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

diff --git a/lib/standard/kernel.nit b/lib/standard/kernel.nit
index 64de7c3..fb84d2e 100644
--- a/lib/standard/kernel.nit
+++ b/lib/standard/kernel.nit
@@ -11,35 +11,52 @@
 # You  are  allowed  to  redistribute it and sell it, alone or is a part of
 # another product.
 
+# Most minimal classes and methods.
 # This module is the root of the standard module hierarchy.
-package kernel
+module kernel
 
 import end # Mark this module is a top level one. (must be only one)
 
+`{
+#include <errno.h>
+`}
+
 ###############################################################################
 # System Classes                                                              #
 ###############################################################################
 
 # The root of the class hierarchy.
-# Each class implicitely specialize Object.
+# Each class implicitly specialize Object.
+#
+# Currently, Object is also used to collect all top-level methods.
 interface Object
-	# The unique object identifier in the class
+	# 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.
 	fun object_id: Int is intern
 
-	# Return true is `self' and `other' have the same dynamic type
+	# Return true if `self` and `other` have the same dynamic type.
+	# Unless specific code, you should not use this method.
 	fun is_same_type(other: Object): Bool is intern
 
-	# Have `self' and `other' the same value?
+	# Return true if `self` and `other` are the same instance.
+	# Unless specific code, you should use `==` instead.
+	fun is_same_instance(other: nullable Object): Bool is intern
+
+	# Have `self` and `other` the same value?
 	##
-	# Implicitely, the default implementation, is ==
-	fun ==(other: nullable Object): Bool do return self is other
+	# 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?
+	# Have `self` and `other` different values?
 	##
-	# != is equivament with "not =".
+	# != is equivalent with "not ==".
 	fun !=(other: nullable Object): Bool do return not (self == other)
 
 	# Display self on stdout (debug only).
+	# This method MUST not be used by programs, it is here for debugging
+	# only and can be removed without any notice
 	fun output
 	do
 		'<'.output
@@ -47,14 +64,35 @@ interface Object
 		'>'.output
 	end
 
-	protected fun exit(exit_value: Int) is intern # Quit the program.
-	protected fun sys: Sys is intern # The global sys object
+	# Display class name on stdout (debug only).
+	# This method MUST not be used by programs, it is here for debugging
+	# 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
 
 # The main class of the program.
+# `Sys` is a singleton class, its only instance is `sys` defined in `Object`.
+# `sys` is used to invoke methods on the program on the system.
 class Sys
-	# Instructions outside classes implicetely redefine this method.
+	# Instructions outside classes implicitly redefine this method.
 	fun main do end
+
+	# Number of the last error
+	fun errno: Int is extern `{
+		return errno;
+	`}
 end
 
 ###############################################################################
@@ -64,21 +102,25 @@ end
 # The ancestor of class where objects are in a total order.
 # In order to work, the method '<' has to be redefined.
 interface Comparable
+	# What `self` can be compared to?
 	type OTHER: Comparable
 
-	# Is `self' lesser than `other'
+	# Is `self` lesser than `other`?
 	fun <(other: OTHER): Bool is abstract 
 
-	# not `other' < `self'
+	# not `other` < `self`
+	# Note, the implementation must ensure that: `(x<=y) == (x<y or x==y)`
 	fun <=(other: OTHER): Bool do return not other < self
 
-	# not `self' < `other' 
+	# not `self` < `other`
+	# Note, the implementation must ensure that: `(x>=y) == (x>y or x==y)`
 	fun >=(other: OTHER): Bool do return not self < other
 
-	# `other' < `self'
+	# `other` < `self`
 	fun >(other: OTHER): Bool do return other < self
 
 	# -1 if <, +1 if > and 0 otherwise
+	# Note, the implementation must ensure that: (x<=>y == 0) == (x==y)
 	fun <=>(other: OTHER): Int
 	do
 		if self < other then
@@ -96,7 +138,7 @@ interface Comparable
 		return c <= self and self <= d
 	end
 
-	# The maximum between `self' and `other' (prefers `self' if equals).
+	# The maximum between `self` and `other` (prefers `self` if equals).
 	fun max(other: OTHER): OTHER
 	do
 		if self < other then
@@ -106,7 +148,7 @@ interface Comparable
 		end
 	end
 
-	# The minimum between `self' and `c' (prefer `self' if equals)
+	# The minimum between `self` and `c` (prefer `self` if equals)
 	fun min(c: OTHER): OTHER
 	do
 		if c < self then
@@ -119,25 +161,20 @@ end
 
 # Discrete total orders.
 interface Discrete
-special Comparable
+	super Comparable
 
 	redef type OTHER: Discrete
 
 	# The next element.
-	fun succ: OTHER do return self + 1
+	fun successor(i: Int): OTHER is abstract
 
 	# The previous element.
-	fun prec: OTHER do return self - 1
-
-	# The `i' th successor element.
-	fun +(i: Int): OTHER is abstract
-
-	# The `i' th previous element.
-	fun -(i: Int): OTHER is abstract
+	fun predecessor(i: Int): OTHER is abstract
 
 	# The distance between self and d.
-	# 10.distance(15)	# --> 5
-	# 'Z'.distance('A')	# --> 25
+	#
+	#     assert 10.distance(15)	     ==  5
+	#     assert 'Z'.distance('A')	     ==  25
 	fun distance(d: OTHER): Int
 	do
 		var cursor: OTHER
@@ -154,56 +191,132 @@ special Comparable
 
 		var nb = 0
 		while cursor < stop do
-			cursor = cursor.succ
+			cursor = cursor.successor(1)
 			nb += 1
 		end
 		return nb
 	end
 end
 
+# A numeric value supporting mathematical operations
+interface Numeric
+	super Comparable
+
+	redef type OTHER: Numeric
+
+	# Addition of `self` with `i`
+	fun +(i: OTHER): OTHER is abstract
+
+	# Substraction of `i` from `self`
+	fun -(i: OTHER): OTHER is abstract
+
+	# Inverse of `self`
+	fun -: OTHER is abstract
+
+	# Multiplication of `self` with `i`
+	fun *(i: OTHER): OTHER is abstract
+
+	# Division of `self` with `i`
+	fun /(i: OTHER): OTHER is abstract
+
+	# The integer part of `self`.
+	#
+	#     assert (0.0).to_i      == 0
+	#     assert (0.9).to_i      == 0
+	#     assert (-0.9).to_i     == 0
+	#     assert (9.9).to_i      == 9
+	#     assert (-9.9).to_i     == -9
+	fun to_i: Int is abstract
+
+	# The float equivalent of `self`
+	#
+	#     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
+
 ###############################################################################
 # Native classes                                                              #
 ###############################################################################
 
-# Native booleans.
-# `true' and `false' are the only instances.
-# Boolean are manipulated trought three special operators:
-#	 `and', `or', `not'.
+# Native Booleans.
+# `true` and `false` are the only instances.
+# Boolean are manipulated trough three special operators:
+#	 `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 do return to_i
+
+	# 1 if true and 0 if false
+	fun to_i: Int
+	do
+		if self then
+			return 1
+		else
+			return 0
+		end
+	end
 end
 
 # Native floating point numbers.
 # Corresponds to C float.
 universal Float
+	super Numeric
+
+	redef type OTHER: Float
+
 	redef fun object_id is intern
 	redef fun output is intern
 
-	fun <=(i: Float): Bool is intern
-	fun <(i: Float): Bool is intern
-	fun >=(i: Float): Bool is intern
-	fun >(i: Float): Bool is intern
-	fun +(i: Float): Float is intern
-	fun -: Float is intern
-	fun -(i: Float): Float is intern
-	fun *(i: Float): Float is intern
-	fun /(i: Float): Float is intern
-	
-	# The integer part of `self'.
-	fun to_i: Int is intern
+	redef fun <=(i): Bool is intern
+	redef fun <(i): Bool is intern
+	redef fun >=(i): Bool is intern
+	redef fun >(i): Bool is intern
+
+	redef fun +(i) is intern
+	redef fun - is intern
+	redef fun -(i) is intern
+	redef fun *(i) is intern
+	redef fun /(i) is intern
+
+	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
 end
 
 # Native integer numbers.
 # Correspond to C int.
 universal Int
-special Discrete
+	super Discrete
+	super Numeric
+
 	redef type OTHER: Int
 
+	redef fun successor(i) do return self + i
+	redef fun predecessor(i) do return self - i
+
 	redef fun object_id is intern
+	redef fun hash do return self
 	redef fun ==(i) is intern
 	redef fun !=(i) is intern
 	redef fun output is intern
@@ -213,19 +326,29 @@ special Discrete
 	redef fun >=(i) is intern
 	redef fun >(i) is intern
 	redef fun +(i) is intern
-	fun -: Int is intern
+
+	redef fun - is intern
 	redef fun -(i) is intern
-	fun *(i: Int): Int is intern
-	fun /(i: Int): Int is intern
-	fun %(i: Int): Int is intern   
+	redef fun *(i) is intern
+	redef fun /(i) is intern
+	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
 	fun lshift(i: Int): Int is intern
-	fun rshift(i: Int): Int is intern   
 
-	# The float equivalent of `self'
-	fun to_f: Float is intern
+	# `i` bits shift fo the right (aka >>)
+	#
+	#     assert 5.rshift(1)    == 2
+	fun rshift(i: Int): Int is intern
+
+	redef fun to_i do return self
+	redef fun to_f is intern
 
-	redef fun succ is intern
-	redef fun prec is intern
 	redef fun distance(i)
 	do
 		var d = self - i
@@ -235,7 +358,7 @@ special Discrete
 			return -d
 		end
 	end
-	
+
 	redef fun <=>(other)
 	do
 		if self < other then
@@ -274,12 +397,19 @@ special Discrete
 		end
 	end
 
-	# The character whose ASCII value is `self'.
+	# The character whose ASCII value is `self`.
+	#
+	#      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)
+	# Number of digits of an integer in base `b` (plus one if negative)
+	#
+	#     assert 123.digit_count(10) == 3
+	#     assert 123.digit_count(2) == 7 # 1111011 in binary
 	fun digit_count(b: Int): Int
 	do
+		if b == 10 then return digit_count_base_10
 		var d: Int # number of digits
 		var n: Int # current number
 		# Sign
@@ -295,14 +425,38 @@ special Discrete
 		# count digits
 		while n > 0 do
 			d += 1
-			n = n / b  	# euclidian division /		
+			n = n / b  	# euclidian division /
 		end
 		return d
 	end
 
+	# Optimized version for base 10
+	fun digit_count_base_10: Int
+	do
+		var val: Int
+		var result: Int
+		if self < 0 then
+			result = 2
+			val = -self
+		else
+			result = 1
+			val = self
+		end
+		loop
+			if val < 10 then return result
+			if val < 100 then return result+1
+			if val < 1000 then return result+2
+			if val < 10000 then return result+3
+			val = val / 10000
+			result += 4
+		end
+	end
+
 	# Return the corresponding digit character
-	# If 0 <= `self' <= 9, return the corresponding character.
-	# If 10 <= `self' <= 36, return the corresponding letter [a..z].
+	# If 0 <= `self` <= 9, return the corresponding character.
+	#     assert 5.to_c    == '5'
+	# If 10 <= `self` <= 36, return the corresponding letter [a..z].
+	#     assert 15.to_c   == 'f'
 	fun to_c: Char
 	do
 		assert self >= 0 and self <= 36 # TODO plan for this
@@ -312,16 +466,32 @@ special Discrete
 			return (self + ('a'.ascii - 10)).ascii
 		end
 	end
+
+	# The absolute value of self
+	#
+	#     assert (-10).abs   == 10
+	#     assert 10.abs    == 10
+	#     assert 0.abs     == 0
+	fun abs: Int
+	do
+	    if self >= 0
+	    then
+	        return self
+	    else
+	        return -1 * self
+	    end
+	end
 end
 
 # Native characters.
 # Characters are denoted with simple quote.
-# eg. 'a' or '\n'.
+# eg. `'a'` or `'\n'`.
 universal Char
-special Discrete
+	super Discrete
 	redef type OTHER: Char
 
 	redef fun object_id is intern
+	redef fun hash do return ascii
 	redef fun ==(o) is intern
 	redef fun !=(o) is intern
 	redef fun output is intern
@@ -331,8 +501,8 @@ special Discrete
 	redef fun >=(i) is intern
 	redef fun >(i) is intern
 
-	redef fun succ is intern
-	redef fun prec is intern
+	redef fun successor(i) is intern
+	redef fun predecessor(i) is intern
 
 	redef fun distance(c)
 	do
@@ -344,46 +514,106 @@ special Discrete
 		end
 	end
 
-	# If `self' is a digit then return this digit.
+	# If `self` is a digit then return this digit else return -1.
+	#
+	#     assert '5'.to_i    == 5
 	fun to_i: Int
 	do
 
 		if self == '-' then
 			return -1
-		else if self >= '0' and self <= '9' then
+		else if is_digit then
 			return self.ascii - '0'.ascii
 		else
-			return self.to_lower.ascii - ('a'.ascii + 10)
+			return self.to_lower.ascii - 'a'.ascii + 10
 		end
 	end
 
 	# the ascii value of self
+	#
+	#     assert 'a'.ascii    == 97
+	#     assert '\n'.ascii   == 10
 	fun ascii: Int is intern
 
-	redef fun +(i) is intern
-	redef fun -(i) is intern
-
-	# Char to lower case
-	fun to_lower : Char
+	# Return the lower case version of self.
+	# If self is not a letter, then return self
+	#
+	#     assert 'A'.to_lower  == 'a'
+	#     assert 'a'.to_lower  == 'a'
+	#     assert '$'.to_lower  == '$'
+	fun to_lower: Char
 	do
-		if self >= 'A' and self <= 'Z' then
+		if is_upper then
 			return (ascii + ('a'.distance('A'))).ascii
 		else
 			return self
 		end
 	end
 
-	# Char to upper case
-	fun to_upper : Char
+	# Return the upper case version of self.
+	# If self is not a letter, then return self
+	#
+	#     assert 'a'.to_upper  == 'A'
+	#     assert 'A'.to_upper  == 'A'
+	#     assert '$'.to_upper  == '$'
+	fun to_upper: Char
 	do
-		if self >= 'a' and self <= 'z' then
+		if is_lower then
 			return (ascii - ('a'.distance('A'))).ascii
 		else
 			return self
 		end
 	end
+
+	# Is self a digit? (from '0' to '9')
+	#
+	#     assert '0'.is_digit   == true
+	#     assert '9'.is_digit   == true
+	#     assert 'a'.is_digit   == false
+	fun is_digit : Bool
+	do
+		return self >= '0' and self <= '9'
+	end
+
+	# Is self a lower case letter? (from 'a' to 'z')
+	#
+	#     assert 'a'.is_lower   == true
+	#     assert 'z'.is_lower   == true
+	#     assert 'A'.is_lower   == false
+	#     assert '$'.is_lower   == false
+	fun is_lower : Bool
+	do
+		return self >= 'a' and self <= 'z'
+	end
+
+	# Is self a upper case letter? (from 'A' to 'Z')
+	#
+	#     assert 'A'.is_upper   == true
+	#     assert 'A'.is_upper   == true
+	#     assert 'z'.is_upper   == false
+	#     assert '$'.is_upper   == false
+	fun is_upper : Bool
+	do
+		return self >= 'A' and self <= 'Z'
+	end
+
+	# Is self a letter? (from 'A' to 'Z' and 'a' to 'z')
+	#
+	#     assert 'A'.is_letter  == true
+	#     assert 'A'.is_letter  == true
+	#     assert 'z'.is_letter  == true
+	#     assert '$'.is_letter  == false
+	fun is_letter : Bool
+	do
+		return is_lower or is_upper
+	end
 end
 
 # Pointer classes are used to manipulate extern C structures.
-universal Pointer
+extern class Pointer
+	# Is the address behind this Object at NULL?
+	fun address_is_null: Bool is extern "address_is_null"
+
+	# Free the memory pointed by this pointer
+	fun free `{ free(recv); `}
 end