Guess the data type that a string represents.
DataType_Type _slang_guess_type (String_Type s)
This function tries to determine whether its argument s represents
an integer or a floating point number. If it appears to be neither,
then a string is assumed. It returns one of three values depending on
the format of the string s:
Integer_Type : If it appears to be an integer
Double_Type : If it appears to be a double
String_Type : Anything else.
For example, _slang_guess_type("1e2") returns
Double_Type but _slang_guess_type("e12") returns
String_Type.
integer, string, double