Parse File at compile time, but not embedded

[Pie? via Digitalmars-d-learn]

On Monday, 6 June 2016 at 21:31:32 UTC, Alex Parrill wrote:
> On Monday, 6 June 2016 at 17:31:52 UTC, Pie? wrote:
>> Is it possible to parse a file at compile time without 
>> embedding it into the binary?
>>
>> I have a sort of "configuration" file that defines how to 
>> create some objects. I'd like to be able to read how to create 
>> them but not have that config file stick around in the binary.
>>
>> e.g., (simple contrived example follows)
>>
>> Config.txt
>>    x, my1
>>    y, my1
>>    z, my2
>>
>>
>> class my1 { }
>> class my2 { }
>>
>> void parseConfig(A)
>> {
>>     ....
>> }
>>
>> void main()
>> {
>>    parseConfig('Config.txt') // Effectively creates a mixin 
>> that mixes in auto x = new my1; auto y = new my1; auto z = new 
>> my2;
>> }
>>
>>
>> If parseConfig uses import('Config.txt') then config.txt will 
>> end up in the binary which I do not want. It would be easier 
>> to be able to use import and strip it out later if possible. 
>> Config.txt may contain secure information, which is why is 
>> doesn't belong in the binary.
>
> Most compilers, I believe, will not embed a string if it is not 
> used anywhere at runtime. DMD might not though, I'm not sure.

This doesn't seem to be the case. In a release build, even though 
I never "use" the string, it is embedded. I guess this is due to 
not using enum but enum seems to be much harder to work with if 
not impossible.


> But reading sensitive data at compile-time strikes me as 
> dangerous, depending on your use case. If you are reading 
> sensitive information at compile time, you are presumably going 
> to include that information in your binary (otherwise why would 
> you read it?), and your binary is not secure.

Not necessarily, You chased that rabbit quite far! The data your 
reading could contain sensitive information only used at compile 
time and not meant to embed. For example, the file could contain 
login and password to an SQL database that  you then connect, at 
compile time and retrieve that information the disregard the 
password(it is not needed at run time).