public variable in function without input/output

[thorade]

Dymola check complains about this code:

function myFun1
  input Real x;
  output Real y;
  Real z = 4;
algorithm 
  y := x*z;
end myFun1;

but not about this:

function myFun2
  input Real x;
  output Real y;
  constant Real z = 4;
algorithm 
  y := x*z;
end myFun2;

and also not about this:

function myFun2
  input Real x;
  output Real y;
  parameter Real z = 4;
algorithm 
  y := x*z;
end myFun2;

Is it allowed to have any variable without input/output in the public section? Why would it be allowed if variability is reduced to constant or parameter? For another discussion about parameters in functions, see #1594.

[henrikt-ma]

While not crystal clear, this restriction from 12.2 seems to imply that all of the functions above are illegal:

Each input formal parameter of the function must be prefixed by the keyword input, and each result formal parameter by the keyword output. All public variables are formal parameters.

I'd find it more clear if it was written like this instead:

… Only input and output formal parameters are allowed in the function's public variable section.

[qlambert-pro]

The implication of the beginning of section 12.4.4 leads me to the same conclusion as Henrik.

Components in a function can be divided into three groups:

• Public components which are input formal parameters.
• Public components which are output formal parameters.
• Protected components which are local variables, parameters, or constants.

[henrikt-ma]

The following statement in 12.9 also confirms the current intention:

Components in the public part of an external function declaration shall be declared either as input or output.
[This is just as for any other function. The components in the protected part allow local variables for temporary storage to be declared.]

[HansOlsson]

I agree that there doesn't seem to be anything special for such parameter/constant in function.

[HansOlsson]

Function public components must be input or output, check MSL.

Agreement.

[henrikt-ma]

This wasn't only a tool issue; had the could actually also have been more clear, see #2730 (comment). Should I prepare a PR?

[HansOlsson]

This wasn't only a tool issue; had the could actually also have been more clear, see #2730 (comment). Should I prepare a PR?

I prepared one.