Hi,

I guess it is for brevity and to allow "(" output_expression_list ")"  = fcall(...);
Maybe it would be better to remove it and have equation include the case with output_expression_list on the left hand side.
You can add a ticket at http://trac.modelica.org with Modelica Specification as a component and point it out.

Cheers,
Adrian Pop/

Modelica specification has a separate definition for that case:

statement :

( component_reference ( ":=" expression | function_call_args )

| "(" output_expression_list ")" ":=" component_reference function_call_args 

| ...

Now when thinking of this, replacing output_expression_list with expression_list would allow (1,2,3)^(4,5,6,7,) which would not make much sense either.. Maybe that is just a forgotten legacy line for the function call case? I'll add that ticket and wait for smart people to resolve it

The rule you give is for statements, not equations.
I was talking about equations where left hand side is a multiple output and right hand side is a function call returning multiple outputs.
(1, 2, 3)^(4,5,6) makes sense if you think about it as tuples, so is actually equivalent to (1^4, 2^5, 3^6).

Cheers,
Adrian Pop/

That's only a rule for statements. For equations it is different... And I guess to make the grammar simpler those checks are not done.

And regardless, tuples "( ... )" are only allowed for function call results. A Modelica tool will not let it go unnoticed (except maybe during parsing; but that's a non-issue as most languages allow you to use syntax that is not really allowed later on).

Thanks, it is all starting to make sense now!

This example shows why the output_expression_list is actually useful:

model Test



function func

  input Real a;

  input Real b;

  output Real c;

  output Real d;

algorithm

  c := a*a;

  d := b+b;

end func;



  parameter Real e = 3;

  parameter Real f = 5;

  Real g;

equation

  (,g) = func(e,f);

end Test;

I'll comment this also to the bug report.