Represents a configuration symbol:
(menu)config FOO
...
The following attributes are available. They should be viewed as read-only,
and some are implemented through @property magic (but are still efficient
to access due to internal caching).
Note: Prompts, help texts, and locations are stored in the Symbol's
MenuNode(s) rather than in the Symbol itself. Check the MenuNode class and
the Symbol.nodes attribute. This organization matches the C tools.
name:
The name of the symbol, e.g. "FOO" for 'config FOO'.
type:
The type of the symbol. One of BOOL, TRISTATE, STRING, INT, HEX, UNKNOWN.
UNKNOWN is for undefined symbols, (non-special) constant symbols, and
symbols defined without a type.
When running without modules (MODULES having the value n), TRISTATE
symbols magically change type to BOOL. This also happens for symbols
within choices in "y" mode. This matches the C tools, and makes sense for
menuconfig-like functionality.
orig_type:
The type as given in the Kconfig file, without any magic applied. Used
when printing the symbol.
str_value:
The value of the symbol as a string. Gives the value for string/int/hex
symbols. For bool/tristate symbols, gives "n", "m", or "y".
This is the symbol value that's used in relational expressions
(A = B, A != B, etc.)
Gotcha: For int/hex symbols, the exact format of the value must often be
preserved (e.g., when writing a .config file), hence why you can't get it
directly as an int. Do int(int_sym.str_value) or
int(hex_sym.str_value, 16) to get the integer value.
tri_value:
The tristate value of the symbol as an integer. One of 0, 1, 2,
representing n, m, y. Always 0 (n) for non-bool/tristate symbols.
This is the symbol value that's used outside of relation expressions
(A, !A, A && B, A || B).
assignable:
A tuple containing the tristate user values that can currently be
assigned to the symbol (that would be respected), ordered from lowest (0,
representing n) to highest (2, representing y). This corresponds to the
selections available in the menuconfig interface. The set of assignable
values is calculated from the symbol's visibility and selects/implies.
Returns the empty set for non-bool/tristate symbols and for symbols with
visibility n. The other possible values are (0, 2), (0, 1, 2), (1, 2),
(1,), and (2,). A (1,) or (2,) result means the symbol is visible but
"locked" to m or y through a select, perhaps in combination with the
visibility. menuconfig represents this as -M- and -*-, respectively.
For string/hex/int symbols, check if Symbol.visibility is non-0 (non-n)
instead to determine if the value can be changed.
Some handy 'assignable' idioms:
# Is 'sym' an assignable (visible) bool/tristate symbol?
if sym.assignable:
# What's the highest value it can be assigned? [-1] in Python
# gives the last element.
sym_high = sym.assignable[-1]
# The lowest?
sym_low = sym.assignable[0]
# Can the symbol be set to at least m?
if sym.assignable[-1] >= 1:
...
# Can the symbol be set to m?
if 1 in sym.assignable:
...
visibility:
The visibility of the symbol. One of 0, 1, 2, representing n, m, y. See
the module documentation for an overview of symbol values and visibility.
user_value:
The user value of the symbol. None if no user value has been assigned
(via Kconfig.load_config() or Symbol.set_value()).
Holds 0, 1, or 2 for bool/tristate symbols, and a string for the other
symbol types.
WARNING: Do not assign directly to this. It will break things. Use
Symbol.set_value().
config_string:
The .config assignment string that would get written out for the symbol
by Kconfig.write_config(). Returns the empty string if no .config
assignment would get written out.
In general, visible symbols, symbols with (active) defaults, and selected
symbols get written out. This includes all non-n-valued bool/tristate
symbols, and all visible string/int/hex symbols.
Symbols with the (no longer needed) 'option env=...' option generate no
configuration output, and neither does the special
'option defconfig_list' symbol.
Tip: This field is useful when generating custom configuration output,
even for non-.config-like formats. To write just the symbols that would
get written out to .config files, do this:
if sym.config_string:
*Write symbol, e.g. by looking sym.str_value*
This is a superset of the symbols written out by write_autoconf().
That function skips all n-valued symbols.
There usually won't be any great harm in just writing all symbols either,
though you might get some special symbols and possibly some "redundant"
n-valued symbol entries in there.
nodes:
A list of MenuNodes for this symbol. Will contain a single MenuNode for
most symbols. Undefined and constant symbols have an empty nodes list.
Symbols defined in multiple locations get one node for each location.
choice:
Holds the parent Choice for choice symbols, and None for non-choice
symbols. Doubles as a flag for whether a symbol is a choice symbol.
defaults:
List of (default, cond) tuples for the symbol's 'default' properties. For
example, 'default A && B if C || D' is represented as
((AND, A, B), (OR, C, D)). If no condition was given, 'cond' is
self.kconfig.y.
Note that 'depends on' and parent dependencies are propagated to
'default' conditions.
selects:
List of (symbol, cond) tuples for the symbol's 'select' properties. For
example, 'select A if B && C' is represented as (A, (AND, B, C)). If no
condition was given, 'cond' is self.kconfig.y.
Note that 'depends on' and parent dependencies are propagated to 'select'
conditions.
implies:
Like 'selects', for imply.
ranges:
List of (low, high, cond) tuples for the symbol's 'range' properties. For
example, 'range 1 2 if A' is represented as (1, 2, A). If there is no
condition, 'cond' is self.config.y.
Note that 'depends on' and parent dependencies are propagated to 'range'
conditions.
Gotcha: 1 and 2 above will be represented as (undefined) Symbols rather
than plain integers. Undefined symbols get their name as their string
value, so this works out. The C tools work the same way.
rev_dep:
Reverse dependency expression from other symbols selecting this symbol.
Multiple selections get ORed together. A condition on a select is ANDed
with the selecting symbol.
For example, if A has 'select FOO' and B has 'select FOO if C', then
FOO's rev_dep will be (OR, A, (AND, B, C)).
weak_rev_dep:
Like rev_dep, for imply.
direct_dep:
The 'depends on' dependencies. If a symbol is defined in multiple
locations, the dependencies at each location are ORed together.
Internally, this is used to implement 'imply', which only applies if the
implied symbol has expr_value(self.direct_dep) != 0. 'depends on' and
parent dependencies are automatically propagated to the conditions of
properties, so normally it's redundant to check the direct dependencies.
referenced:
A set() with all symbols and choices referenced in the properties and
property conditions of the symbol.
Also includes dependencies inherited from surrounding menus and if's.
Choices appear in the dependencies of choice symbols.
env_var:
If the Symbol has an 'option env="FOO"' option, this contains the name
("FOO") of the environment variable. None for symbols without no
'option env'.
'option env="FOO"' acts like a 'default' property whose value is the
value of $FOO.
Symbols with 'option env' are never written out to .config files, even if
they are visible. env_var corresponds to a flag called SYMBOL_AUTO in the
C implementation.
is_allnoconfig_y:
True if the symbol has 'option allnoconfig_y' set on it. This has no
effect internally (except when printing symbols), but can be checked by
scripts.
is_constant:
True if the symbol is a constant (quoted) symbol.
kconfig:
The Kconfig instance this symbol is from.
