diff options
| author | Nicolas Pitre <nicolas.pitre@linaro.org> | 2017-11-16 20:06:39 -0500 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-01-06 02:31:23 +0900 |
| commit | 9059a3493efea6492451430c7e2fa0af799a2abb (patch) | |
| tree | bc3011bb806742c6b1f2f4d8b13692aebb51a844 /Documentation | |
| parent | cfe17c9bbe6a673fdafdab179c32b355ed447f66 (diff) | |
| download | lwn-9059a3493efea6492451430c7e2fa0af799a2abb.tar.gz lwn-9059a3493efea6492451430c7e2fa0af799a2abb.zip | |
kconfig: fix relational operators for bool and tristate symbols
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 <nico@linaro.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/kbuild/kconfig-language.txt | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt index 262722d8867b..c4a293a03c33 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 |