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-rw-r--r--enum.c334
1 files changed, 334 insertions, 0 deletions
diff --git a/enum.c b/enum.c
index ee0b058..28f28cb 100644
--- a/enum.c
+++ b/enum.c
@@ -44,6 +44,24 @@ grep_iter_i(i, arg)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.grep(pattern) => array
+ * enum.grep(pattern) {| obj | block } => array
+ *
+ * Returns an array of every element in <i>enum</i> for which
+ * <code>Pattern === element</code>. If the optional <em>block</em> is
+ * supplied, each matching element is passed to it, and the block's
+ * result is stored in the output array.
+ *
+ * (1..100).grep 38..44 #=> [38, 39, 40, 41, 42, 43, 44]
+ * c = IO.constants
+ * c.grep(/SEEK/) #=> ["SEEK_END", "SEEK_SET", "SEEK_CUR"]
+ * res = c.grep(/SEEK/) {|v| IO.const_get(v) }
+ * res #=> [2, 0, 1]
+ *
+ */
+
static VALUE
enum_grep(obj, pat)
VALUE obj, pat;
@@ -72,6 +90,20 @@ find_i(i, memo)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.detect {| obj | block } => obj or nil
+ * enum.find {| obj | block } => obj or nil
+ *
+ * Passes each entry in <i>enum</i> to <em>block</em>. Returns the
+ * first for which <em>block</em> is not <code>false</code>. Returns
+ * <code>nil</code> if no object matches.
+ *
+ * (1..10).detect {|i| i % 5 == 0 and i % 7 == 0 } #=> nil
+ * (1..100).detect {|i| i % 5 == 0 and i % 7 == 0 } #=> 35
+ *
+ */
+
static VALUE
enum_find(argc, argv, obj)
int argc;
@@ -105,6 +137,19 @@ find_all_i(i, ary)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.find_all {| obj | block } => array
+ * enum.select {| obj | block } => array
+ *
+ * Returns an array containing all elements of <i>enum</i> for which
+ * <em>block</em> is not <code>false</code> (see also
+ * <code>Enumerable#reject</code>).
+ *
+ * (1..10).find_all {|i| i % 3 == 0 } #=> [3, 6, 9]
+ *
+ */
+
static VALUE
enum_find_all(obj)
VALUE obj;
@@ -126,6 +171,17 @@ reject_i(i, ary)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.reject {| obj | block } => array
+ *
+ * Returns an array for all elements of <i>enum</i> for which
+ * <em>block</em> is false (see also <code>Enumerable#find_all</code>).
+ *
+ * (1..10).reject {|i| i % 3 == 0 } #=> [1, 2, 4, 5, 7, 8, 10]
+ *
+ */
+
static VALUE
enum_reject(obj)
VALUE obj;
@@ -155,6 +211,19 @@ collect_all(i, ary)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.collect {| obj | block } => array
+ * enum.map {| obj | block } => array
+ *
+ * Returns a new array with the results of running <em>block</em> once
+ * for every element in <i>enum</i>.
+ *
+ * (1..4).collect {|i| i*i } #=> [1, 4, 9, 16]
+ * (1..4).collect { "cat" } #=> ["cat", "cat", "cat", "cat"]
+ *
+ */
+
static VALUE
enum_collect(obj)
VALUE obj;
@@ -166,6 +235,16 @@ enum_collect(obj)
return ary;
}
+/*
+ * call-seq:
+ * enum.to_a => array
+ * enum.entries => array
+ *
+ * Returns an array containing the items in <i>enum</i>.
+ *
+ * (1..7).to_a #=> [1, 2, 3, 4, 5, 6, 7]
+ * { 'a'=>1, 'b'=>2, 'c'=>3 }.to_a #=> [["a", 1], ["b", 2], ["c", 3]]
+ */
static VALUE
enum_to_a(obj)
VALUE obj;
@@ -192,6 +271,37 @@ inject_i(i, memo)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.inject(initial) {| memo, obj | block } => obj
+ * enum.inject {| memo, obj | block } => obj
+ *
+ * Combines the elements of <i>enum</i> by applying the block to an
+ * accumulator value (<i>memo</i>) and each element in turn. At each
+ * step, <i>memo</i> is set to the value returned by the block. The
+ * first form lets you supply an initial value for <i>memo</i>. The
+ * second form uses the first element of the collection as a the
+ * initial value (and skips that element while iterating).
+ *
+ * # Sum some numbers
+ * (5..10).inject {|sum, n| sum + n } #=> 45
+ * # Multiply some numbers
+ * (5..10).inject(1) {|product, n| product * n } #=> 151200
+ *
+ * # find the longest word
+ * longest = %w{ cat sheep bear }.inject do |memo,word|
+ * memo.length > word.length ? memo : word
+ * end
+ * longest #=> "sheep"
+ *
+ * # find the length of the longest word
+ * longest = %w{ cat sheep bear }.inject(0) do |memo,word|
+ * memo >= word.length ? memo : word.length
+ * end
+ * longest #=> 5
+ *
+ */
+
static VALUE
enum_inject(argc, argv, obj)
int argc;
@@ -225,6 +335,18 @@ partition_i(i, ary)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.partition {| obj | block } => [ true_array, false_array ]
+ *
+ * Returns two arrays, the first containing the elements of
+ * <i>enum</i> for which the block evaluates to true, the second
+ * containing the rest.
+ *
+ * (1..6).partition {|i| (i&1).zero?} #=> [[2, 4, 6], [1, 3, 5]]
+ *
+ */
+
static VALUE
enum_partition(obj)
VALUE obj;
@@ -238,6 +360,23 @@ enum_partition(obj)
return rb_assoc_new(ary[0], ary[1]);
}
+/*
+ * call-seq:
+ * enum.sort => array
+ * enum.sort {| a, b | block } => array
+ *
+ * Returns an array containing the items in <i>enum</i> sorted,
+ * either according to their own <code><=></code> method, or by using
+ * the results of the supplied block. The block should return -1, 0, or
+ * +1 depending on the comparison between <i>a</i> and <i>b</i>. As of
+ * Ruby 1.8, the method <code>Enumerable#sort_by</code> implements a
+ * built-in Schwartzian Transform, useful when key computation or
+ * comparison is expensive..
+ *
+ * %w(rhea kea flea).sort #=> ["flea", "kea", "rhea"]
+ * (1..10).sort {|a,b| b <=> a} #=> [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
+ */
+
static VALUE
enum_sort(obj)
VALUE obj;
@@ -267,6 +406,75 @@ sort_by_cmp(a, b)
return rb_cmpint(retval, *a, *b);
}
+/*
+ * call-seq:
+ * enum.sort_by {| obj | block } => array
+ *
+ * Sorts <i>enum</i> using a set of keys generated by mapping the
+ * values in <i>enum</i> through the given block.
+ *
+ * %w{ apple pear fig }.sort_by {|word| word.length}
+ #=> ["fig", "pear", "apple"]
+ *
+ * The current implementation of <code>sort_by</code> generates an
+ * array of tuples containing the original collection element and the
+ * mapped value. This makes <code>sort_by</code> fairly expensive when
+ * the keysets are simple
+ *
+ * require 'benchmark'
+ * include Benchmark
+ *
+ * a = (1..100000).map {rand(100000)}
+ *
+ * bm(10) do |b|
+ * b.report("Sort") { a.sort }
+ * b.report("Sort by") { a.sort_by {|a| a} }
+ * end
+ *
+ * <em>produces:</em>
+ *
+ * user system total real
+ * Sort 0.180000 0.000000 0.180000 ( 0.175469)
+ * Sort by 1.980000 0.040000 2.020000 ( 2.013586)
+ *
+ * However, consider the case where comparing the keys is a non-trivial
+ * operation. The following code sorts some files on modification time
+ * using the basic <code>sort</code> method.
+ *
+ * files = Dir["*"]
+ * sorted = files.sort {|a,b| File.new(a).mtime <=> File.new(b).mtime}
+ * sorted #=> ["mon", "tues", "wed", "thurs"]
+ *
+ * This sort is inefficient: it generates two new <code>File</code>
+ * objects during every comparison. A slightly better technique is to
+ * use the <code>Kernel#test</code> method to generate the modification
+ * times directly.
+ *
+ * files = Dir["*"]
+ * sorted = files.sort { |a,b|
+ * test(?M, a) <=> test(?M, b)
+ * }
+ * sorted #=> ["mon", "tues", "wed", "thurs"]
+ *
+ * This still generates many unnecessary <code>Time</code> objects. A
+ * more efficient technique is to cache the sort keys (modification
+ * times in this case) before the sort. Perl users often call this
+ * approach a Schwartzian Transform, after Randal Schwartz. We
+ * construct a temporary array, where each element is an array
+ * containing our sort key along with the filename. We sort this array,
+ * and then extract the filename from the result.
+ *
+ * sorted = Dir["*"].collect { |f|
+ * [test(?M, f), f]
+ * }.sort.collect { |f| f[1] }
+ * sorted #=> ["mon", "tues", "wed", "thurs"]
+ *
+ * This is exactly what <code>sort_by</code> does internally.
+ *
+ * sorted = Dir["*"].sort_by {|f| test(?M, f)}
+ * sorted #=> ["mon", "tues", "wed", "thurs"]
+ */
+
static VALUE
enum_sort_by(obj)
VALUE obj;
@@ -315,6 +523,23 @@ all_i(i, memo)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.all? [{|obj| block } ] => true or false
+ *
+ * Passes each element of the collection to the given block. The method
+ * returns <code>true</code> if the block never returns
+ * <code>false</code> or <code>nil</code>. If the block is not given,
+ * Ruby adds an implicit block of <code>{|obj| obj}</code> (that is
+ * <code>all?</code> will return <code>true</code> only if none of the
+ * collection members are <code>false</code> or <code>nil</code>.)
+ *
+ * %w{ ant bear cat}.all? {|word| word.length >= 3} #=> true
+ * %w{ ant bear cat}.all? {|word| word.length >= 4} #=> false
+ * [ nil, true, 99 ].all? #=> false
+ *
+ */
+
static VALUE
enum_all(obj)
VALUE obj;
@@ -353,6 +578,24 @@ any_i(i, memo)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.any? [{|obj| block } ] => true or false
+ *
+ * Passes each element of the collection to the given block. The method
+ * returns <code>true</code> if the block ever returns a value other
+ * that <code>false</code> or <code>nil</code>. If the block is not
+ * given, Ruby adds an implicit block of <code>{|obj| obj}</code> (that
+ * is <code>any?</code> will return <code>true</code> if at least one
+ * of the collection members is not <code>false</code> or
+ * <code>nil</code>.
+ *
+ * %w{ ant bear cat}.any? {|word| word.length >= 3} #=> true
+ * %w{ ant bear cat}.any? {|word| word.length >= 4} #=> true
+ * [ nil, true, 99 ].any? #=> true
+ *
+ */
+
static VALUE
enum_any(obj)
VALUE obj;
@@ -405,6 +648,21 @@ min_ii(i, memo)
return Qnil;
}
+
+/*
+ * call-seq:
+ * enum.min => obj
+ * enum.min {| a,b | block } => obj
+ *
+ * Returns the object in <i>enum</i> with the minimum value. The
+ * first form assumes all objects implement <code>Comparable</code>;
+ * the second uses the block to return <em>a <=> b</em>.
+ *
+ * a = %w(albatross dog horse)
+ * a.min #=> "albatross"
+ * a.max {|a,b| a.length <=> b.length } #=> "dog"
+ */
+
static VALUE
enum_min(obj)
VALUE obj;
@@ -418,6 +676,20 @@ enum_min(obj)
return result;
}
+/*
+ * call-seq:
+ * enum.max => obj
+ * enum.max {| a,b | block } => obj
+ *
+ * Returns the object in <i>enum</i> with the maximum value. The
+ * first form assumes all objects implement <code>Comparable</code>;
+ * the second uses the block to return <em>a <=> b</em>.
+ *
+ * a = %w(albatross dog horse)
+ * a.max #=> "horse"
+ * a.max {|a,b| a.length <=> b.length } #=> "albatross"
+ */
+
static VALUE
max_i(i, memo)
VALUE i;
@@ -481,6 +753,19 @@ member_i(item, memo)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.include?(obj) => true or false
+ * enum.member?(obj) => true or false
+ *
+ * Returns <code>true</code> if any member of <i>enum</i> equals
+ * <i>obj</i>. Equality is tested using <code>==</code>.
+ *
+ * IO.constants.include? "SEEK_SET" #=> true
+ * IO.constants.include? "SEEK_NO_FURTHER" #=> false
+ *
+ */
+
static VALUE
enum_member(obj, val)
VALUE obj, val;
@@ -504,6 +789,21 @@ each_with_index_i(val, memo)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.each_with_index {|obj, i| block } -> nil
+ *
+ * Calls <em>block</em> with two arguments, the item and its index, for
+ * each item in <i>enum</i>.
+ *
+ * hash = Hash.new
+ * %w(cat dog wombat).each_with_index {|item, index|
+ * hash[item] = index
+ * }
+ * hash #=> {"cat"=>0, "wombat"=>2, "dog"=>1}
+ *
+ */
+
static VALUE
enum_each_with_index(obj)
VALUE obj;
@@ -540,6 +840,29 @@ zip_i(val, memo)
return Qnil;
}
+/*
+ * call-seq:
+ * enum.zip(arg, ...) => array
+ * enum.zip(arg, ...) {|arr| block } => nil
+ *
+ * Converts any arguments to arrays, then merges elements of
+ * <i>enum</i> with corresponding elements from each argument. This
+ * generates a sequence of <code>enum#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>enum#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..3).zip(a, b) #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
+ * "cat\ndog".zip([1]) #=> [["cat\n", 1], ["dog", nil]]
+ * (1..3).zip #=> [[1], [2], [3]]
+ *
+ */
+
static VALUE
enum_zip(argc, argv, obj)
int argc;
@@ -560,6 +883,17 @@ enum_zip(argc, argv, obj)
return result;
}
+/*
+ * The <code>Enumerable</code> mixin provides collection classes with
+ * several traversal and searching methods, and with the ability to
+ * sort. The class must provide a method <code>each</code>, which
+ * yields successive members of the collection. If
+ * <code>Enumerable#max</code>, <code>#min</code>, or
+ * <code>#sort</code> is used, the objects in the collection must also
+ * implement a meaningful <code><=></code> operator, as these methods
+ * rely on an ordering between members of the collection.
+ */
+
void
Init_Enumerable()
{