Re: [PATCH 3/5] c++: improvements on symbol kinds

[Akim Demaille]

> Le 15 avr. 2020 à 18:15, Hans Åberg <address@hidden> a écrit :
>>>> In retrospect, it would have been better to have it named "token_type", 
>>>> and "stack_symbol_type" would have been "symbol_type".
>>> 
>>> Maybe so. I only need the symbol value for the return to the parser from 
>>> the lexer, and mostly, they are symbol constants (tokens), but I am not 
>>> sure they always have to be.
>> 
>> So that's the kind.
> 
> I think it is unkind! :-) The word “kind” does not seem to be in line with 
> any C++ lingo at least.

The parser is fed with tokens by yylex.  A lexeme such as "123" in an 
arithmetical expression, has:

- a kind, NUMBER.  That coincides with what people refer to as a "token" when 
they talk about the grammar.

- a value, the int 100 + 20 + 3.

- a location, from Line 1 Col 1 to Line 1 Col 4 (excluded)

The type of the kind is token_kind_type, the type of the value is value_type, 
and the type of the location is location_type.  The type of the kind is not 
kind_type, because we actually deal with two kinds, so we must be clearer.  But 
there's only one concept of value_type and one of location_type.

And token_type denotes the type which is a triple: token_kind_type, value_type, 
location_type.

yylex returns the kind, and takes pointers to yylval (value) and yylloc 
(location).

Cheers!