Range Over Built in Modelica

Based on the code and the explanation provided, here is the corresponding Modelica code:

Our first program will print the classic “hello world” message. Here’s the full source code.

model HelloWorld
  function printHelloWorld
    input String message;
  algorithm 
    print(message);
  end printHelloWorld;

  algorithm 
    printHelloWorld("hello world");
end HelloWorld;

To run the program, save the code in a .mo file and use the OpenModelica compiler omc to execute it:

$ omc HelloWorld.mo

We have successfully printed the “hello world” message using Modelica. Let’s learn more about the language by exploring more examples.

Here we use a loop to sum the numbers in an array. Arrays work like this too.

model SumArray
  Real nums[3] = {2, 3, 4};
  Real sum = 0;

  algorithm 
    for i in 1:size(nums, 1) loop
      sum := sum + nums[i];
    end for;

    print("sum: " + String(sum));
end SumArray;

The above code sums the array elements using a for loop and prints the result:

$ omc SumArray.mo
sum: 9

To iterate over arrays and get index and value for each entry, although Modelica does not have a direct way to ignore indices like _, you can simply access both.

model IndexValue
  Real nums[3] = {2, 3, 4};

  algorithm 
    for i in 1:size(nums, 1) loop
      if nums[i] == 3 then
        print("index: " + String(i - 1));
      end if;
    end for;
end IndexValue;

Output:

$ omc IndexValue.mo
index: 1

Modelica also allows iterating over key/value pairs in a dictionary-like way using records, but it’s more common to handle key-value arrays.

record KeyValue
  String key;
  String value;
end KeyValue;

model KeyValuePair
  KeyValue kvs[2] = {KeyValue("a", "apple"), KeyValue("b", "banana")};

  algorithm
    for i in 1:size(kvs, 1) loop
      print(kvs[i].key + " -> " + kvs[i].value);
    end for;
end KeyValuePair;

Output:

$ omc KeyValuePair.mo
a -> apple
b -> banana

To iterate over just the keys, one can simply access the key field of the record.

model KeysOnly
  KeyValue kvs[2] = {KeyValue("a", "apple"), KeyValue("b", "banana")};

  algorithm
    for i in 1:size(kvs, 1) loop
      print("key: " + kvs[i].key);
    end for;
end KeysOnly;

Output:

$ omc KeysOnly.mo
key: a
key: b

Iterating over strings requires accessing string characters individually.

model StringIteration
  String str = "go";

  algorithm
    for i in 1:length(str) loop
      print(String(i - 1) + " " + String(str[i]));
    end for;
end StringIteration;

Output:

$ omc StringIteration.mo
0 g
1 o

Now that we understand how to perform these iterations in Modelica, let’s continue to explore more features of the language.

Recursion in Modelica

Pointers in Modelica

Learn X By Example

Title here

Range Over Built in Modelica