I am trying to come up with what backtick really means. hopen backtick means localhost key backtick returns contexts in a q session. I am guessing it is internally referencing a dictionary. Backtick in a queue SQL means modifying that table.
You could think of it as the default symbol so its meaning depends on a function - hopen, key, vs/sv and etc - that accepts a sym param.
WBR, Andrey.
???, 2 ??? 2015 ?., 19:40:42 UTC+3 ??? analyst ???:
I am trying to come up with what backtick really means.
hopen backtick means localhost
key backtick returns contexts in a q session. I am guessing it is internally referencing a dictionary.
Backtick in a queue SQL means modifying that table.
the backtick ` is the null value for the datatype symbol.
what functions like hopen, key, … do with it depends on the function.
backtick marks literal symbols it’s a type signifier, like thetrailing letters used for the other types (0b “0 as a boolean”, 7h "7as a short (integer), 1f “one as a (64-bit) float”, etc.)it’s like leading unpaired apostrophe from lisp, if that helps at allbacktick on its own is the null symbol and has various meanings tovarious functionsnote that keyis missing, the relative name of the default context. the implied relationship is that all contexts are siblings at thesame (first) level in a tree whose root is named (the empty stringas a sym), and the default context is also (relatively) named ;absolute names are formed by adding a dot between the parent andchild, so the default context is named . (empty string, dot, emptystring); key. is a list of the contents of the default namespace,key.q of the .q namespace, etc.in some cases, a symbol is interpreted as the name of a globalvariable, and some functions will behave differently when given avariable to operate on by its name (f`x) rather than its value (f x);this can be thought of as somewhat like pass-by-name vs.pass-by-value, though keep in mind it’s not completely analogousspecifically, qsql update and delete (as well as various functionslike @, ., ! in the sense of modifying table keying, xkey, etc.)modify the given table (or other thing) and save it back to memorywhen given it by name (with a backtick), but return the modified tablewhen given it by value (without a backtick)On Wed, Dec 2, 2015 at 11:33 AM, analyst <analyst.tech.jobs> wrote:> I am trying to come up with what backtick really means.>> hopen backtick means localhost>> key backtick returns contexts in a q session. I am guessing it is internally referencing a dictionary.>> Backtick in a queue SQL means modifying that table.>> –>
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