Suggestion:
Would it be possible to optionally allow for EOL markers in sublines, after the semi-colon, an EOL with no semi-colon would obviously be considered the end of the statement
A very simple example:
%t5%alShuffle:%ar%cb %ce;%t5%al Repeat:%ar%cb %ce
Could become:
%t5%alShuffle:%ar%cb %ce;
%t5%al Repeat:%ar%cb %ce
With some of the very complex syntax now appearing in wps's (long line lengths!), spotting errors can be difficult, able being able to split them makes them easier to read, and the 'line number' for the error given by the parser would be more specific as to the exact position of the failure.