gr_modtoolgives some options of block types while creating a new block. The options are as follow:
('sink', 'source', 'sync', 'decimator', 'interpolator', 'general', 'tagged_stream', 'hier', 'noblock')
I have explored those options but I have not found any one related to pure Message Passing blocks
Is there any tool similar or option on gr_modtool for pure Message Passing blocks?
Currently it looks like pure message blocks are not directly supported by gr_modtool. There is a pretty easy work around, just create a sink or source block, set all the inputs to "None" and set up the message handlers/posters as if you had created a pure message block. You can then edit the XML definition as desired.
Related
Is it possible to access arguments/parameters passed to an emitted event within an inline / in-template handler? Something like:
<component #some-event="someObject.field = $arguments[0]"></component
What I'm trying to do exactly is assign a value to an object in the scope. I know I can create a method to do that and use it as a handler for the event but I was wondering if this could work as an inline statement.
It is not $arguments[0], but just arguments[0] (without the $). I am surprised that it actually works in the inline handler. So the following code is valid and will work:
<component #some-event="someObject.field = arguments[0]"></component>
The docs for Methods in Inline Handlers specifies $event as a special variable that gets the first parameter passed via event. I have always used it till now.
After reading your question, a bit more research led me to this reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments
It seems every javascript function has a local variable called arguments, which is used when a function is expected to get variable number of arguments.
Using arguments[] as inline statements is definitely possible, but not documented anywhere in the context of vue.js framework. On the other hand, if you use $event in inline handler for events, it feels safer as it is documented clearly and will not break in a future version of Vue.js
Sample usage for $event:
<component #some-event="someObject.field = $event"></component>
There is something that not many people know.
Inline handler besides the $event has access to arguments.
For example I was using v-dropzone which is passing many arguments (e.g. file, response).
By using
<v-dropzone #some-event="callMethod($event, 'some other arg')" >
will catch only the first argument.
So the solution was:
<v-dropzone #some-event="callMethod(arguments, 'some other arg')" >
While modifying an existing program's CASE statement, I had to add a second block where some logic is repeated to set NetWeaver portal settings. This is done by setting values in a local variable, then assigning that variable to a Changing parameter. I copied over the code and did a Pretty Print, expecting to compiler to complain about the unknown variable. To my surprise however, this code actually compiles just fine:
CASE i_actionid.
WHEN 'DOMIGO'.
DATA: ls_portal_actions TYPE powl_follow_up_sty.
CLEAR ls_portal_actions.
ls_portal_actions-bo_system = 'SAP_ECC_Common'.
" [...]
c_portal_actions = ls_portal_actions.
WHEN 'EBELN'.
ls_portal_actions-bo_system = 'SAP_ECC_Common'.
" [...]
C_PORTAL_ACTIONS = ls_portal_actions.
ENDCASE.
As I have seen in every other programming language, the DATA: declaration in the first WHEN statement should be encapsulated and available only inside that switch block. Does SAP ignore this encapsulation to make that value available in the entire CASE statement? Is this documented anywhere?
Note that this code compiles just fine and double-clicking the local variable in the second switch takes me to the data declaration in the first. I have however not been able to test that this code executes properly as our testing environment is down.
In short you cannot do this. You will have the following scopes in an abap program within which to declare variables (from local to global):
Form routine: all variables between FORM and ENDFORM
Method: all variables between METHOD and ENDMETHOD
Class - all variables between CLASS and ENDCLASS but only in the CLASS DEFINITION section
Function module: all variables between FUNCTION and ENDFUNCTION
Program/global - anything not in one of the above is global in the current program including variables in PBO and PAI modules
Having the ability to define variables locally in a for loop or if is really useful but unfortunately not possible in ABAP. The closest you will come to publicly available documentation on this is on help.sap.com: Local Data in the Subroutine
As for the compile process do not assume that ABAP will optimize out any variables you do not use it won't, use the code inspector to find and remove them yourself. Since ABAP works the way it does I personally define all my variables at the start of a modularization unit and not inline with other code and have gone so far as to modify the pretty printer to move any inline definitions to the top of the current scope.
Your assumption that a CASE statement defines its own scope of variables in ABAP is simply wrong (and would be wrong for a number of other programming languages as well). It's a bad idea to litter your code with variable declarations because that makes it awfully hard to read and to maintain, but it is possible. The DATA statements - as well as many other declarative statements - are only evaluated at compile time and are completely ignored at runtime. You can find more information about the scopes in the online documentation.
The inline variable declarations are now possible with the newest version of SAP Netweaver. Here is the link to the documentation DATA - inline declaration. Here are also some guidelines of a good and bad usage of this new feature
Here is a quote from this site:
A declaration expression with the declaration operator DATA declares a variable var used as an operand in the current writer position. The declared variable is visible statically in the program from DATA(var) and is valid in the current context. The declaration is made when the program is compiled, regardless of whether the statement is actually executed.
Personally have not had time to check it out yet, because of lack of access to such system.
I'm currently working on my first major project in clojure and have run into a question regarding coding style and the most "clojure-esque" way of doing something. Basically I have a function I'm writing which takes in a data structure and a template that the function will try to massage the data structure into. The template structure will look something like this:
{
:key1 (:string (:opt :param))
:key2 (:int (:opt :param))
:key3 (:obj (:tpl :template-structure))
:key4 (:list (:tpl :template-structure))
}
Each key is an atom that will be searched for in the given data structure, and it's value will be attempted to be matched to the type given in the template structure. So it would look for :key1 and check that it's a string, for instance. The return value would be a map that has :key1 pointing to the value from the given data structure (the function could potentially change the value depending on the options given).
In the case of :obj it takes in another template structure, and recursively calls itself on that value and the template structure, and places the result from that in the return. However, if there's an error I want that error returned directly.
Similarly for lists I want it to basically do a map of the function again, except in the case of an error which I want returned directly.
My question is what is the best way to handle these errors? Some simple exception handling would be the easiest way, but I feel that it's not the most functional way. I could try and babysit the errors all the way up the chain with tons of if statements, but that also doesn't seem very sporting. Is there something simple I'm missing or is this just an ugly problem?
You might be interested in schematic, which does pretty similar stuff. You can see how it's used in the tests, and the implementation.
Basically I defined an error function, which returns nil for correctly-formatted data, or a string describing the error. Doing it with exceptions instead would make the plumbing easier, but would make it harder to get the detailed error messages like "[person: [first_name: expected string, got integer]]".
Aside from getting any real work done, I have an itch. My itch is to write a view engine that closely mimics a template system from another language (Template Toolkit/Perl). This is one of those if I had time/do it to learn something new kind of projects.
I've spent time looking at CoCo/R and ANTLR, and honestly, it makes my brain hurt, but some of CoCo/R is sinking in. Unfortunately, most of the examples are about creating a compiler that reads source code, but none seem to cover how to create a processor for templates.
Yes, those are the same thing, but I can't wrap my head around how to define the language for templates where most of the source is the html, rather than actual code being parsed and run.
Are there any good beginner resources out there for this kind of thing? I've taken a ganer at Spark, which didn't appear to have the grammar in the repo.
Maybe that is overkill, and one could just test-replace template syntax with c# in the file and compile it. http://msdn.microsoft.com/en-us/magazine/cc136756.aspx#S2
If you were in my shoes and weren't a language creating expert, where would you start?
The Spark grammar is implemented with a kind-of-fluent domain specific language.
It's declared in a few layers. The rules which recognize the html syntax are declared in MarkupGrammar.cs - those are based on grammar rules copied directly from the xml spec.
The markup rules refer to a limited subset of csharp syntax rules declared in CodeGrammar.cs - those are a subset because Spark only needs to recognize enough csharp to adjust single-quotes around strings to double-quotes, match curley braces, etc.
The individual rules themselves are of type ParseAction<TValue> delegate which accept a Position and return a ParseResult. The ParseResult is a simple class which contains the TValue data item parsed by the action and a new Position instance which has been advanced past the content which produced the TValue.
That isn't very useful on it's own until you introduce a small number of operators, as described in Parsing expression grammar, which can combine single parse actions to build very detailed and robust expressions about the shape of different syntax constructs.
The technique of using a delegate as a parse action came from a Luke H's blog post Monadic Parser Combinators using C# 3.0. I also wrote a post about Creating a Domain Specific Language for Parsing.
It's also entirely possible, if you like, to reference the Spark.dll assembly and inherit a class from the base CharGrammar to create an entirely new grammar for a particular syntax. It's probably the quickest way to start experimenting with this technique, and an example of that can be found in CharGrammarTester.cs.
Step 1. Use regular expressions (regexp substitution) to split your input template string to a token list, for example, split
hel<b>lo[if foo]bar is [bar].[else]baz[end]world</b>!
to
write('hel<b>lo')
if('foo')
write('bar is')
substitute('bar')
write('.')
else()
write('baz')
end()
write('world</b>!')
Step 2. Convert your token list to a syntax tree:
* Sequence
** Write
*** ('hel<b>lo')
** If
*** ('foo')
*** Sequence
**** Write
***** ('bar is')
**** Substitute
***** ('bar')
**** Write
***** ('.')
*** Write
**** ('baz')
** Write
*** ('world</b>!')
class Instruction {
}
class Write : Instruction {
string text;
}
class Substitute : Instruction {
string varname;
}
class Sequence : Instruction {
Instruction[] items;
}
class If : Instruction {
string condition;
Instruction then;
Instruction else;
}
Step 3. Write a recursive function (called the interpreter), which can walk your tree and execute the instructions there.
Another, alternative approach (instead of steps 1--3) if your language supports eval() (such as Perl, Python, Ruby): use a regexp substitution to convert the template to an eval()-able string in the host language, and run eval() to instantiate the template.
There are sooo many thing to do. But it does work for on simple GET statement plus a test. That's a start.
http://github.com/claco/tt.net/
In the end, I already had too much time in ANTLR to give loudejs' method a go. I wanted to spend a little more time on the whole process rather than the parser/lexer. Maybe in version 2 I can have a go at the Spark way when my brain understands things a little more.
Vici Parser (formerly known as LazyParser.NET) is an open-source tokenizer/template parser/expression parser which can help you get started.
If it's not what you're looking for, then you may get some ideas by looking at the source code.
I want to expose the functionality of an SAP program (transaction) as a BAPI.
I need to call a report and supply range filters such that the GUI is bypassed.
Does anyone have a working example of the SUBMIT ... WITH ... ABAP construct, or other suggestions on how to accomplish what I need to do?
Here is a working example:
SUBMIT SAPF140
TO SAP-SPOOL "optional"
SPOOL PARAMETERS print_parameters "optional"
WITHOUT SPOOL DYNPRO "optional (hides the spool pop-up)"
VIA JOB jobname NUMBER l_number "optional"
AND RETURN "optional - returns to the calling prog"
WITH EVENT = REVENT
WITH BUKRS IN RBUKRS
WITH BELNR IN lRBELNR
WITH GJAHR IN RGJAHR
WITH USNAM = SY-UNAME
WITH DATUM = SAVE_DATUM
WITH UZEIT = SAVE_UZEIT
WITH DELDAYS = RDELDAYS
WITH KAUTO = 'X'
WITH RPDEST = SAVE_PDEST
WITH TITLE = TITLE.
All the "WITH" statements relates to selection fields on the called program where I use = it is a PARAMETER statement (single field), where I use IN it is a SELECT_OPTIONS statement (range)
Here is a simple example of how to fill a range:
REFRESH lrbelnr.
lrbelnr-sign = 'I'.
lrbelnr-option = 'EQ'.
lrbelnr-low = HBKORM-belnr.
CLEAR lrbelnr-high.
append lrbelnr.
If you want to suppress this functionality as a BAPI you have to wrap the functionality in a Remote Function Call (RFC) module. Just implement a RFC function module. Depending how the report is implemented, it may use ABAP objects, which can also be called from your RFC implementation. Given that case you have a quite good solution. Whenever the report is adjusted, also your BAPI will reflect the changes. In case it's a standard programm from SAP which cannot be wrapped, think about copying it into your namespace and adjusting it. Nevertheless this might give some hassle, when SAP performs an update via Support Package Stack and you won't realize it. The output of the two methods is different. Apart from that, if you want to call it from outside, there is nothing else possible than implementing a RFC module.
A submit report can not return the values outside. Reports are always only for GUI functionalities and not for exchanging data. In case your report uses select options, you somehow have to implement this feature "by hand" in your RFC, as this statements can not be used inside RFC modules. I would generally try to rework the report, modularize it and put the selection information in a central class or maybe another function module wich can be called from the report and your BAPI function module. The filters you are talking about can not be implemented in RFCs automatically. You have to implement those ranges manually. The warning which comes up cannot be suppressed, if you do a RFC call from a remote system and the popup with the warning comes up you'll end with a shortdump. Therefore, you have to rework the report and to re-implement it for your needs.
If you are just looking for bypassing it via job scheduling, create a variant and schedule the report with that variant but I suppose that's not the solution you're looking for.
You can use inbuilt BAPI also just write "Range" and press F4.
You can wrap your report in an BATCH INPUT session and execute it inside a function. The only drawback is that you need to rewrite the BATCH INPUT every time you change the report.