Embed Directive in Modelica

Here’s the translation of the Go code to Modelica, formatted in Markdown suitable for Hugo:

Our example demonstrates how to include external files in a Modelica model. While Modelica doesn’t have a direct equivalent to the embed directive, we can use the Modelica.Utilities.Files package to read external files.

model EmbedExample
  import Modelica.Utilities.Files;
  import Modelica.Utilities.Streams;

  String fileString;
  String fileByte;
  
  function readFile
    input String fileName;
    output String content;
  algorithm
    content := Files.readFile(fileName);
  end readFile;

equation
  fileString = readFile("folder/single_file.txt");
  fileByte = readFile("folder/single_file.txt");

algorithm
  Streams.print(fileString);
  Streams.print(fileByte);
  
  Streams.print(readFile("folder/file1.hash"));
  Streams.print(readFile("folder/file2.hash"));
end EmbedExample;

In this Modelica example:

1. We import the necessary utilities for file operations.

2. We define a readFile function that reads the contents of a file and returns it as a string.

3. In the equation section, we read the contents of single_file.txt into both fileString and fileByte. In Modelica, there’s no distinction between string and byte array for text files.

4. In the algorithm section, we print the contents of the files.

To run this example, you would need to create the necessary files:

$ mkdir -p folder
$ echo "hello modelica" > folder/single_file.txt
$ echo "123" > folder/file1.hash
$ echo "456" > folder/file2.hash

Then, you can simulate the model in your Modelica environment. The output would be:

hello modelica
hello modelica
123
456

Note that Modelica doesn’t have a built-in mechanism to embed files at compile-time like Go does. Instead, we read the files at runtime. This approach is more flexible but might be slower for large files or frequent reads.

Also, error handling in this example is simplified. In a real-world application, you’d want to add proper error checking when reading files.