diff options
Diffstat (limited to 'src/libexpr/symbol-table.hh')
| -rw-r--r-- | src/libexpr/symbol-table.hh | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/src/libexpr/symbol-table.hh b/src/libexpr/symbol-table.hh index c97a0a2db..967a186dd 100644 --- a/src/libexpr/symbol-table.hh +++ b/src/libexpr/symbol-table.hh @@ -10,15 +10,11 @@ namespace nix { -/* Symbol table used by the parser and evaluator to represent and look - up identifiers and attributes efficiently. SymbolTable::create() - converts a string into a symbol. Symbols have the property that - they can be compared efficiently (using an equality test), - because the symbol table stores only one copy of each string. */ - -/* This class mainly exists to give us an operator<< for ostreams. We could also - return plain strings from SymbolTable, but then we'd have to wrap every - instance of a symbol that is fmt()ed, which is inconvenient and error-prone. */ +/** + * This class mainly exists to give us an operator<< for ostreams. We could also + * return plain strings from SymbolTable, but then we'd have to wrap every + * instance of a symbol that is fmt()ed, which is inconvenient and error-prone. + */ class SymbolStr { friend class SymbolTable; @@ -47,6 +43,11 @@ public: friend std::ostream & operator <<(std::ostream & os, const SymbolStr & symbol); }; +/** + * Symbols have the property that they can be compared efficiently + * (using an equality test), because the symbol table stores only one + * copy of each string. + */ class Symbol { friend class SymbolTable; @@ -66,6 +67,10 @@ public: bool operator!=(const Symbol other) const { return id != other.id; } }; +/** + * Symbol table used by the parser and evaluator to represent and look + * up identifiers and attributes efficiently. + */ class SymbolTable { private: @@ -74,6 +79,9 @@ private: public: + /** + * converts a string into a symbol. + */ Symbol create(std::string_view s) { // Most symbols are looked up more than once, so we trade off insertion performance |