Ping.
On Thu, 16 Nov 2017, Nicolas Pitre wrote:
> Since commit 31847b67bec0 ("kconfig: allow use of relations other than
> (in)equality") it is possible to use relational operators in Kconfig
> statements. However, those operators give unexpected results when
> applied to bool/tristate values:
>
> (n < y) = y (correct)
> (m < y) = y (correct)
> (n < m) = n (wrong)
>
> This happens because relational operators process bool and tristate
> symbols as strings and m sorts before n. It makes little sense to do a
> lexicographical compare on bool and tristate values though.
>
> Documentation/kbuild/kconfig-language.txt states that expression can have
> a value of 'n', 'm' or 'y' (or 0, 1, 2 respectively for calculations).
> Let's make it so for relational comparisons with bool/tristate
> expressions as well and document them. If at least one symbol is an
> actual string then the lexicographical compare works just as before.
>
> Signed-off-by: Nicolas Pitre <[email protected]>
>
> diff --git a/Documentation/kbuild/kconfig-language.txt
> b/Documentation/kbuild/kconfig-language.txt
> index 262722d886..c4a293a03c 100644
> --- a/Documentation/kbuild/kconfig-language.txt
> +++ b/Documentation/kbuild/kconfig-language.txt
> @@ -200,10 +200,14 @@ module state. Dependency expressions have the following
> syntax:
> <expr> ::= <symbol> (1)
> <symbol> '=' <symbol> (2)
> <symbol> '!=' <symbol> (3)
> - '(' <expr> ')' (4)
> - '!' <expr> (5)
> - <expr> '&&' <expr> (6)
> - <expr> '||' <expr> (7)
> + <symbol1> '<' <symbol2> (4)
> + <symbol1> '>' <symbol2> (4)
> + <symbol1> '<=' <symbol2> (4)
> + <symbol1> '>=' <symbol2> (4)
> + '(' <expr> ')' (5)
> + '!' <expr> (6)
> + <expr> '&&' <expr> (7)
> + <expr> '||' <expr> (8)
>
> Expressions are listed in decreasing order of precedence.
>
> @@ -214,10 +218,13 @@ Expressions are listed in decreasing order of
> precedence.
> otherwise 'n'.
> (3) If the values of both symbols are equal, it returns 'n',
> otherwise 'y'.
> -(4) Returns the value of the expression. Used to override precedence.
> -(5) Returns the result of (2-/expr/).
> -(6) Returns the result of min(/expr/, /expr/).
> -(7) Returns the result of max(/expr/, /expr/).
> +(4) If value of <symbol1> is respectively lower, greater, lower-or-equal,
> + or greater-or-equal than value of <symbol2>, it returns 'y',
> + otherwise 'n'.
> +(5) Returns the value of the expression. Used to override precedence.
> +(6) Returns the result of (2-/expr/).
> +(7) Returns the result of min(/expr/, /expr/).
> +(8) Returns the result of max(/expr/, /expr/).
>
> An expression can have a value of 'n', 'm' or 'y' (or 0, 1, 2
> respectively for calculations). A menu entry becomes visible when its
> diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
> index cbf4996dd9..8cee597d33 100644
> --- a/scripts/kconfig/expr.c
> +++ b/scripts/kconfig/expr.c
> @@ -893,7 +893,10 @@ static enum string_value_kind expr_parse_string(const
> char *str,
> switch (type) {
> case S_BOOLEAN:
> case S_TRISTATE:
> - return k_string;
> + val->s = !strcmp(str, "n") ? 0 :
> + !strcmp(str, "m") ? 1 :
> + !strcmp(str, "y") ? 2 : -1;
> + return k_signed;
> case S_INT:
> val->s = strtoll(str, &tail, 10);
> kind = k_signed;
>
