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

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

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

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

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