Hi guys i have issue exiting repeated field, i tried ctrl-c ctrl-d and i am still cannot exit this.
The structure is:
Events
variant_set (field contain array of variant)
variant (field contain array of value)
value
in evans CLI this looks like this:
<repeated> event::variant_set::value (TYPE_STRING) => ctrl-c
<repeated> event::variant_set::value (TYPE_STRING) => ctrl-d
<repeated> event::variant_set::value (TYPE_STRING) =>
anyone knows how to exit this input ?
It can be avoided by specify --dig-manually option.
$ evans --proto api.proto repl
> call --dig-manually Unary
https://github.com/ktr0731/evans/issues/574
Related
Well, this must be the most stupid and idiotic behavior I've seen from a programming language.
https://www.bfgroup.xyz/b2/manual/release/index.html says:
Syntactically, a Boost.Jam program consists of two kinds of
elements—keywords (which have a special meaning to Boost.Jam) and
literals. Consider this code:
a = b ;
which assigns the value b to the variable a. Here, = and ; are
keywords, while a and b are literals.
⚠ All syntax elements, even
keywords, must be separated by spaces. For example, omitting the space
character before ; will lead to a syntax error.
If you want to use a literal value that is the same as some keyword,
the value can be quoted:
a = "=" ;
OK, so far so good. So I have this in my Jamroot:
import path : basename ;
actions make_mytest_install
{
echo "make_mytest_install: MY_ROOT_PATH $(MY_ROOT_PATH) PWD $(PWD:E=not_set)" ;
epath = "$(MY_ROOT_PATH)/projects/mytest/bin/gcc-9/release/qt5client" ;
ename = basename ( $(epath) ) ;
echo "epath $(epath) ename $(ename)" ;
}
explicit install-gettext ;
make install-mytest : : #make_mytest_install ;
... and I try this:
bjam install-mytest
...updating 1 target...
Jamfile</home/USER/src/myproject>.make_mytest_install bin/install-mytest
make_mytest_install: MY_ROOT_PATH /home/USER/src/myproject PWD not_set
[ SHELL pstree -s -p 2720269 && echo PID 2720269 PWD /home/USER/src/myproject ]
/bin/sh: 13: epath: not found
/bin/sh: 14: Syntax error: "(" unexpected
.....
...failed Jamfile</home/USER/src/myproject>.make_mytest_install bin/install-mytest...
...failed updating 1 target...
Now - how come that the SIMPLEST assignment to a string, EXACTLY AS in the manual:
epath = "$(MY_ROOT_PATH)/projects/mytest/bin/gcc-9/release/qt5client" ;
... fails, and this variable cannot be found anymore?
What is the logic in this? How the hell is this supposed to work? I would get it if MY_ROOT_PATH was undefined - but the echo before it, shows that it is not? What is this lunacy?
So I cannot believe I'm asking something this trivial, but:
How do you assign a string to a variable in bjam language?
Well, the error gives somewhat of a hint: /bin/sh: -> so apparently inside actions, it is sh that runs - then again, if it was really sh I could have assigned variables, but I can't. So best I could do, was to remove the assignments OUT of actions:
import path : basename ;
epath = "$(MY_ROOT_PATH)/projects/mytest/bin/gcc-9/release/qt5client" ;
# ename = basename ( $(epath) ) ; # nope, causes target install-mytest to not be found :(
# calling a shell for basename works - but adds a damn NEWLINE at end!?!?!?!
ename = [ SHELL "basename $(epath)" ] ;
actions make_mytest_install
{
echo "make_mytest_install: MY_ROOT_PATH $(MY_ROOT_PATH) PWD $(PWD:E=not_set)" ;
echo "epath $(epath) ename $(ename)" ;
}
explicit install-mytest ;
make install-mytest : : #make_mytest_install ;
So, assignment kind of passes, but you still can't get the basename ?!
I still don't understand, who thought this kind of variable management is a good idea ... I don't even understand, how people managed to build stuff with this system
This section of my program is supposed to list all files within the directory containing ".txt" in the name but it's not returning anything when run. If I delete ".txt" and leave it as an empty string "" then it works perfectly and returns all file names including the .txt files so I can't figure out what I'm doing wrong here.
procedure Search_Directory is
use Ada.Directories;
procedure Write_Search_Item(Search_Item : in Directory_Entry_Type) is
begin
Put(Item => Simple_Name(Directory_Entry => Search_Item));
New_Line;
end Write_Search_Item;
Filter : Constant Filter_Type := (Ordinary_File => True,
Special_File => False,
Directory => True);
begin
Search(Directory => Current_Directory,
Pattern => (".txt"),
Filter => Filter,
Process => Write_Search_Item'Access);
end Search_Directory;
The Search function, defined in the package Ada.Directories, takes a pattern argument which is either a null string or a form that is implementation-defined RM A.16 (111/ 2). In GNAT, this pattern is supposed to be a regular expression (see also here) described in System.Regexp (see also here, second grammar, a "globbing pattern").
I am trying to create a dictionary of functions with symbols as keys but I am getting an error. I have tried the following:
functions = Dict{
:gauss => (v::Float64)->gauss(v, 0.0, 1.0),
:sin => (v::Float64)-> sin(v),
:nsin => (v::Float64)->(-sin(v)),
:cos => (v::Float64)-> cos(v),
:ncos => (v::Float64)->(-cos(v)),
:tanh => (v::Float64)->tanh(v),
:sigm => (v::Float64)->sigmoid(v),
:id => (v::Float64)->id(v)
}
The error I am getting :
ERROR: LoadError: TypeError: in Type, in parameter, expected Type, got Pair{Symbol,getfield(Main, Symbol("##105#113"))}
Please let me know what I am doing wrong. Thanks for the help in advance.
I figured the{} need to replaced by ().
As you found out your yourself, the {} brackets indicate type parameters whereas the paranthesis indicate a constructor call.
Note, that the ::Float64 type annotations aren't necessary for your functions to be performant. Think of them more as a user interface restriction; that is users won't be able to call your methods with non-Float64s. However, if you want to specify types explicitly, you could also specify the type of your dictionary explicitly as such Dict{Symbol, Function}(...). However, since you don't initialize the Dict empty, Julia will figure out the best type based on your input (symbol function pairs).
I am trying to learn Erlang and I am working on the practice problems Erlang has on the site. One of them is:
Write the function time:swedish_date() which returns a string containing the date in swedish YYMMDD format:
time:swedish_date()
"080901"
My function:
-module(demo).
-export([swedish_date/0]).
swedish_date() ->
[YYYY,MM,DD] = tuple_to_list(date()),
string:substr((integer_to_list(YYYY, 3,4)++pad_string(integer_to_list(MM))++pad_string(integer_to_list(DD)).
pad_string(String) ->
if
length(String) == 1 -> '0' ++ String;
true -> String
end.
I'm getting the following errors when compiled.
demo.erl:6: syntax error before: '.'
demo.erl:2: function swedish_date/0 undefined
demo.erl:9: Warning: function pad_string/1 is unused
error
How do I fix this?
After fixing your compilation errors, you're still facing runtime errors. Since you're trying to learn Erlang, it's instructive to look at your approach and see if it can be improved, and fix those runtime errors along the way.
First let's look at swedish_date/0:
swedish_date() ->
[YYYY,MM,DD] = tuple_to_list(date()),
Why convert the list to a tuple? Since you use the list elements individually and never use the list as a whole, the conversion serves no purpose. You can instead just pattern-match the returned tuple:
{YYYY,MM,DD} = date(),
Next, you're calling string:substr/1, which doesn't exist:
string:substr((integer_to_list(YYYY,3,4) ++
pad_string(integer_to_list(MM)) ++
pad_string(integer_to_list(DD))).
The string:substr/2,3 functions both take a starting position, and the 3-arity version also takes a length. You don't need either, and can avoid string:substr entirely and instead just return the assembled string:
integer_to_list(YYYY,3,4) ++
pad_string(integer_to_list(MM)) ++
pad_string(integer_to_list(DD)).
Whoops, this is still not right: there is no such function integer_to_list/3, so just replace that first call with integer_to_list/1:
integer_to_list(YYYY) ++
pad_string(integer_to_list(MM)) ++
pad_string(integer_to_list(DD)).
Next, let's look at pad_string/1:
pad_string(String) ->
if
length(String) == 1 -> '0' ++ String;
true -> String
end.
There's a runtime error here because '0' is an atom and you're attempting to append String, which is a list, to it. The error looks like this:
** exception error: bad argument
in operator ++/2
called as '0' ++ "8"
Instead of just fixing that directly, let's consider what pad_string/1 does: it adds a leading 0 character if the string is a single digit. Instead of using if to check for this condition — if isn't used that often in Erlang code — use pattern matching:
pad_string([D]) ->
[$0,D];
pad_string(S) ->
S.
The first clause matches a single-element list, and returns a new list with the element D preceded with $0, which is the character constant for the character 0. The second clause matches all other arguments and just returns whatever is passed in.
Here's the full version with all changes:
-module(demo).
-export([swedish_date/0]).
swedish_date() ->
{YYYY,MM,DD} = date(),
integer_to_list(YYYY) ++
pad_string(integer_to_list(MM)) ++
pad_string(integer_to_list(DD)).
pad_string([D]) ->
[$0,D];
pad_string(S) ->
S.
But a simpler approach would be to use the io_lib:format/2 function to just format the desired string directly:
swedish_date() ->
io_lib:format("~w~2..0w~2..0w", tuple_to_list(date())).
First, note that we're back to calling tuple_to_list(date()). This is because the second argument for io_lib:format/2 must be a list. Its first argument is a format string, which in our case says to expect three arguments, formatting each as an Erlang term, and formatting the 2nd and 3rd arguments with a width of 2 and 0-padded.
But there's still one more step to address, because if we run the io_lib:format/2 version we get:
1> demo:swedish_date().
["2015",["0",56],"29"]
Whoa, what's that? It's simply a deep list, where each element of the list is itself a list. To get the format we want, we can flatten that list:
swedish_date() ->
lists:flatten(io_lib:format("~w~2..0w~2..0w", tuple_to_list(date()))).
Executing this version gives us what we want:
2> demo:swedish_date().
"20150829"
Find the final full version of the code below.
-module(demo).
-export([swedish_date/0]).
swedish_date() ->
lists:flatten(io_lib:format("~w~2..0w~2..0w", tuple_to_list(date()))).
UPDATE: #Pascal comments that the year should be printed as 2 digits rather than 4. We can achieve this by passing the date list through a list comprehension:
swedish_date() ->
DateVals = [D rem 100 || D <- tuple_to_list(date())],
lists:flatten(io_lib:format("~w~2..0w~2..0w", DateVals)).
This applies the rem remainder operator to each of the list elements returned by tuple_to_list(date()). The operation is needless for month and day but I think it's cleaner than extracting the year and processing it individually. The result:
3> demo:swedish_date().
"150829"
There are a few issues here:
You are missing a parenthesis at the end of line 6.
You are trying to call integer_to_list/3 when Erlang only defines integer_to_list/1,2.
This will work:
-module(demo).
-export([swedish_date/0]).
swedish_date() ->
[YYYY,MM,DD] = tuple_to_list(date()),
string:substr(
integer_to_list(YYYY) ++
pad_string(integer_to_list(MM)) ++
pad_string(integer_to_list(DD))
).
pad_string(String) ->
if
length(String) == 1 -> '0' ++ String;
true -> String
end.
In addition to the parenthesis error on line 6, you also have an error on line 10 where yo use the form '0' instead of "0", so you define an atom rather than a string.
I understand you are doing this for educational purpose, but I encourage you to dig into erlang libraries, it is something you will have to do. For a common problem like this, it already exists function that help you:
swedish_date() ->
{YYYY,MM,DD} = date(), % not useful to transform into list
lists:flatten(io_lib:format("~2.10.0B~2.10.0B~2.10.0B",[YYYY rem 100,MM,DD])).
% ~X.Y.ZB means: uses format integer in base Y, print X characters, uses Z for padding
So I work with files, and I need to know the largest line in file X. Using Unix awk results in a Int that I'm looking for. But in Haskell how can I return that value and save it to a variable?
I tried define something with IO [Int] -> [Int]
maxline = do{system "awk ' { if ( length > x ) { x = length } }END{ print x }' filename";}
doesn't work cause:
Couldn't match expected type 'Int',against inferred type 'IO GHC.IO.Exception.ExitCode'
This is because the system action returns the exit status of the command you run which cannot be converted to Int. You should use the readProcess to get the commands output.
> readProcess "date" [] []
"Thu Feb 7 10:03:39 PST 2008\n"
Note that readProcess does not pass the command to the system shell: it runs it directly. The second parameter is where the command's arguments should go. So your example should be
readProcess "awk" [" { if ( length > x ) { x = length } }END{ print x }", "/home/basic/Desktop/li11112mp/textv"] ""
You can use readProcess to get another program's output. You will not be able to convert the resulting IO String into a pure String; however, you can lift functions that expect Strings into functions that expect IO Strings. My two favorite references for mucking about with IO (and various other monads) are sigfpe's excellent blog posts, You Could Have Invented Monads! (And Maybe You Already Have.) and The IO Monad for People who Simply Don't Care.
For this particular problem, I would strongly suggest looking into finding a pure-Haskell solution (that is, not calling out to awk). You might like readFile, lines, and maximumBy.