(doc-group type
  «Dealing with types.»)

(defdoc (const? term)
  «Return `T` if the term refers to a constant, `NIL` otherwise.

   Constants cannot be modified with `set!`.  Trying to do so will result
   in an exception.»
  :doc-example
  «(const? 12345) ; a number
   ; ↳ T»
  :doc-example
  «(const? 'const?) ; a function
   ; ↳ NIL»
  :doc-example
  «(const? 'pi) ; a mathematical constant
   ; ↳ T»
  :doc-group type)

(defdoc (bignum? v)
  «Return `T` if the argument is a bignum, `NIL` otherwise.»
  :doc-group type
  :doc-group number
  :doc-see bignum)

(defdoc (int? v)
  «Return `T` if the argument is an integer, `NIL` otherwise.»
  :doc-group type
  :doc-group number
  :doc-see int-valued?)

(defdoc (str? v)
  «Return `T` if the argument is a string, `NIL` otherwise.»
  :doc-group type
  :doc-see str
  :doc-see str-utf8?)

(defdoc (gensym? v)
  «Return `T` if the argument is a gensym, `NIL` otherwise.»
  :doc-group type
  :doc-see sym?
  :doc-see sym)

(defdoc (ptr? v)
  «Return `T` if the argument is an abstract pointer, `NIL` otherwise.»
  :doc-group type
  :doc-group number
  :doc-see ptr)

(defdoc (table? v)
  «Return `T` if the argument is a table, `NIL` otherwise.»
  :doc-group type
  :doc-group table
  :doc-see table)

(defdoc (keyword? v)
  «Return `T` if the argument is a keyword, `NIL` otherwise.»
  :doc-group type)

(defdoc (type-of v)
  «Return the underlying type of the value.»
  :doc-example
  «(type-of 1)
   ; ↳ fixnum»
  :doc-example
  «(type-of NIL)
   ; ↳ null»
  :doc-example
  «(type-of T)
   ; ↳ bool»
  :doc-example
  «(type-of "hello")
   ; ↳ str»
  :doc-example
  «(type-of (arr 'u32 0 1 2))
   ; ↳ (arr u32)»
  :doc-group type
  :doc-see size-of)