Transform Robot Framework pre-v3.1 for-loops to the new syntax

Robot Framework adds a new syntax for the for loops: the starting keyword (FOR) is no longer prefixed with a colon, the block isn't marked with slashes - \, and it must end with the END keyword.

This script can be used to transform source files from the "old style" to the new one.

Usage

• Prerequisite - needs python version >= 3.6.
• The target file(s) is modified in-place - so it must be in version control (preferable), or use the script on backup copies.

The script accepts a single argument - the target to be modified; the argument supports file names wildcard; samples:

change_rf_for.py directory/suite.robot     # modify a single file
change_rf_for.py directory/*.robot         # modify all files ending with robot
change_rf_for.py directory/**/*.robot      # modify all files ending with robot, in all sub-directories

Modifications

A source with this content:

  No Operation
  :FOR  ${animal}  IN  cat  dog
  \    Log ${animal}
  \    Log  2nd keyword
  
  Log    Outside the loop
  
      :FOR  ${counter}  IN RANGE    1    5      # custom block indent
        #   a comment in the loop
            \    Log   It's ${counter}
  :FOR  ${value}    IN    @{itterable}      # two loops with no lines b/n them
  \    Run Keywords        Log     The value is ${value}
         ...         AND   Log     2nd keyword
  Log   this is a line just after the loop, no lines b/n it and the FOR block
  
  :FOR  ${animal}  IN  cat  dog
  \    Log ${animal}
       # there is an empty line before the next in-block line
       # e.g. a "broken-up" block
  
  \    Log  2nd keyword
  \    Log  3rd keyword
  
  ${answer}=        Evaluate  42

, will be transformed to:

  No Operation
  FOR  ${animal}  IN  cat  dog
       Log ${animal}
       Log  2nd keyword
  END
  
  Log    Outside the loop
  
      FOR  ${counter}  IN RANGE    1    5      # custom block indent
        #   a comment in the loop
                 Log   It's ${counter}
      END
  FOR  ${value}    IN    @{itterable}      # two loops with no lines b/n them
       Run Keywords        Log     The value is ${value}
         ...         AND   Log     2nd keyword
  END
  Log   this is a line just after the loop, no lines b/n it and the FOR block
  
  FOR  ${animal}  IN  cat  dog
       Log ${animal}
       # there is an empty line before the next in-block line
       # e.g. a "broken-up" block
  
       Log  2nd keyword
       Log  3rd keyword
  END
  
  ${answer}=        Evaluate  42

The script will rewrite only the files where it detects a for loop, printing on the console the outcome for each analyzed file:

INFO: suites/file_x.robot was modified.
INFO: suites/file_y.robot was not modified.

Other

A line that is after a :FOR and doesn't start with \, ... or # (or is not an empty line) is considered outside of the loop block, and this is the place where the END is added to close the loop.

The script prints to the console a warning for all lines that start with \, but are not in a for block.
A possible reason for that to happen is because of a bug in the script ?\_(?)_/? - so monitor its output, and correct such issues manually:

WARN: 	suites/file_x.robot:7 has an orphaned "\" 
INFO: suites/file_x.robot was modified.