diff options
Diffstat (limited to 'build2/version/init.cxx')
| -rw-r--r-- | build2/version/init.cxx | 36 |
1 files changed, 29 insertions, 7 deletions
diff --git a/build2/version/init.cxx b/build2/version/init.cxx index c0ce4cd..69d7401 100644 --- a/build2/version/init.cxx +++ b/build2/version/init.cxx @@ -272,15 +272,37 @@ namespace build2 } } - // Enter variables. Note: some overridable, some not. + // Enter variables. // - auto& vp (var_pool.rw (rs)); + { + auto& vp (var_pool.rw (rs)); - // Alternative variable substitution symbols. - // - // @@ Note: should be moved to the 'in' module once we have it. - // - m.in_symbol = &vp.insert<string> ("in.symbol"); + // @@ Note: these should be moved to the 'in' module once we have it. + // + + // Alternative variable substitution symbol. + // + m.in_symbol = &vp.insert<string> ("in.symbol"); + + // Substitution mode. Valid values are 'strict' (default) and 'lax'. + // In the strict mode every substitution symbol is expected to start a + // substitution with the double symbol (e.g., $$) serving as an + // escape sequence. + // + // In the lax mode a pair of substitution symbols is only treated as a + // substitution if what's between them looks like a build2 variable + // name (i.e., doesn't contain spaces, etc). Everything else, + // including unterminated substitution symbols is copied as is. Note + // also that in this mode the double symbol is not treated as an + // escape sequence. + // + // The lax mode is mostly useful when trying to reuse existing .in + // files, for example from autoconf. Note, however, that the lax mode + // is still stricter than the autoconf's semantics which also leaves + // unknown substitutions as is. + // + m.in_substitution = &vp.insert<string> ("in.substitution"); + } // Register rules. // |