diff options
Diffstat (limited to 'build2/parser')
| -rw-r--r-- | build2/parser | 51 |
1 files changed, 36 insertions, 15 deletions
diff --git a/build2/parser b/build2/parser index 9b326b1..e1f6e77 100644 --- a/build2/parser +++ b/build2/parser @@ -110,8 +110,9 @@ namespace build2 value&& rhs, token_type kind); - // Return the value as well as the indication of whether this is a non- - // empty eval context (i.e., '()' potentially with whitespace in between). + // Return the value (can be NULL/typed) as well as the indication of + // whether this is a non-empty eval context (i.e., '()' potentially with + // whitespace in between). // pair<value, bool> parse_eval (token&, token_type&); @@ -187,26 +188,46 @@ namespace build2 return ns; } - // As above but return the result as a value (always untyped) indicating - // if it is NULL. The only way for the value to be NULL is if it is the - // result of a sole, unquoted variable expansion, function call, or - // context evaluation. + // As above but return the result as a value, which can be typed and NULL. // value - parse_names_value (token& t, token_type& tt, - const char* what = "name", - const string* separators = &name_separators) + parse_value (token& t, token_type& tt, + const char* what = "name", + const string* separators = &name_separators) { names ns; - return parse_names ( - t, tt, ns, false, what, separators, 0, nullptr, nullptr, nullptr) - ? value (move (ns)) - : value (nullptr); + pair<bool, const value_type*> p ( + parse_names ( + t, tt, ns, false, what, separators, 0, nullptr, nullptr, nullptr)); + + value r (p.second); // Potentially typed NULL value. + + // This should not fail since we are typing the result of reversal from + // the typed value. + // + if (p.first) // Not NULL. + r.assign (move (ns), nullptr); + + return r; } - // Append names and return true if the parsed value is NOT NULL. + // Append names and return the indication if the parsed value is NOT NULL + // (first) and whether it is typed (second). // - bool + // You may have noticed that what we return here is essentially a value + // and doing it this way (i.e., reversing it to untyped names and + // returning its type so that it can potentially be "typed back") is kind + // of backwards. The reason we are doing it this way is because in many + // places we expect things untyped and if we were to always return a + // (potentially typed) value, then we would have to reverse it in all + // those places. Still it may make sense to look into redesigning the + // whole thing one day. + // + // Currently the only way for the result to be NULL or have a type is if + // it is the result of a sole, unquoted variable expansion, function call, + // or context evaluation. + // + pair<bool, const value_type*> parse_names (token&, token_type&, names&, bool chunk = false, |