I am calling "idmef_criteria_new_from_string" for
a few strings. Here are my expressions:

alert.classification.text = "whatever" 
alert. =
alert.classification.text = "whatever" 
alert.classification.text = "whatever" 

Note, that the first, third and 4th expressions
are valid (and all the same), the second one is
invalid.

Calling idmef_criteria_new_from_string with the
first string returns 0, ok.
The second expression returns an error, saying
"syntax error". Ok.
But now on the third one I still get an error:
"syntax error". It seems there is some state
left in the lex parsing of the string???
This does not happen if I modify the second
string to

"alert. = bla" 

which is still invalid (gives

the third string is parsed ok...