The semicolon is Lisp syntax for comments. T is the way you write true in Lisp. Most-negative-fixnum is the most negative number Lisp can represent without prom

The semicolon is Lisp syntax for comments. T is the way you write true in Lisp. Most-negative-fixnum is the most negative number Lisp can represent without promotion to bignum (so it can be int_min if int is roughly equivalent to size_t).