assignment in line decorators

Would it be possible to add conditional assignment to line decorators? For example, I can do option 1:
fcolor=message\match "<%w*>"
message=message\gsub "<%->", fcolor if fcolor

Or option 2:
message=message\gsub "<%->", fcolor if (->fcolor=message\match "<%w*>" )!

But option 2 creates an anonymous function. The following would be better:

message=message\gsub "<%->", fcolor if fcolor=message\match "<%w*>"
compiled to the same output as
if fcolor=message\match "<%w*>" then message=message\gsub "<%->", fcolor