Put RDoc comments into array.c, and refine rdoc/ri to deal with stuff that arose

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@5202 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 888 insertions, 0 deletions

diff --git a/array.c b/array.c
index 5f41d26409..8daa6accf0 100644
--- a/array.c
+++ b/array.c
@@ -214,6 +214,44 @@ rb_check_array_type(ary)
 
 static VALUE rb_ary_replace _((VALUE, VALUE));
 
+/* 
+ * call-seq:
+ *       Array.new(size=0, obj=nil)
+ *       Array.new(array)
+ *       Array.new(size) {|i| ...}
+
+ * Returns a new array. In the first form, the new array is
+ * empty. In the second it is created with _size_ copies of _obj_
+ * (that is, _size_ references to the same
+ * _obj_). The third form creates a copy of the array
+ * passed as a parameter (the array is generated by calling
+ * to_ary  on the parameter). In the last form, an array
+ * of the given size is created. Each element in this array is
+ * calculated by passing the element's index to the given block and
+ * storing the return value.
+ *
+ *   Array.new
+ *   Array.new(2)
+ *   Array.new(5, "A")
+ * 
+ *   # only one copy of the object is created
+ *   a = Array.new(2, Hash.new)
+ *   a[0]['cat'] = 'feline'
+ *   a
+ *   a[1]['cat'] = 'Felix'
+ *   a
+ * 
+ *   # here multiple copies are created
+ *   a = Array.new(2) { Hash.new }
+ *   a[0]['cat'] = 'feline'
+ *   a
+ * 
+ *   squares = Array.new(5) {|i| i*i}
+ *   squares
+ * 
+ *   copy = Array.new(squares)
+ */
+
 static VALUE
 rb_ary_initialize(argc, argv, ary)
     int argc;
@@ -270,6 +308,15 @@ rb_ary_initialize(argc, argv, ary)
     return ary;
 }
 
+
+/* 
+* Returns a new array populated with the given objects. 
+*
+*   Array.[]( 1, 'a', /^A/ )
+*   Array[ 1, 'a', /^A/ ]
+*   [ 1, 'a', /^A/ ]
+*/
+
 static VALUE
 rb_ary_s_create(argc, argv, klass)
     int argc;
@@ -329,6 +376,19 @@ rb_ary_store(ary, idx, val)
     RARRAY(ary)->ptr[idx] = val;
 }
 
+/* 
+ * call-seq:
+ *   array << obj            => array
+ *  
+ *   Append---Pushes the given object on to the end of this array. This
+ *   expression returns the array itself, so several appends
+ *   may be chained together.
+ *
+ *     [ 1, 2 ] << "c" << "d" << [ 3, 4 ]
+ *             #=>  [ 1, 2, "c", "d", [ 3, 4 ] ]
+ *
+ */
+
 VALUE
 rb_ary_push(ary, item)
     VALUE ary;
@@ -338,6 +398,19 @@ rb_ary_push(ary, item)
     return ary;
 }
 
+/* 
+ * call-seq:
+ *   array.push(obj, ... )   => array
+ *  
+ *   Append---Pushes the given object(s) on to the end of this array. This
+ *   expression returns the array itself, so several appends
+ *   may be chained together.
+ *
+ *     a = [ "a", "b", "c" ]
+ *     a.push("d", "e", "f")  
+ *             #=> ["a", "b", "c", "d", "e", "f"]
+ */
+
 static VALUE
 rb_ary_push_m(argc, argv, ary)
     int argc;
@@ -350,6 +423,18 @@ rb_ary_push_m(argc, argv, ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.pop  => obj or nil
+ *  
+ *  Removes the last element from <i>self</i> and returns it, or
+ *  <code>nil</code> if the array is empty.
+ *     
+ *     a = [ "a", "m", "z" ]
+ *     a.pop   #=> "z"
+ *     a       #=> ["a", "m"]
+ */
+
 VALUE
 rb_ary_pop(ary)
     VALUE ary;
@@ -381,6 +466,19 @@ ary_make_shared(ary)
     }
 }
 
+/*
+ *  call-seq:
+ *     array.shift   =>   obj or nil
+ *  
+ *  Returns the first element of <i>self</i> and removes it (shifting all
+ *  other elements down by one). Returns <code>nil</code> if the array
+ *  is empty.
+ *     
+ *     args = [ "-m", "-q", "filename" ]
+ *     args.shift   #=> "-m"
+ *     args         #=> ["-q", "filename"]
+ */
+
 VALUE
 rb_ary_shift(ary)
     VALUE ary;
@@ -420,6 +518,18 @@ rb_ary_unshift(ary, item)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.unshift(obj, ...)  => array
+ *  
+ *  Prepends objects to the front of <i>array</i>.
+ *  other elements up one.
+ *     
+ *     a = [ "b", "c", "d" ]
+ *     a.unshift("a")   #=> ["a", "b", "c", "d"]
+ *     a.unshift(1, 2)  #=> [ 1, 2, "a", "b", "c", "d"]
+ */
+
 static VALUE
 rb_ary_unshift_m(argc, argv, ary)
     int argc;
@@ -488,6 +598,40 @@ rb_ary_subseq(ary, beg, len)
     return ary2;
 }
 
+/* 
+ * call-seq:
+ *       array[int]                  => obj      or nil
+ *       array[start, length]        => an_array or nil
+ *       array[range]                => an_array or nil
+ *       array.slice(int)            => obj      or nil
+ *       array.slice(start, length)  => an_array or nil
+ *       array.slice(range)          => an_array or nil
+ *
+ * Element Reference---Returns the element at index _int_,
+ * or returns a subarray starting at index _start_ and
+ * continuing for _length_ elements, or returns a subarray
+ * specified by _range_.
+ * Negative indices count backward from the end of the
+ * array (-1 is the last element). Returns nil if any indices
+ * are out of range unless the index equals the array size and a
+ * _length_ or _range_ parameter is given, in which case an
+ * empty array is returned.
+ *
+ *     a = [ "a", "b", "c", "d", "e" ]
+ *     a[2] +  a[0] + a[1]    #=> "cab"
+ *     a[6]                   #=> nil
+ *     a[1, 2]                #=> [ "b", "c" ]
+ *     a[1..3]                #=> [ "b", "c", "d" ]
+ *     a[4..7]                #=> [ "e" ]
+ *     a[6..10]               #=> nil
+ *     a[-3, 3]               #=> [ "c", "d", "e" ]
+ *     # special cases
+ *     a[5]                   #=> nil
+ *     a[5, 1]                #=> []
+ *     a[5..10]               #=> []
+ *
+ */
+
 VALUE
 rb_ary_aref(argc, argv, ary)
     int argc;
@@ -531,6 +675,21 @@ rb_ary_aref(argc, argv, ary)
     return rb_ary_entry(ary, NUM2LONG(arg));
 }
 
+/* 
+ * call-seq:
+ *      array.at(int)   #=>   obj  or nil
+ *
+ *   Returns the element at index int. A
+ *   negative index counts from the end of _self_.  Returns +nil+
+ *   if the index is out of range. See also Array.[].
+ *   (Array.at is slightly faster than Array.[], as it
+ *   does not accept ranges and so on.)
+ *
+ *     a = [ "a", "b", "c", "d", "e" ]
+ *     a.at(0)     #=> "a"
+ *     a.at(-1)    #=> "e"
+ */
+
 static VALUE
 rb_ary_at(ary, pos)
     VALUE ary, pos;
@@ -538,6 +697,17 @@ rb_ary_at(ary, pos)
     return rb_ary_entry(ary, NUM2LONG(pos));
 }
 
+/*
+ *  call-seq:
+ *     array.first   =>   obj or nil
+ *  
+ *  Returns the first element of the array. If the array is empty,
+ *  returns <code>nil</code>.
+ *     
+ *     a = [ "q", "r", "s", "t" ]
+ *     a.first   #=> "q"
+ */
+
 static VALUE
 rb_ary_first(argc, argv, ary)
     int argc;
@@ -563,6 +733,17 @@ rb_ary_first(argc, argv, ary)
     }
 }
 
+/*
+ *  call-seq:
+ *     array.last     =>  obj or nil
+ *     array.last(n)  =>  an_array
+ *  
+ *  Returns the last element(s) of <i>self</i>. If the array is empty,
+ *  the first form returns <code>nil</code>.
+ *     
+ *     [ "w", "x", "y", "z" ].last   #=> "z"
+ */
+
 static VALUE
 rb_ary_last(argc, argv, ary)
     int argc;
@@ -588,6 +769,26 @@ rb_ary_last(argc, argv, ary)
     }
 }
 
+/*
+ *  call-seq:
+ *     array.fetch(index)                => obj
+ *     array.fetch(index, default )      => obj
+ *     array.fetch(index) {|i| block }   => obj
+ *  
+ *  Tries to return the element at position <i>index</i>. If the index
+ *  lies outside the array, the first form throws an
+ *  <code>IndexError</code> exception, the second form returns
+ *  <i>default</i>, and the third form returns the value of invoking
+ *  the block, passing in the index. Negative values of <i>idex</i>
+ *  count from the end of the array.
+ *     
+ *     a = [ 11, 22, 33, 44 ]
+ *     a.fetch(1)               #=> 22
+ *     a.fetch(-1)              #=> 44
+ *     a.fetch(4, 'cat')        #=> "cat"
+ *     a.fetch(4) { |i| i*i }   #=> 16
+ */
+
 static VALUE
 rb_ary_fetch(argc, argv, ary)
     int argc;
@@ -618,6 +819,19 @@ rb_ary_fetch(argc, argv, ary)
     return RARRAY(ary)->ptr[idx];
 }
 
+/*
+ *  call-seq:
+ *     array.index(obj)   =>  int or nil
+ *  
+ *  Returns the index of the first object in <i>self</i> such that is 
+ *  <code>==</code> to <i>obj</i>. Returns <code>nil</code> if
+ *  no match is found.
+ *     
+ *     a = [ "a", "b", "c" ]
+ *     a.index("b")   #=> 1
+ *     a.index("z")   #=> nil
+ */
+
 static VALUE
 rb_ary_index(ary, val)
     VALUE ary;
@@ -632,6 +846,19 @@ rb_ary_index(ary, val)
     return Qnil;
 }
 
+/*
+ *  call-seq:
+ *     array.rindex(obj)    =>  int or nil
+ *  
+ *  Returns the index of the last object in <i>arr</i> 
+ *  <code>==</code> to <i>obj</i>. Returns <code>nil</code> if
+ *  no match is found.
+ *     
+ *     a = [ "a", "b", "b", "b", "c" ]
+ *     a.rindex("b")   #=> 3
+ *     a.rindex("z")   #=> nil
+ */
+
 static VALUE
 rb_ary_rindex(ary, val)
     VALUE ary;
@@ -646,6 +873,14 @@ rb_ary_rindex(ary, val)
     return Qnil;
 }
 
+/*
+ *  call-seq:
+ *     array.indexes( i1, i2, ... iN )   => an_array
+ *     array.indices( i1, i2, ... iN )   => an_array
+ *  
+ *  Deprecated; use <code>Array#select</code>.
+ */
+
 static VALUE
 rb_ary_indexes(argc, argv, ary)
     int argc;
@@ -742,6 +977,34 @@ rb_ary_update(ary, beg, len, rpl)
     }
 }
 
+/* 
+ * call-seq:
+ *    array[int] = obj                  =>  obj
+ *    array[start, length] = an_array   =>  an_array
+ *    array[range] = an_array           =>  an_array
+ *
+ *   Element Assignment---Sets the element at index _int_,
+ *   or replaces a subarray starting at index _start_ and
+ *   continuing for _length_ elements, or replaces a subarray
+ *   specified by _range_.  If _int_ is greater than
+ *   the current capacity of the array, the array grows
+ *   automatically. A negative _int_ will count backward
+ *   from the end of the array. Inserts elements if _length_ is
+ *   zero. If _an_array is +nil+, deletes elements from _self_.
+ *   An +IndexError+ is raised if a
+ *   negative index points past the beginning of the array. See also
+ *   Array.push, and Array.unshift.
+ * 
+ *     a = Array.new
+ *     a[4] = "4";                
+ *     a[0, 3] = [ 'a', 'b', 'c' ]
+ *     a[1..2] = [ 1, 2 ];        
+ *     a[0, 2] = "?";             
+ *     a[0..2] = "A";             
+ *     a[-1]   = "Z";              
+ *     a[1..-1] = nil;             
+ */
+
 static VALUE
 rb_ary_aset(argc, argv, ary)
     int argc;
@@ -782,6 +1045,18 @@ fixnum:
     return argv[1];
 }
 
+/*
+ *  call-seq:
+ *     array.insert(index, obj...)  => array
+ *  
+ *  Inserts the given values before the element with the given index
+ *  (which may be negative).
+ *     
+ *     a = %w{ a b c d }
+ *     a.insert(2, 99)         #=> ["a", "b", 99, "c", "d"]
+ *     a.insert(-2, 1, 2, 3)   #=> ["a", "b", 99, "c", 1, 2, 3, "d"]
+ */
+
 static VALUE
 rb_ary_insert(argc, argv, ary)
     int argc;
@@ -806,6 +1081,21 @@ rb_ary_insert(argc, argv, ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.each {|item| block }   =>   array
+ *  
+ *  Calls <i>block</i> once for each element in <i>self</i>, passing that
+ *  element as a parameter.
+ *     
+ *     a = [ "a", "b", "c" ]
+ *     a.each {|x| print x, " -- " }
+ *     
+ *  produces:
+ *     
+ *     a -- b -- c --
+ */
+
 VALUE
 rb_ary_each(ary)
     VALUE ary;
@@ -818,6 +1108,21 @@ rb_ary_each(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.each_index {|index| block }  =>  array
+ *  
+ *  Same as <code>Array#each</code>, but passes the index of the element
+ *  instead of the element itself.
+ *     
+ *     a = [ "a", "b", "c" ]
+ *     a.each_index {|x| print x, " -- " }
+ *     
+ *  produces:
+ *     
+ *     0 -- 1 -- 2 --
+ */
+
 static VALUE
 rb_ary_each_index(ary)
     VALUE ary;
@@ -830,6 +1135,21 @@ rb_ary_each_index(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.reverse_each {|item| block } 
+ *  
+ *  Same as <code>Array#each</code>, but traverses <i>self</i> in reverse
+ *  order.
+ *     
+ *     a = [ "a", "b", "c" ]
+ *     a.reverse_each {|x| print x, " " }
+ *     
+ *  produces:
+ *     
+ *     c b a
+ */
+
 static VALUE
 rb_ary_reverse_each(ary)
     VALUE ary;
@@ -845,6 +1165,15 @@ rb_ary_reverse_each(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.length -> int
+ *  
+ *  Returns the number of elements in <i>self</i>. May be zero.
+ *     
+ *     [ 1, 2, 3, 4, 5 ].length   #=> 5
+ */
+
 static VALUE
 rb_ary_length(ary)
     VALUE ary;
@@ -852,6 +1181,15 @@ rb_ary_length(ary)
     return LONG2NUM(RARRAY(ary)->len);
 }
 
+/*
+ *  call-seq:
+ *     array.empty?   => true or false
+ *  
+ *  Returns <code>true</code> if <i>self</i> array contains no elements.
+ *     
+ *     [].empty?   #=> true
+ */
+
 static VALUE
 rb_ary_empty_p(ary)
     VALUE ary;
@@ -933,6 +1271,17 @@ rb_ary_join(ary, sep)
     return result;
 }
 
+/*
+ *  call-seq:
+ *     array.join(sep=$,)    => str
+ *  
+ *  Returns a string created by converting each element of the array to
+ *  a string, separated by <i>sep</i>.
+ *     
+ *     [ "a", "b", "c" ].join        #=> "abc"
+ *     [ "a", "b", "c" ].join("-")   #=> "a-b-c"
+ */
+
 static VALUE
 rb_ary_join_m(argc, argv, ary)
     int argc;
@@ -947,6 +1296,16 @@ rb_ary_join_m(argc, argv, ary)
     return rb_ary_join(ary, sep);
 }
 
+/*
+ *  call-seq:
+ *     array.to_s -> string
+ *  
+ *  Returns _self_<code>.join</code>.
+ *     
+ *     [ "a", "e", "i", "o" ].to_s   #=> "aeio"
+ *
+ */
+
 VALUE
 rb_ary_to_s(ary)
     VALUE ary;
@@ -1067,6 +1426,14 @@ rb_ary_inspect(ary)
     return rb_protect_inspect(inspect_ary, ary, 0);
 }
 
+/*
+ *  call-seq:
+ *     array.to_a -> array
+ *  
+ *  Returns _self_. If called on a subclass of Array, converts
+ *  the receiver to an Array object.
+ */
+
 static VALUE
 rb_ary_to_a(ary)
     VALUE ary;
@@ -1079,6 +1446,13 @@ rb_ary_to_a(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.to_ary -> array
+ *  
+ *  Returns _self_.
+ */
+
 static VALUE
 rb_ary_to_ary_m(ary)
     VALUE ary;
@@ -1107,6 +1481,17 @@ rb_ary_reverse(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.reverse!   => array 
+ *  
+ *  Reverses _self_ in place.
+ *     
+ *     a = [ "a", "b", "c" ]
+ *     a.reverse!       #=> ["c", "b", "a"]
+ *     a                #=> ["c", "b", "a"]
+ */
+
 static VALUE
 rb_ary_reverse_bang(ary)
     VALUE ary;
@@ -1114,6 +1499,16 @@ rb_ary_reverse_bang(ary)
     return rb_ary_reverse(ary);
 }
 
+/*
+ *  call-seq:
+ *     array.reverse -> an_array
+ *  
+ *  Returns a new array containing <i>self</i>'s elements in reverse order.
+ *     
+ *     [ "a", "b", "c" ].reverse   #=> ["c", "b", "a"]
+ *     [ 1 ].reverse               #=> [1]
+ */
+
 static VALUE
 rb_ary_reverse_m(ary)
     VALUE ary;
@@ -1167,6 +1562,22 @@ sort_unlock(ary)
 }
 
 VALUE
+/*
+ *  call-seq:
+ *     array.sort!                   => array
+ *     array.sort! {| a,b | block }  => array 
+ *  
+ *  Sorts _self_. Comparisons for
+ *  the sort will be done using the <code><=></code> operator or using
+ *  an optional code block. The block implements a comparison between
+ *  <i>a</i> and <i>b</i>, returning -1, 0, or +1. See also
+ *  <code>Enumerable#sort_by</code>.
+ *     
+ *     a = [ "d", "a", "e", "c", "b" ]
+ *     a.sort                    #=> ["a", "b", "c", "d", "e"]
+ *     a.sort {|x,y| y <=> x }   #=> ["e", "d", "c", "b", "a"]
+ */
+
 rb_ary_sort_bang(ary)
     VALUE ary;
 {
@@ -1178,6 +1589,22 @@ rb_ary_sort_bang(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.sort                   => an_array 
+ *     array.sort {| a,b | block }  => an_array 
+ *  
+ *  Returns a new array created by sorting <i>self</i>. Comparisons for
+ *  the sort will be done using the <code><=></code> operator or using
+ *  an optional code block. The block implements a comparison between
+ *  <i>a</i> and <i>b</i>, returning -1, 0, or +1. See also
+ *  <code>Enumerable#sort_by</code>.
+ *     
+ *     a = [ "d", "a", "e", "c", "b" ]
+ *     a.sort                    #=> ["a", "b", "c", "d", "e"]
+ *     a.sort {|x,y| y <=> x }   #=> ["e", "d", "c", "b", "a"]
+ */
+
 VALUE
 rb_ary_sort(ary)
     VALUE ary;
@@ -1187,6 +1614,20 @@ rb_ary_sort(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.collect {|obj| block }  -> an_array
+ *     array.map     {|obj| block }  -> an_array
+ *  
+ *  Invokes <i>block</i> once for each element of <i>self</i>. Creates a 
+ *  new array containing the values returned by the block.
+ *  See also Enumerable#collect</code>.
+ *     
+ *     a = [ "a", "b", "c", "d" ]
+ *     a.collect {|x| x + "!" }   #=> ["a!", "b!", "c!", "d!"]
+ *     a                          #=> ["a", "b", "c", "d"]
+ */
+
 static VALUE
 rb_ary_collect(ary)
     VALUE ary;
@@ -1205,6 +1646,20 @@ rb_ary_collect(ary)
     return collect;
 }
 
+/* 
+ * call-seq:
+ *    array.collect! {|obj} ...}   =>   array
+ *    array.map!     {|obj} ...}   =>   array
+ *
+ *   Invokes the block once for each element of _self_self, replacing the
+ *   element with the value returned by _block_.
+ *   See also Enumerable.collect.
+ *   
+ *     a = [ "a", "b", "c", "d" ]
+ *     a.collect! {|x| x + "!" }
+ *     a             #=>  [ "a!", "b!", "c!", "d!" ]
+ */
+
 static VALUE
 rb_ary_collect_bang(ary)
     VALUE ary;
@@ -1251,6 +1706,21 @@ rb_values_at(obj, olen, argc, argv, func)
     return result;
 }
 
+/* 
+ * call-seq:
+ *   array.values_at(selector,... )  => an_array
+ *   Returns an array containing the elements in
+ *   _self_ corresponding to the given selector(s). The selectors
+ *   may be either integer indices or ranges. 
+ *   See also </code>.select<code>.
+ * 
+ *      a = %w{ a b c d e f }
+ *      a.values_at(1, 3, 5)
+ *      a.values_at(1, 3, 5, 7)
+ *      a.values_at(-1, -3, -5, -7)
+ *      a.values_at(1..3, 2...5)
+ */
+
 static VALUE
 rb_ary_values_at(argc, argv, ary)
     int argc;
@@ -1260,6 +1730,21 @@ rb_ary_values_at(argc, argv, ary)
     return rb_values_at(ary, RARRAY(ary)->len, argc, argv, rb_ary_entry);
 }
 
+/*
+ *  call-seq:
+ *     array.select {|i| block } -> an_array
+ *  
+ *  Invokes the block passing in successive elements from <i>arr</i>,
+ *  returning an array containing those elements for which the block
+ *  returns a true value (equivalent to <code>Enumerable#select</code>).
+ *     
+ *     a = %w{ a b c d e f }
+ *     a.select(1, 3, 5)               #=> ["b", "d", "f"]
+ *     a.select(1, 3, 5, 7)            #=> ["b", "d", "f", nil]
+ *     a.select(-1, -3, -5, -7)        #=> ["f", "d", "b", nil]
+ *     a.select {|v| v =~ /[aeiou]/}   #=> ["a", "e"]
+ */
+
 static VALUE
 rb_ary_select(argc, argv, ary)
     int argc;
@@ -1281,6 +1766,23 @@ rb_ary_select(argc, argv, ary)
     return result;
 }
 
+/*
+ *  call-seq:
+ *     array.delete(obj)               => obj or nil 
+ *     array.delete(obj) {| | block }  => obj or nil
+ *  
+ *  Deletes items from <i>self</i> that are equal to <i>obj</i>. If
+ *  the item is not found, returns <code>nil</code>. If the optional
+ *  code block is given, returns the result of <i>block</i> if the item
+ *  is not found.
+ *     
+ *     a = [ "a", "b", "b", "b", "c" ]
+ *     a.delete("b")                   #=> "b"
+ *     a                               #=> ["a", "c"]
+ *     a.delete("z")                   #=> nil
+ *     a.delete("z") { "not found" }   #=> "not found"
+ */
+
 VALUE
 rb_ary_delete(ary, item)
     VALUE ary;
@@ -1337,6 +1839,20 @@ rb_ary_delete_at(ary, pos)
     return del;
 }
 
+/*
+ *  call-seq:
+ *     array.delete_at(index)  -> obj or nil
+ *  
+ *  Deletes the element at the specified index, returning that element,
+ *  or <code>nil</code> if the index is out of range. See also
+ *  <code>Array#slice!</code>.
+ *     
+ *     a = %w( ant bat cat dog )
+ *     a.delete_at(2)    #=> "cat"
+ *     a                 #=> ["ant", "bat", "dog"]
+ *     a.delete_at(99)   #=> nil
+ */
+
 static VALUE
 rb_ary_delete_at_m(ary, pos)
     VALUE ary, pos;
@@ -1344,6 +1860,31 @@ rb_ary_delete_at_m(ary, pos)
     return rb_ary_delete_at(ary, NUM2LONG(pos));
 }
 
+/*
+ *  call-seq:
+ *     array.slice!(int)           => obj or nil
+ *     array.slice!(start, length) => sub_array or nil
+ *     array.slice!(range)         => sub_array or nil 
+ *  
+ *  Deletes the element(s) given by an index (optionally with a length)
+ *  or by a range. Returns the deleted object, subarray, or
+ *  <code>nil</code> if the index is out of range. Equivalent to:
+ *     
+ *     def slice!(*args)
+ *       result = self[*args]
+ *       self[*args] = nil
+ *       result
+ *     end
+ *     
+ *     a = [ "a", "b", "c" ]
+ *     a.slice!(1)     #=> "b"
+ *     a               #=> ["a", "c"]
+ *     a.slice!(-1)    #=> "c"
+ *     a               #=> ["a"]
+ *     a.slice!(100)   #=> nil
+ *     a               #=> ["a"]
+ */
+
 static VALUE
 rb_ary_slice_bang(argc, argv, ary)
     int argc;
@@ -1373,6 +1914,16 @@ rb_ary_slice_bang(argc, argv, ary)
     return rb_ary_delete_at(ary, NUM2LONG(arg1));
 }
 
+/*
+ *  call-seq:
+ *     array.reject! {| | block }  -> array or nil
+ *  
+ *  Equivalent to <code>Array#delete_if</code>, deleting elements from
+ *  _self_ for which the block evaluates to true, but returns
+ *  <code>nil</code> if no changes were made. Also see
+ *  <code>Enumerable#reject</code>.
+ */
+
 static VALUE
 rb_ary_reject_bang(ary)
     VALUE ary;
@@ -1393,6 +1944,14 @@ rb_ary_reject_bang(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     arr.reject {|item| block }  -> an_array
+ *  
+ *  Returns a new array containing the items in _self_
+ *  for which the block is not true.
+ */
+
 static VALUE
 rb_ary_reject(ary)
     VALUE ary;
@@ -1402,6 +1961,17 @@ rb_ary_reject(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.delete_if {|item| block }  -> array
+ *  
+ *  Deletes every element of <i>self</i> for which <i>block</i> evaluates
+ *  to <code>true</code>.
+ *     
+ *     a = [ "a", "b", "c" ]
+ *     a.delete_if {|x| x >= "b" }   #=> ["a"]
+ */
+
 static VALUE
 rb_ary_delete_if(ary)
     VALUE ary;
@@ -1410,6 +1980,28 @@ rb_ary_delete_if(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.zip(arg, ...)                   -> an_array
+ *     array.zip(arg, ...) {| arr | block }  -> nil
+ *  
+ *  Converts any arguments to arrays, then merges elements of
+ *  <i>self</i> with corresponding elements from each argument. This
+ *  generates a sequence of <code>self#size</code> <em>n</em>-element
+ *  arrays, where <em>n</em> is one more that the count of arguments. If
+ *  the size of any arguemnt is less than <code>enumObj#size</code>,
+ *  <code>nil</code> values are supplied. If a block given, it is
+ *  invoked for each output array, otherwise an array of arrays is
+ *  returned.
+ *     
+ *     a = [ 4, 5, 6 ]
+ *     b = [ 7, 8, 9 ]
+ *     
+ *     [1,2,3].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
+ *     [1,2].zip(a,b)         #=> [[1, 4, 7], [2, 5, 8]]
+ *     a.zip([1,2],[8])       #=> [[4,1,8], [5,2,nil], [6,nil,nil]]
+ */
+
 static VALUE
 rb_ary_zip(argc, argv, ary)
     int argc;
@@ -1449,6 +2041,17 @@ rb_ary_zip(argc, argv, ary)
     return result;
 }
 
+/*
+ *  call-seq:
+ *     array.transpose -> an_array
+ *  
+ *  Assumes that <i>self</i> is an array of arrays and transposes the
+ *  rows and columns.
+ *     
+ *     a = [[1,2], [3,4], [5,6]]
+ *     a.transpose   #=> [[1, 3, 5], [2, 4, 6]]
+ */
+
 static VALUE
 rb_ary_transpose(ary)
     VALUE ary;
@@ -1478,6 +2081,18 @@ rb_ary_transpose(ary)
     return result;
 }
 
+/*
+ *  call-seq:
+ *     array.replace(other_array)  => array
+ *  
+ *  Replaces the contents of <i>self</i> with the contents of
+ *  <i>other_array</i>, truncating or expanding if necessary.
+ *     
+ *     a = [ "a", "b", "c", "d", "e" ]
+ *     a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
+ *     a                              #=> ["x", "y", "z"]
+ */
+
 static VALUE
 rb_ary_replace(copy, orig)
     VALUE copy, orig;
@@ -1496,6 +2111,15 @@ rb_ary_replace(copy, orig)
     return copy;
 }
 
+/* 
+ * call-seq:
+ *     array.clear    =>  array
+ *   Removes all elements from _self_.
+ *
+ *     a = [ "a", "b", "c", "d", "e" ]
+ *     a.clear    #=> [ ]
+ */
+
 VALUE
 rb_ary_clear(ary)
     VALUE ary;
@@ -1509,6 +2133,30 @@ rb_ary_clear(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.fill(obj) -> array
+ *     array.fill(obj, start [, length])          => array
+ *     array.fill(obj, range )                    => array
+ *     array.fill {|i| block }                    => array
+ *     array.fill(start [, length] ) {|i| block } => array
+ *     array.fill(range) {|i| block }             => array
+ *  
+ *  The first three forms set the selected elements of <i>self</i> (which
+ *  may be the entire array) to <i>obj</i>. A <i>start</i> of
+ *  <code>nil</code> is equivalent to zero. A <i>length</i> of
+ *  <code>nil</code> is equivalent to <i>arr</i>.length. The last three
+ *  forms fill the array with the value of the block. The block is
+ *  passed the absolute index of each element to be filled.
+ *     
+ *     a = [ "a", "b", "c", "d" ]
+ *     a.fill("x")              #=> ["x", "x", "x", "x"]
+ *     a.fill("z", 2, 2)        #=> ["x", "x", "z", "z"]
+ *     a.fill("y", 0..1)        #=> ["y", "y", "z", "z"]
+ *     a.fill {|i| i*i}         #=> [0, 1, 4, 9]
+ *     a.fill(-2) {|i| i*i*i}   #=> [0, 1, 8, 27]
+ */
+
 static VALUE
 rb_ary_fill(argc, argv, ary)
     int argc;
@@ -1580,6 +2228,16 @@ rb_ary_fill(argc, argv, ary)
     return ary;
 }
 
+/* 
+ * call-seq:
+ *    array + other_array   => an_array
+ *
+ *   Concatenation---Returns a new array built by concatenating the
+ *   two arrays together to produce a third array.
+ * 
+ *     [ 1, 2, 3 ] + [ 4, 5 ]    #=> [ 1, 2, 3, 4, 5 ]
+ */
+
 VALUE
 rb_ary_plus(x, y)
     VALUE x, y;
@@ -1596,6 +2254,15 @@ rb_ary_plus(x, y)
     return z;
 }
 
+/* 
+ * self.concat(other_array)   =>  array
+ *
+ *  Appends the elements in other_array to _self_.
+ *  
+ *     [ "a", "b" ].concat( ["c", "d"] ) #=> [ "a", "b", "c", "d" ]
+ */
+
+
 VALUE
 rb_ary_concat(x, y)
     VALUE x, y;
@@ -1607,6 +2274,21 @@ rb_ary_concat(x, y)
     return x;
 }
 
+
+/* 
+ * call-seq:
+ *     array * int     =>    an_array
+ *     array * str     =>    a_string
+ *
+ *   Repetition---With a String argument, equivalent to
+ *   self.join(str). Otherwise, returns a new array
+ *   built by concatenating the _int_ copies of _self_.
+ *
+ *
+ *     [ 1, 2, 3 ] * 3    #=> [ 1, 2, 3, 1, 2, 3, 1, 2, 3 ]
+ *
+ */
+
 static VALUE
 rb_ary_times(ary, times)
     VALUE ary, times;
@@ -1640,6 +2322,26 @@ rb_ary_times(ary, times)
     return ary2;
 }
 
+/* 
+ *   call-seq:
+ *     array.assoc(obj)   =>  an_array  or  nil
+ *
+ *   Searches through an array whose elements are also arrays
+ *   comparing _obj_ with the first element of each contained array
+ *   using obj.==.
+ *   Returns the first contained array that matches (that
+ *   is, the first assoc}iated array,
+ *   or +nil+ if no match is found.
+ *   See also Array.rassoc.
+ *
+ *     s1 = [ "colors", "red", "blue", "green" ]
+ *     s2 = [ "letters", "a", "b", "c" ]
+ *     s3 = "foo"
+ *     a  = [ s1, s2, s3 ]
+ *     a.assoc("letters")  #=> [ "letters", "a", "b", "c" ]
+ *     a.assoc("foo")      #=> nil
+ */
+
 VALUE
 rb_ary_assoc(ary, key)
     VALUE ary, key;
@@ -1659,6 +2361,20 @@ rb_ary_assoc(ary, key)
     return Qnil;
 }
 
+/*
+ *  call-seq:
+ *     array.rassoc(key) -> an_array or nil
+ *  
+ *  Searches through the array whose elements are also arrays. Compares
+ *  <em>key</em> with the second element of each contained array using
+ *  <code>==</code>. Returns the first contained array that matches. See
+ *  also <code>Array#assoc</code>.
+ *     
+ *     a = [ [ 1, "one"], [2, "two"], [3, "three"], ["ii", "two"] ]
+ *     a.rassoc("two")    #=> [2, "two"]
+ *     a.rassoc("four")   #=> nil
+ */
+
 VALUE
 rb_ary_rassoc(ary, value)
     VALUE ary, value;
@@ -1678,6 +2394,20 @@ rb_ary_rassoc(ary, value)
     return Qnil;
 }
 
+/* 
+ * call-seq:
+ *   array == other_array   =>   bool
+ *
+ *   Equality---Two arrays are equal if they contain the same number
+ *   of elements and if each element is equal to (according to
+ *   Object.==) the corresponding element in the other array.
+ *
+ *     [ "a", "c" ]    == [ "a", "c", 7 ]     #=> false
+ *     [ "a", "c", 7 ] == [ "a", "c", 7 ]     #=> true
+ *     [ "a", "c", 7 ] == [ "a", "d", "f" ]   #=> false
+ *
+ */
+
 static VALUE
 rb_ary_equal(ary1, ary2)
     VALUE ary1, ary2;
@@ -1731,6 +2461,19 @@ rb_ary_hash(ary)
     return LONG2FIX(h);
 }
 
+/*
+ *  call-seq:
+ *     array.include?(obj)   => true or false
+ *  
+ *  Returns <code>true</code> if the given object is present in
+ *  <i>self</i> (that is, if any object <code>==</code> <i>anObject</i>),
+ *  <code>false</code> otherwise.
+ *     
+ *     a = [ "a", "b", "c" ]
+ *     a.include?("b")   #=> true
+ *     a.include?("z")   #=> false
+ */
+
 VALUE
 rb_ary_includes(ary, item)
     VALUE ary;
@@ -1746,6 +2489,27 @@ rb_ary_includes(ary, item)
     return Qfalse;
 }
 
+
+/* 
+ * call-seq:
+ *   array <=> other_array   =>  -1, 0, +1
+ *
+ *   Comparison---Returns an integer (-1, 0,
+ *   or +1) if this array is less than, equal to, or greater than
+ *   other_array.  Each object in each array is compared
+ *   (using <=>). If any value isn't
+ *   equal, then that inequality is the return value. If all the
+ *   values found are equal, then the return is based on a
+ *   comparison of the array lengths.  Thus, two arrays are
+ *   ``equal'' according to Array.<=> if and only if they have
+ *   the same length and the value of each element is equal to the
+ *   value of the corresponding element in the other array.
+ *  
+ *     [ "a", "a", "c" ]    <=> [ "a", "b", "c" ]   #=> -1
+ *     [ 1, 2, 3, 4, 5, 6 ] <=> [ 1, 2 ]            #=> +1
+ *
+ */
+
 VALUE
 rb_ary_cmp(ary1, ary2)
     VALUE ary1, ary2;
@@ -1787,6 +2551,18 @@ ary_make_hash(ary1, ary2)
     return hash;
 }
 
+/* 
+ * call-seq:
+ *     array - other_array    => an_array
+ *
+ *   Array Difference---Returns a new array that is a copy of
+ *   the original array, removing any items that also appear in
+ *   other_array. (If you need set-like behavior, see the
+ *   library class Set.)
+ *
+ *     [ 1, 1, 2, 2, 3, 3, 4, 5 ] - [ 1, 2, 4 ]  #=>  [ 3, 3, 5 ]
+ */
+
 static VALUE
 rb_ary_diff(ary1, ary2)
     VALUE ary1, ary2;
@@ -1804,6 +2580,17 @@ rb_ary_diff(ary1, ary2)
     return ary3;
 }
 
+/* 
+ * call-seq:
+ *   array & other_array
+ *
+ *   Set Intersection---Returns a new array
+ *   containing elements common to the two arrays, with no duplicates.
+ *
+ *      [ 1, 1, 3, 5 ] & [ 1, 2, 3 ]   #=> [ 1, 3 ]
+ */
+
+
 static VALUE
 rb_ary_and(ary1, ary2)
     VALUE ary1, ary2;
@@ -1826,6 +2613,17 @@ rb_ary_and(ary1, ary2)
     return ary3;
 }
 
+/* 
+ * call-seq:
+ *    array | other_array     =>  an_array
+ *
+ *  Set Union---Returns a new array by joining this array with
+ *  other_array, removing duplicates.
+ *
+ *    [ "a", "b", "c" ] | [ "c", "d", "a" ]
+ *            #=> [ "a", "b", "c", "d" ]
+ */
+
 static VALUE
 rb_ary_or(ary1, ary2)
     VALUE ary1, ary2;
@@ -1853,6 +2651,20 @@ rb_ary_or(ary1, ary2)
     return ary3;
 }
 
+/*
+ *  call-seq:
+ *     array.uniq! => array or nil
+ *  
+ *  Removes duplicate elements from _self_.
+ *  Returns <code>nil</code> if no changes are made (that is, no
+ *  duplicates are found).
+ *     
+ *     a = [ "a", "a", "b", "b", "c" ]
+ *     a.uniq!   #=> ["a", "b", "c"]
+ *     b = [ "a", "b", "c" ]
+ *     b.uniq!   #=> nil
+ */
+
 static VALUE
 rb_ary_uniq_bang(ary)
     VALUE ary;
@@ -1881,6 +2693,16 @@ rb_ary_uniq_bang(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.uniq   => an_array
+ *  
+ *  Returns a new array by removing duplicate values in <i>self</i>.
+ *     
+ *     a = [ "a", "a", "b", "b", "c" ]
+ *     a.uniq   #=> ["a", "b", "c"]
+ */
+
 static VALUE
 rb_ary_uniq(ary)
     VALUE ary;
@@ -1890,6 +2712,16 @@ rb_ary_uniq(ary)
     return ary;
 }
 
+/* 
+ * call-seq:
+ *      array.compact!    =>   array  or  nil
+ *
+ *  Removes +nil+ elements from array.
+ *  Returns +niL+ if no changes were made.
+ *     [ "a", nil, "b", nil, "c" ].compact! #=> [ "a", "b", "c" ]
+ *     [ "a", "b", "c" ].compact!           #=> nil
+ */
+
 static VALUE
 rb_ary_compact_bang(ary)
     VALUE ary;
@@ -1913,6 +2745,16 @@ rb_ary_compact_bang(ary)
     return ary;
 }
 
+/* 
+ * call-seq:
+ *    array.compact     =>  an_array
+ *
+ * Returns a copy of _self_ with all +nil+ elements removed.
+ *   
+ *      [ "a", nil, "b", nil, "c", nil ].compact
+ *                       #=> [ "a", "b", "c" ]
+ */
+
 static VALUE
 rb_ary_compact(ary)
     VALUE ary;
@@ -1922,6 +2764,16 @@ rb_ary_compact(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.nitems -> int
+ *  
+ *  Returns the number of non-<code>nil</code> elements in _self_.
+ *  May be zero.
+ *     
+ *     [ 1, nil, 3, nil, 5 ].nitems   #=> 3
+ */
+
 static VALUE
 rb_ary_nitems(ary)
     VALUE ary;
@@ -1967,6 +2819,20 @@ flatten(ary, idx, ary2, memo)
     return lim - idx - 1;	/* returns number of increased items */
 }
 
+/*
+ *  call-seq:
+ *     arr.flatten! -> arr or nil
+ *  
+ *  Flattens _self_ in place.
+ *  Returns <code>nil</code> if no modifications were made (i.e.,
+ *  <i>arr</i> contains no subarrays.)
+ *     
+ *     a = [ 1, 2, [3, [4, 5] ] ]
+ *     a.flatten!   #=> [1, 2, 3, 4, 5]
+ *     a.flatten!   #=> nil
+ *     a            #=> [1, 2, 3, 4, 5]
+ */
+
 static VALUE
 rb_ary_flatten_bang(ary)
     VALUE ary;
@@ -1992,6 +2858,20 @@ rb_ary_flatten_bang(ary)
     return ary;
 }
 
+/*
+ *  call-seq:
+ *     array.flatten -> an_array
+ *  
+ *  Returns a new array that is a one-dimensional flattening of this
+ *  array (recursively). That is, for every element that is an array,
+ *  extract its elements into the new array.
+ *     
+ *     s = [ 1, 2, 3 ]           #=> [1, 2, 3]
+ *     t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
+ *     a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
+ *     a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10
+ */
+
 static VALUE
 rb_ary_flatten(ary)
     VALUE ary;
@@ -2001,6 +2881,14 @@ rb_ary_flatten(ary)
     return ary;
 }
 
+
+/* Arrays are ordered, integer-indexed collections of any object. 
+ * Array indexing starts at 0, as in C or Java.  A negative index is 
+ * assumed to be relative to the end of the array---that is, an index of -1 
+ * indicates the last element of the array, -2 is the next to last 
+ * element in the array, and so on. 
+ */
+
 void
 Init_Array()
 {