user: Do you know the PLC programming language called Structured Text (ST)?
I'm want to learn more about it.

assistant: Structured Text (ST) is one of the five IEC 61131-3 standard PLC (Programmable Logic Controller) programming languages. It is a high-level, text-based language similar to Pascal and is used for creating and maintaining automation and control processes in industrial applications. ST is designed for ease of use, readability, and flexibility, allowing engineers to create complex control logic using familiar programming constructs.

Here's an overview of some key concepts and syntax in Structured Text:

 1. Variables and data types: ST supports various data types, such as BOOL, INT, UINT, DINT, UDINT, REAL, and TIME. You can declare variables using the VAR, VAR_INPUT, VAR_OUTPUT, and VAR_IN_OUT blocks.

Example:

```css
VAR
    x : INT := 0;
    y : REAL;
END_VAR
```
2.  Control structures: ST supports common programming control structures, including IF-THEN-ELSE, CASE, WHILE, REPEAT, and FOR loops.

Example (IF-THEN-ELSE):

```css
IF x > 10 THEN
    y := 5 * x;
ELSE
    y := 2 * x;
END_IF
```

Example (FOR loop):


```bash
FOR i := 1 TO 10 DO
    sum := sum + i;
END_FOR
```

 3.  Functions and function blocks: Functions and function blocks are reusable pieces of code that can be called from the main program or other functions/function blocks. Functions have a single output, while function blocks can have multiple outputs and retain their internal state between calls.

Example (Function):

```sql
FUNCTION Add : REAL
VAR_INPUT
    a : REAL;
    b : REAL;
END_VAR
    Add := a + b;
END_FUNCTION
```

Example (Function Block):

```css
FUNCTION_BLOCK Integrator
VAR_INPUT
    input : REAL;
END_VAR
VAR_OUTPUT
    output : REAL;
END_VAR
VAR
    sum : REAL := 0;
END_VAR
    sum := sum + input;
    output := sum;
END_FUNCTION_BLOCK
```

To get started with Structured Text, you can follow these steps:

1.  Familiarize yourself with the syntax and constructs of the language.
2. Learn about PLC programming concepts, such as memory organization, I/O handling, and communication protocols.
3. Choose a PLC programming software that supports Structured Text, such as CODESYS, TIA Portal (Siemens), or Studio 5000 (Rockwell Automation).
4. Practice creating simple programs and gradually progress to more complex applications.
5. Study existing ST code examples and projects to understand how real-world applications are developed.

As you gain experience with Structured Text, you'll be able to develop and maintain complex automation and control processes in various industrial settings.

user: Can the indentation be done with tabs in ST?  If so, please rewrite the examples with tabs so I can copy/paste it with them.

assistant: Yes, Sublime Text can use tabs for indentation. Here are the examples rewritten with tabs:

Example 1:

```
def greet(name):
	if len(name) > 0:
		print("Hello, " + name + "!")
	else:
		print("Hello there!")
```

Example 2:

```
for i in range(1, 11):
	print("\t" + str(i))
```

Example 3:

```
def calculate_sum(numbers):
	total = 0
	for num in numbers:
		total += num
	return total
```

In the above examples, each level of indentation is represented by a single tab character. You can copy and paste these examples into Sublime Text and use tabs for indentation. However, it's important to note that using tabs and spaces for indentation can sometimes cause issues with consistency and formatting, so it's a good idea to choose one method and stick to it throughout your code.