X-Git-Url: http://nitlanguage.org

diff --git a/lib/standard/kernel.nit b/lib/standard/kernel.nit
index 9dbdc25..dfff892 100644
--- a/lib/standard/kernel.nit
+++ b/lib/standard/kernel.nit
@@ -26,6 +26,28 @@ import end # Mark this module is a top level one. (must be only one)
 #
 # Currently, Object is also used to collect all top-level methods.
 interface Object
+	# Type of this instance, automatically specialized in every class
+	#
+	# A common use case of the virtual type `SELF` is to type an attribute and
+	# store another instance of the same type as `self`. It can also be used as as
+	# return type to a method producing a copy of `self` or returning an instance
+	# expected to be the exact same type as self.
+	#
+	# This virtual type must be used with caution as it can hinder specialization.
+	# In fact, it imposes strict restrictions on all sub-classes and their usage.
+	# For example, using `SELF` as a return type of a method `foo`
+	# forces all subclasses to ensure that `foo` returns the correct and updated
+	# type.
+	# A dangerous usage take the form of a method typed by `SELF` which creates
+	# and returns a new instance.
+	# If not correctly specialized, this method would break when invoked on a
+	# sub-class.
+	#
+	# A general rule for safe usage of `SELF` is to ensure that inputs typed
+	# `SELF` are stored in attributes typed `SELF` and returned by methods typed
+	# `SELF`, pretty much the same things as you would do with parameter types.
+	type SELF: Object
+
 	# The unique object identifier in the class.
 	# Unless specific code, you should not use this method.
 	# The identifier is used internally to provide a hash value.
@@ -40,13 +62,13 @@ interface Object
 	fun is_same_instance(other: nullable Object): Bool is intern
 
 	# Have `self` and `other` the same value?
-	##
+	#
 	# The exact meaning of "same value" is let to the subclasses.
 	# Implicitly, the default implementation, is `is_same_instance`
 	fun ==(other: nullable Object): Bool do return self.is_same_instance(other)
 
 	# Have `self` and `other` different values?
-	##
+	#
 	# != is equivalent with "not ==".
 	fun !=(other: nullable Object): Bool do return not (self == other)
 
@@ -65,15 +87,9 @@ interface Object
 	# only and can be removed without any notice
 	fun output_class_name is intern	
 
-	# Quit the program with a specific return code
-	protected fun exit(exit_value: Int) is intern
-
-	# Return the global sys object, the only instance of the `Sys` class.
-	protected fun sys: Sys is intern
-
 	# The hash code of the object.
 	# Assuming that a == b -> a.hash == b.hash
-	##
+	#
 	# Without redefinition, it is based on the `object_id` of the instance.
 	fun hash: Int do return object_id / 8
 end
@@ -84,8 +100,23 @@ end
 class Sys
 	# Instructions outside classes implicitly redefine this method.
 	fun main do end
+
+	# The entry point for the execution of the whole program.
+	# Its job is to call `main` but some modules may want to refine it
+	# and inject specific work before or after the main part.
+	fun run do main
+
+	# Number of the last error
+	fun errno: Int is extern "sys_errno"
 end
 
+# Quit the program with a specific return code
+fun exit(exit_value: Int) is intern
+
+# Return the global sys object, the only instance of the `Sys` class.
+fun sys: Sys is intern
+
+
 ###############################################################################
 # Abstract Classes                                                            #
 ###############################################################################
@@ -189,6 +220,25 @@ interface Discrete
 	end
 end
 
+# Something that can be cloned
+#
+# This interface introduces the `clone` method used to duplicate an instance
+# Its specific semantic is let to the subclasses.
+interface Cloneable
+	# Duplicate `self`
+	#
+	# The specific semantic of this method is let to the subclasses;
+	# Especially, if (and how) attributes are cloned (depth vs. shallow).
+	#
+	# As a rule of thumb, the principle of least astonishment should
+	# be used to guide the semantic.
+	#
+	# Note that as the returned clone depends on the semantic,
+	# the `==` method, if redefined, should ensure the equality
+	# between an object and its clone.
+	fun clone: SELF is abstract
+end
+
 # A numeric value supporting mathematical operations
 interface Numeric
 	super Comparable
@@ -224,6 +274,20 @@ interface Numeric
 	#     assert 5.to_f         == 5.0
 	#     assert 5.to_f         != 5 # Float and Int are not equals
 	fun to_f: Float is abstract
+
+	# Is this the value of zero in its domain?
+	fun is_zero: Bool do return self == zero
+
+	# The value of zero in the domain of `self`
+	fun zero: OTHER is abstract
+
+	# The value of `val` in the domain of `self`
+	#
+	#     assert 1.0.value_of(2) == 2.0
+	#     assert 1.0.value_of(2.0) == 2.0
+	#     assert 1.value_of(2) == 2
+	#     assert 1.value_of(2.0) == 2
+	fun value_of(val: Numeric): OTHER is abstract
 end
 
 ###############################################################################
@@ -232,15 +296,20 @@ end
 
 # Native Booleans.
 # `true` and `false` are the only instances.
+#
 # Boolean are manipulated trough three special operators:
-#	 `and`, `or`, `not`.
+# `and`, `or`, `not`.
+#
 # Booleans are mainly used by conditional statement and loops.
 universal Bool
 	redef fun object_id is intern
 	redef fun ==(b) is intern
 	redef fun !=(b) is intern
 	redef fun output is intern
-	redef fun hash
+	redef fun hash do return to_i
+
+	# 1 if true and 0 if false
+	fun to_i: Int
 	do
 		if self then
 			return 1
@@ -258,6 +327,8 @@ universal Float
 	redef type OTHER: Float
 
 	redef fun object_id is intern
+	redef fun ==(i) is intern
+	redef fun !=(i) is intern
 	redef fun output is intern
 
 	redef fun <=(i): Bool is intern
@@ -273,6 +344,62 @@ universal Float
 
 	redef fun to_i is intern
 	redef fun to_f do return self
+
+	redef fun zero do return 0.0
+	redef fun value_of(val) do return val.to_f
+
+	redef fun <=>(other)
+	do
+		if self < other then
+			return -1
+		else if other < self then
+			return 1
+		else
+			return 0
+		end
+	end
+
+	redef fun is_between(c, d)
+	do
+		if self < c or d < self then
+			return false
+		else
+			return true
+		end
+	end
+
+	# Compare float numbers with a given precision.
+	#
+	# Because of the loss of precision in floating numbers,
+	# the `==` method is often not the best way to compare them.
+	#
+	# ~~~
+	# assert 0.01.is_approx(0.02, 0.1)   == true
+	# assert 0.01.is_approx(0.02, 0.001) == false
+	# ~~~
+	fun is_approx(other, precision: Float): Bool
+	do
+		assert precision >= 0.0
+		return self <= other + precision and self >= other - precision
+	end
+
+	redef fun max(other)
+	do
+		if self < other then
+			return other
+		else
+			return self
+		end
+	end
+
+	redef fun min(c)
+	do
+		if c < self then
+			return c
+		else
+			return self
+		end
+	end
 end
 
 # Native integer numbers.
@@ -302,8 +429,18 @@ universal Int
 	redef fun -(i) is intern
 	redef fun *(i) is intern
 	redef fun /(i) is intern
+
+	# Modulo of `self` with `i`.
+	#
+	# Finds the remainder of division of `self` by `i`.
+	#
+	#     assert 5 % 2			== 1
+	#     assert 10 % 2			== 0
 	fun %(i: Int): Int is intern
 
+	redef fun zero do return 0
+	redef fun value_of(val) do return val.to_i
+
 	# `i` bits shift fo the left (aka <<)
 	#
 	#     assert 5.lshift(1)    == 10
@@ -367,8 +504,8 @@ universal Int
 
 	# The character whose ASCII value is `self`.
 	#
-	#      assert 65.ascii   == 'A'
-	#      assert 10.ascii   == '\n'
+	#     assert 65.ascii   == 'A'
+	#     assert 10.ascii   == '\n'
 	fun ascii: Char is intern
 
 	# Number of digits of an integer in base `b` (plus one if negative)
@@ -575,10 +712,29 @@ universal Char
 	do
 		return is_lower or is_upper
 	end
+
+	# Is self a whitespace character?
+	#
+	# These correspond to the "Other" and "Separator" groups of the Unicode.
+	#
+	# In the ASCII encoding, this is those <= to space (0x20) plus delete (0x7F).
+	#
+	#     assert 'A'.is_whitespace  == false
+	#     assert ','.is_whitespace  == false
+	#     assert ' '.is_whitespace  == true
+	#     assert '\t'.is_whitespace == true
+	fun is_whitespace: Bool
+	do
+		var i = ascii
+		return i <= 0x20 or i == 0x7F
+	end
 end
 
 # Pointer classes are used to manipulate extern C structures.
-extern Pointer
+extern class Pointer
 	# Is the address behind this Object at NULL?
-	fun address_is_null: Bool `{ return recv == NULL; `}
+	fun address_is_null: Bool is extern "address_is_null"
+
+	# Free the memory pointed by this pointer
+	fun free is extern "free"
 end