Hi,
since we still have a lot of customers using Automation Basic I created a conversion script to Structure Text. This script can be selected from migration tool drop down. If you find any issues with this script please create an issue on GitHub with a detailed description of the problem.
Intended use
This script is intended to convert Automation Basic code to Structured Text code. It can be used as a starting point for porting existing Automation Basic code to Structured Text. However, the generated Structured Text code may require manual adjustments and testing to ensure it works correctly in the target environment.
What will be converted
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Comments of type (* … *) are converted to // comments in Structured Text.
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Semicolons are added at the end of each statement in Structured Text.
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Keywords are converted from Automation Basic syntax to Structured Text syntax. For example, if ... then ... else ... endif is converted to IF ... THEN ... ELSE ... END_IF.
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Lowercase keywords are converted to uppercase keywords in Structured Text.
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Hex and binary literals are converted to Structured Text format. For example, $FF is converted to 16#FF and %1010 is converted to 2#1010.
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Convert select statements from Automation Basic to case statements in Structured Text. The select states must be defined with constant values, otherwise the compiler will raise an error for non-constant case values.
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Convert loop statements from Automation Basic to for statements in Structured Text.
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Convert case statements from Automation Basic to case statements in Structured Text.
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Math functions INC and DEC are converted to + 1 and - 1 respectively.
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Assignment operator = is converted to := in Structured Text.
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EXITIF statements are converted to IF … THEN … END_IF statements with a RETURN statement inside.
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Function block calls are converted to Structured Text syntax.
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String assignments are converted to Structured Text syntax if variable type can be identified.
Usage
Call the script with an complete Automation Studio project folder as argument. The script will search for all .ab files in the folder and its subfolders and convert them to .st files. You can also call the script with a single .ab file as argument to convert only that file.
Example command line usage:
python ab_2_st_converter.py path/to/project_or_file
Command-Line Options
The script supports various command-line switches to disable specific conversion functions. This can be useful when certain conversions are not desired or when you want to run conversions incrementally.
Disabling Conversion Functions
| Switch | Description |
|--------|-------------|
| --no-manual | Disable manual fix notices for unsupported keywords (GOTO, type casts) |
| --no-comment | Disable comment conversion (block comments (* *) to line comments //) |
| --no-keywords | Disable keyword replacements (e.g., ENDIF → END_IF) |
| --no-uppercase | Disable uppercase conversion for keywords (e.g., true → TRUE) |
| --no-numbers | Disable number format conversion (e.g., $FF → 16#FF, %1010 → 2#1010) |
| --no-select | Disable SELECT/STATE/WHEN/NEXT to CASE transformation |
| --no-loop | Disable LOOP/ENDLOOP to FOR/END_FOR conversion |
| --no-math | Disable INC/DEC math function conversion |
| --no-exitif | Disable EXITIF to IF...THEN...EXIT...END_IF conversion |
| --no-semicolon | Disable automatic semicolon insertion at end of statements |
| --no-functionblocks | Disable function block syntax fix (FUB removal) |
| --no-string-adr | Disable conditional ADR wrapping for string assignments |
| --no-string-adr-whitelist | Disable ADR wrapping in whitelisted function arguments (strcpy, memcpy, etc.) |
| --no-equals | Disable = to := assignment operator conversion |
Examples
Convert a project with all default conversions:
python ab_2_st_converter.py path/to/project
Convert a file but skip semicolon insertion and uppercase conversion:
python ab_2_st_converter.py path/to/file.ab --no-semicolon --no-uppercase
Convert a project but disable all string-related ADR conversions:
python ab_2_st_converter.py path/to/project --no-string-adr --no-string-adr-whitelist
Show help with all available options:
python ab_2_st_converter.py --help
Edge case
There are a few Automation Basic constructs that can not be converted automatically to Structured Text. If the conversion script encounters these constructs, it will add a comment starting with ### CONVERSION ERROR ###. Search for these comments after conversion to identify code that requires manual intervention. Below is a list of known corner cases with an explanation and an example code snippet.
Inline function block calls
In Automation Basic you can call function blocks inline as part of an expression. For example:
TON(diff_err_pos,time,diff_str_pos,dif_pos);
This type of call is not supported in Structured Text. You have to create an instance of the function block and call it separately:
my_ton_instance(IN := diff_err_pos, PT := time);
dif_pos := my_ton_instance.Q;
Since the script can not determine the name of the function block instance during conversion, this code can not be converted automatically.
String conversion
In Automation Basic the address of a string and the string itself are interchangeable. For example, you can assign a string variable to another string variable like this:
str_value = 'Hello World'
The variable str_value can be of type STRING or of type UDINT. Both assignments are valid. Structure Text is more strict about types. You have to use the ADR function to get the address of a string:
str_value := 'Hello World'; // str_value must be of type STRING
udint_value := ADR('Hello World'); // udint_value must be of type UDINT
The script will try to identify the variable type and convert the code accordingly. However, if the variable type cannot be determined during conversion this code can not be converted automatically.
Variable casting
In Automation Basic you can cast variables by using the datatype as a function like this:
time_diff := REAL(fub_timebase)*1e-6;
In Structured Text you have to use a cast function that considers the datatype your converting from:
time_diff := DINT_TO_REAL(fub_timebase, REAL) * 1e-6;
Since the source datatype cannot be determined during conversion, this code can not be converted automatically.
Loop without condition
This code snippet can not be converted automatically. Use REPEAT…END_REPEAT or WHILE…END_WHILE instead.
loop
exitif (X < param[i+2]) or (i>=((2*n)-4))
i = i + 2
endloop
GOTO statements
GOTO statements are not supported in Structured Text. You have to refactor the code to use structured control flow instead.
Migrating from AS4 to AS6 can be challenging, and this tool has the potential to make that process much smoother. But for it to be truly effective, we need your input! As Stephan mentioned, sharing the issues you encounter during migration is already an incredibly valuable. Every real-world case helps us improve the script and make it more robust for everyone.