var formatArgs = new LanguageExpression[syntax.Expressions.Length + 1];
var formatString = StringFormatConverter.BuildFormatString(syntax);
formatArgs[0] = new JTokenExpression(formatString);
for (var i = 0; i < syntax.Expressions.Length; i++)
{
formatArgs[i + 1] = ConvertExpression(syntax.Expressions[i]);
}
return(CreateFunction("format", formatArgs));
}
public override void VisitStringSyntax(StringSyntax syntax)
=> AssignType(syntax, () => {
if (syntax.TryGetLiteralValue() is string literalValue)
{
// uninterpolated strings have a known type
return(new StringLiteralType(literalValue));
}
var errors = new List <ErrorDiagnostic>();
foreach (var interpolatedExpression in syntax.Expressions)
{
var expressionType = typeManager.GetTypeInfo(interpolatedExpression);
CollectErrors(errors, expressionType);
}
if (errors.Any())
{
return(new ErrorTypeSymbol(errors));
}
// normally we would also do an assignability check, but we allow "any" type in string interpolation expressions
// so the assignability check cannot possibly fail (we already collected type errors from the inner expressions at this point)
return(LanguageConstants.String);
});