These access functions are implemented as macros and are put into <lexer.h> by the program headerer.pl
The macros access Int, Symbol, Float etc values of the current lexeme. However these are strored in a location which is named a bit different. For example the string of a symbol is stored in the string field of the lexeme. To be readable and to be compatible with future versions use these macros to access lexeme values when lexeme has any of these types.
#define lex_Int(x) lex_Long(x)
#define lex_Symbol(x) lex_String(x)
#define lex_Float(x) lex_Double(x)
#define lex_Char(x) lex_Long(x)
#define lex_Token(x) lex_Long(x)
#define lex_Code(x) lex_Long(x)