The compiler directive ':- set_prolog_flag(double_quotes,Value)' is used to specify at compile time how the compiler shall deal with double quotes.

The predicate 'current_prolog_flag(?Flag,-Value)' can be used to query the value of a flag at execution time.

For Flag = double_quotes

     Value = chars      "hello" -> [h,e,l,l,o]
     Value = codes      "hello" -> [104,101,108,108,111]
     Value = atom       "hello" -> hello

By default, MINERVA reads a double quoted sequence of characters into a list of characters.

Suggested usage is to add a line to the start of a source file only when needed:

:- set_prolog_flag(double_quotes, codes).