diff options
Diffstat (limited to 'libbuild2/rule.hxx')
| -rw-r--r-- | libbuild2/rule.hxx | 28 |
1 files changed, 12 insertions, 16 deletions
diff --git a/libbuild2/rule.hxx b/libbuild2/rule.hxx index 4b05379..af89124 100644 --- a/libbuild2/rule.hxx +++ b/libbuild2/rule.hxx @@ -24,13 +24,12 @@ namespace build2 // // Note: match() is only called once but may not be followed by apply(). // - // The match_extra argument is used to pass additional information that is - // only needed by some rule implementations. It is also a way for us to - // later pass more information without breaking source compatibility. + // The match_extra argument (the type is defined in target.hxx) is used to + // pass additional information that is only needed by some rule + // implementations. It is also a way for us to later pass more information + // without breaking source compatibility. // - struct match_extra - { - }; + struct match_extra; class LIBBUILD2_SYMEXPORT rule { @@ -172,18 +171,15 @@ namespace build2 public: // Some of the operations come in compensating pairs, such as update and // clean, install and uninstall. An ad hoc rule implementation may choose - // to provide a fallback implementation of a compensating operation if it - // is providing the other half (passed in the fallback argument). - // - // The default implementation calls rule::match() if fallback is absent - // and returns false if fallback is present. So an implementation that - // doesn't care about this semantics can implement the straight rule - // interface. + // to provide a fallback implementation of a reverse operation if it is + // providing the other half. // - virtual bool - match (action, target&, const string&, match_extra&, - optional<action> fallback) const; + virtual optional<action> + reverse_fallback (action, const target_type&) const; + // The default implementation forwards to the pattern's match() if there + // is a pattern and returns true otherwise. + // virtual bool match (action, target&, const string&, match_extra&) const override; |