proc countDefinedSymbols(symbols: StringTableRef): int {....raises: [], tags: [],
    forbids: [].}

proc defineSymbol(symbols: StringTableRef; symbol: string;
                  value: string = "true") {....raises: [], tags: [], forbids: [].}

proc initDefines(symbols: StringTableRef) {....raises: [], tags: [], forbids: [].}

proc undefSymbol(symbols: StringTableRef; symbol: string) {....raises: [],
    tags: [], forbids: [].}

iterator definedSymbolNames(symbols: StringTableRef): string {....raises: [],
    tags: [], forbids: [].}