[[b2.reference.modules.type]]
= type

Deals with target type declaration and defines target class which
supports typed targets.

1. [[b2.reference.modules.type.register]] `rule register ( type : suffixes * : base-type ? )`
+
Registers a target type, possible derived from a `base-type`. Providing
a list of suffixes here is a shortcut for separately calling the
link:#b2.reference.modules.type.register-suffixes[register-suffixes]
rule with the given suffixes and the
link:#b2.reference.modules.type.set-generated-target-suffix[set-generated-target-suffix]
rule with the first given suffix.

2. [[b2.reference.modules.type.register-suffixes]] `rule register-suffixes ( suffixes + : type )`
+
Specifies that files with suffix from `suffixes` be recognized as
targets of type `type`. Issues an error if a different type is already
specified for any of the suffixes.

3. [[b2.reference.modules.type.registered]] `rule registered ( type )`
+
Returns true iff type has been registered.

4. [[b2.reference.modules.type.validate]] `rule validate ( type )`
+
Issues an error if `type` is unknown.

5. [[b2.reference.modules.type.set-scanner]] `rule set-scanner ( type : scanner )`
+
Sets a scanner class that will be used for this type.

6. [[b2.reference.modules.type.get-scanner]] `rule get-scanner ( type : property-set )`
+
Returns a scanner instance appropriate to `type` and `property-set`.

7. [[b2.reference.modules.type.base]] `rule base ( type )`
+
Returns a base type for the given type or nothing in case the given type
is not derived.

8. [[b2.reference.modules.type.all-bases]] `rule all-bases ( type )`
+
Returns the given type and all of its base types in order of their
distance from type.

9. [[b2.reference.modules.type.all-derived]] `rule all-derived ( type )`
+
Returns the given type and all of its derived types in order of their
distance from type.

10. [[b2.reference.modules.type.is-derived]] `rule is-derived ( type base )`
+
Returns true if `type` is equal to `base` or has `base` as its direct or
indirect base.

11. [[b2.reference.modules.type.set-generated-target-suffix]] `rule set-generated-target-suffix ( type : properties * : suffix )`
+
Sets a file suffix to be used when generating a target of `type` with
the specified properties. Can be called with no properties if no suffix
has already been specified for the `type`. The `suffix` parameter can be
an empty string (`""`) to indicate that no suffix should be used.
+
Note that this does not cause files with `suffix` to be automatically
recognized as being of `type`. Two different types can use the same
suffix for their generated files but only one type can be auto-detected
for a file with that suffix. User should explicitly specify which one
using the
link:#b2.reference.modules.type.register-suffixes[register-suffixes]
rule.

12. [[b2.reference.modules.type.change-generated-target-suffix]] `rule change-generated-target-suffix ( type : properties * : suffix )`
+
Change the suffix previously registered for this type/properties
combination. If suffix is not yet specified, sets it.

13. [[b2.reference.modules.type.generated-target-suffix]] `rule generated-target-suffix ( type : property-set )`
+
Returns the suffix used when generating a file of `type` with the given
properties.

14. [[b2.reference.modules.type.set-generated-target-prefix]] `rule set-generated-target-prefix ( type : properties * : prefix )`
+
Sets a target prefix that should be used when generating targets of
`type` with the specified properties. Can be called with empty
properties if no prefix for `type` has been specified yet.
+
The `prefix` parameter can be empty string (`""`) to indicate that no
prefix should be used.
+
Usage example: library names use the `"lib"` prefix on unix.

15. [[b2.reference.modules.type.change-generated-target-prefix]] `rule change-generated-target-prefix ( type : properties * : prefix )`
+
Change the prefix previously registered for this type/properties
combination. If prefix is not yet specified, sets it.

16. [[b2.reference.modules.type.generated-target-prefix]] `rule generated-target-prefix ( type : property-set )`
+
Returns the prefix used when generating a file of `type` with the given
properties.

17. [[b2.reference.modules.type.type]] `rule type ( filename )`
+
Returns file type given its name. If there are several dots in filename,
tries each suffix. E.g. for name of "file.so.1.2" suffixes "2", "1", and
"so" will be tried.
