String Functions in Modelica

In Modelica, string manipulation is typically done using built-in functions or through external C functions. Here’s an example showcasing some string operations in Modelica:

model StringFunctions
  import Modelica.Utilities.Strings.*;

  function p
    input String str;
  algorithm
    Modelica.Utilities.Streams.print(str);
  end p;

equation
  when initial() then
    p("Contains:  " + String(find("test", "es") > 0));
    p("Count:     " + String(countOccurrences("test", "t")));
    p("HasPrefix: " + String(startsWith("test", "te")));
    p("HasSuffix: " + String(endsWith("test", "st")));
    p("Index:     " + String(find("test", "e")));
    p("Join:      " + join({"a", "b"}, "-"));
    p("Repeat:    " + repeat("a", 5));
    p("Replace:   " + replace("foo", "o", "0"));
    p("Replace:   " + replace("foo", "o", "0", 1));
    p("Split:     " + String(split("a-b-c-d-e", "-")));
    p("ToLower:   " + toLowerCase("TEST"));
    p("ToUpper:   " + toUpperCase("test"));
  end when;
end StringFunctions;

This example demonstrates various string operations in Modelica. Note that Modelica doesn’t have a dedicated string manipulation package like Go’s strings. Instead, we use functions from the Modelica.Utilities.Strings package.

Here’s a breakdown of the string functions used:

1. find: Searches for a substring within a string.
2. countOccurrences: Counts the number of occurrences of a substring.
3. startsWith and endsWith: Check if a string starts or ends with a given substring.
4. join: Concatenates an array of strings with a separator.
5. repeat: Repeats a string a specified number of times.
6. replace: Replaces occurrences of a substring with another string.
7. split: Splits a string into an array of substrings based on a separator.
8. toLowerCase and toUpperCase: Convert a string to lowercase or uppercase.

To run this model, you would typically use a Modelica simulation environment. The output would be similar to the Go example, showing the results of various string operations.

Note that some operations, like Index, are simulated using the find function, as Modelica doesn’t have a direct equivalent. Also, Modelica’s string handling is generally less extensive than Go’s, so some operations might require more complex implementations or external functions for advanced use cases.