What is meaning of TVC in "TVC:UKX", "TVC:DAX" symbol on TradingView? On other Pairs it denotes the broker providing that quotes. But in this case I don't find any broker or Exchange named after "TVC". So what is this TVC on tradingview?
I have also tried to understand where this data is coming from, I guess an email to support would answer the question.
A guess would be TradingViewCQG (meaning data from the vendor CQG)...
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I am working with antlr4 to parse some inner language.
The way I do it is the standard way of creating a stream of tokens, then creating a parse tree with set tokens. And the last step is creating a tree.
Now that I have a tree I can use the walk command to walk over it.
The walk command and the parse tree being created are an extension of the BaseListener class.
For my project I use many lookaheads, I mostly use the visitors as a sort of look ahead.
A visitor function can be applied on a node from the parser tree. (Assuming you implement a visitor class)
I have tried creating a smaller listener class to act as my look ahead on a specific node. However, I'm not managing to figure out if this is even possible.
Or is there another / better / smarter way to create a look ahead?
To make the question seem shorter:
Can a listener class be used on a node in the antlr4 parser tree-like visitor can?
There’s no real reason to do anything fancy with a listener here. To handle your example of resolving the type of an expression, this can be done in a couple of steps. You’ll need a listener that builds a symbol table (presumably a scoped symbol table so that each scope in your parse tree has a symbol table and references to “parent” scopes it might search to resolve the data types of any variables.). Depending upon your needs, you can build these scoped symbol tables in your listener, pushing and popping them on a stack as you enter/exit scopes, or you may do this is a separate listener attaching a reference to scope nodes to your parse tree. This symbol table will be required for type resolution, so if you can reference variables in your source prior to encountering the declaration, you’d need too pass your tree with a listener building and retaining the symbol table structure.
With the symbol table structure available to your listener for resolving expression types. If you always use the exit* method overrides then all of the data types for any sub-expressions will have already been resolved. With all of the sub-expression types, you can infer the type of the expression you’re about to “exit”. Evaluating the type of child expressions should cover all of the “lookahead” you need to resolve an expression’s type.
There’s really nothing about this approach that rules out a visitor either, it would just be up to you to visit each child, determining it’s type, and then, at the end of the listener, resolve the expression type from the types of it’s children.
I've found several references to SAD/AD/XAD data types in the HL7 spec, but don't see anything about this info being used to describe facilities, such as those described in the AIL segment (e.g. "2^BLUE HILL FACILITY"). But where, if anywhere, can I expect to get data about that facility, such as name, street address, etc.?
In the PV1 segment definition for HL7 2.x there isn't a dedicated field for Facility Address specifically. If you are the receiving system in this case, you may have to request that data be sent or added in from the sending system. This could be as simple as placing it in the PV1-5.X field (X being whatever subfield the sending system decides on), or adding in a custom Z segment (ZPV for example) to have this data transmitted.
Since there is no standard field for this kind of data in the PV1 segment though, you will have to confirm that the sending system can in fact send this data.
The facility name will be in a separate field. It varies from segment to segment. You just have to read the segment definition and pick the right field.
I get a weird text symbol when I output the content of a NSString. A user sent its database and it is stored in core data. This is what the symbol looks like:
I guess it does have some specific code, or is it a not supported character? The user can't explain from where such symbol comes from.
Thanks
Look at NSString's class description. You can use the 'canBeConvertedToEncoding' iteratively, with all possible encodings listed in the 'String Encodings' section at the bottom, to find out which one your strings use.
I have a stored procedure for SQL 2000 that has an input parameter with a data type of varchar(17) to handle a vehicle identifier (VIN) that is alphanumeric. However, whenever I enter a value for the parameter when executing that has a numerical digit in it, it gives me an error. It appears to only accept alphabetic characters. What am I doing wrong here?
Based on comments, there is a subtle "feature" of SQL Server that allows letters a-z to be used as stored proc parameters without delimiters. It's been there forever (since 6.5 at least)
I'm not sure of the full rules, but it's demonstrated in MSDN (rename SQL Server etc): there are no delimiters around the "local" parameter. And I just found this KB article on it
In this case, it could be starting with a number that breaks. I assume it works for a contained number (but as I said I'm not sure of the full rules).
Edit: confirmed by Martin as "breaks with leading number", OK for "containing number"
This doesn't help much, but somewhere, you have a bug, typo, or oversight in your code. I spent 2+ years working with VINs as parameters, and other than regretting not having made it char(17) instead ov varchar(17), we never had any problems passing in alphanumeric VIN values. Somewhere, and I'd guess it's in the application layer, something is not liking digits -- perhaps a filter looking for only alphabetical characters?
I came across the following URL today:
http://www.sfgate.com/cgi-bin/blogs/inmarin/detail??blogid=122&entry_id=64497
Notice the doubled question mark at the beginning of the query string:
??blogid=122&entry_id=64497
My browser didn't seem to have any trouble with it, and running a quick bookmarklet:
javascript:alert(document.location.search);
just gave me the query string shown above.
Is this a valid URL? The reason I'm being so pedantic (assuming that I am) is because I need to parse URLs like this for query parameters, and supporting doubled question marks would require some changes to my code. Obviously if they're in the wild, I'll need to support them; I'm mainly curious if it's my fault for not adhering to URL standards exactly, or if it's in fact a non-standard URL.
Yes, it is valid. Only the first ? in a URL has significance, any after it are treated as literal question marks:
The query component is indicated by
the first question mark ("?")
character and terminated by a number
sign ("#") character or by the end of
the URI.
...
The characters slash ("/") and
question mark ("?") may represent data
within the query component. Beware
that some older, erroneous
implementations may not handle such
data correctly when it is used as the
base URI for relative references
(Section 5.1), apparently because they
fail to distinguish query data from
path data when looking for
hierarchical separators. However, as
query components are often used to
carry identifying information in the
form of "key=value" pairs and one
frequently used value is a reference
to another URI, it is sometimes better
for usability to avoid
percent-encoding those characters.
https://www.rfc-editor.org/rfc/rfc3986#section-3.4
As a tangentially related answer, foo?spam=1?&eggs=3 gives the parameter spam the value 1?