Jison not assuming correct grammar about jison

[GerHobbelt]

For the AND and OR tokens in your grammar rules, your rules' action code takes their value (condition rule: $$ = ... + $2 + ...; where $2 references the AND (or OR) token in that subrule. The value for the lexed token is its lexed string ('e' or 'ou' in your case) unless you specifically set it to something else.

Two ways about it (not tested; YMMV as this should work for the jison-gho fork at least, but not sure about jison itself):

1:

$$ = ... + 'AND' + ...; i.e. hardcoding the AND and OR strings in the grammar rules' action blocks.

2:

augment the lexer to return different token values (which will then be used by the $2 references):

e      yytext = "AND";
        return 'AND'
ou    yytext = "OR";
        return 'OR'

Second approach is cleaner IMO (and more akin to what you'ld do when doing this in classic lex / flex)