2016 Update

Task/Optional-parameters/00DESCRIPTION

@@ -1,3 +1,4 @@
+;Task:
 Define a function/method/subroutine which sorts a sequence ("table") of sequences ("rows") of strings ("cells"), by one of the strings. Besides the input to be sorted, it shall have the following optional parameters:
 :{|
 |
@@ -17,3 +18,4 @@ Do not implement a sorting algorithm; this task is about the interface. If you c
 
 See also:
 * [[Named Arguments]]
+<br><br>

Task/Optional-parameters/ALGOL-68/optional-parameters.alg

@@ -0,0 +1,35 @@
+# as the options have distinct types (INT, BOOL and PROC( STRING, STRING )INT) the       #
+# easiest way to support these optional parameters in Algol 68 would be to have an array #
+# with elements of these types                                                           #
+# See the Named Arguments sample for cases where the option types are not distinct       #
+
+# default comparison function #
+PROC default compare = ( STRING a, b )INT: IF a < b THEN -1 ELIF a = b THEN 0 ELSE 1 FI;
+
+# sorting procedure #
+PROC configurable sort = ( [,]STRING data, []UNION( INT, BOOL, PROC( STRING, STRING )INT ) options )VOID:
+BEGIN
+    # set initial values for the options #
+    INT    sort column                   := 2 LWB data;
+    BOOL   reverse sort                  := FALSE;
+    PROC( STRING, STRING )INT comparator := default compare;
+    # overide from the supplied options #
+    FOR opt pos FROM LWB options TO UPB options DO
+        CASE options[ opt pos ]
+          IN ( PROC( STRING, STRING )INT p ): comparator   := p
+           , ( INT c ):                       sort column  := c
+           , ( BOOL r ):                      reverse sort := r
+        ESAC
+    OD
+    # do the sort .... #
+END # configurable sort # ;
+
+# example calls #
+[ 1 : 2, 1 : 3 ]STRING data := ( ( "a", "bb", "cde" ), ( "x", "abcdef", "Q" ) );
+
+# sort data, default comparison, first column, reverse order #
+configurable sort( data, ( TRUE ) );
+# sort data, second column, ignore first chaacter when sorting, normal order #
+configurable sort( data, ( 2, ( STRING a, STRING b )INT: default compare( a[ LWB a + 1 : ], b[ LWB b + 1 : ] ) ) );
+# default sort #
+configurable sort( data, () )

Task/Optional-parameters/Elixir/optional-parameters.elixir

@@ -0,0 +1,31 @@
+defmodule Optional_parameters do
+  def sort( table, options\\[] ) do
+    options = options ++ [ ordering: :lexicographic, column: 0, reverse: false ]
+    ordering = options[ :ordering ]
+    column   = options[ :column ]
+    reverse  = options[ :reverse ]
+    sorted = sort( table, ordering, column )
+    if reverse, do: Enum.reverse( sorted ), else: sorted
+  end
+
+  defp sort( table, :lexicographic, column ) do
+    Enum.sort_by( table, &elem( &1, column ) )
+  end
+  defp sort( table, :numeric, column ) do
+    Enum.sort_by( table, &elem( &1, column ) |> String.to_integer )
+  end
+
+  def task do
+    table = [ { "123", "456", "0789" },
+              { "456", "0789", "123" },
+              { "0789", "123", "456" } ]
+    IO.write "sort defaults "; IO.inspect sort( table )
+    IO.write " & reverse    "; IO.inspect sort( table, reverse: true )
+    IO.write "sort column 2 "; IO.inspect sort( table, column: 2)
+    IO.write " & reverse    "; IO.inspect sort( table, column: 2, reverse: true)
+    IO.write "sort numeric  "; IO.inspect sort( table, ordering: :numeric)
+    IO.write " & reverse    "; IO.inspect sort( table, ordering: :numeric, reverse: true)
+  end
+end
+
+Optional_parameters.task

Task/Optional-parameters/Lua/optional-parameters.lua

@@ -0,0 +1,43 @@
+function showTable(tbl)
+	if type(tbl)=='table' then
+		local result = {}
+		for _, val in pairs(tbl) do
+			table.insert(result, showTable(val))
+		end
+		return '{' .. table.concat(result, ', ') .. '}'
+	else
+		return (tostring(tbl))
+	end
+end
+
+function sortTable(op)
+	local tbl = op.table or {}
+	local column = op.column or 1
+	local reverse = op.reverse or false
+	local cmp = op.cmp or (function (a, b) return a < b end)
+	local compareTables = function (a, b)
+		local result = cmp(a[column], b[column])
+		if reverse then return not result else return result end
+	end
+	table.sort(tbl, compareTables)
+end
+
+A = {{"quail", "deer", "snake"},
+	{"dalmation", "bear", "fox"},
+	{"ant", "cougar", "coyote"}}
+print('original', showTable(A))
+
+sortTable{table=A}
+print('defaults', showTable(A))
+
+sortTable{table=A, column=2}
+print('col 2    ', showTable(A))
+
+sortTable{table=A, column=3}
+print('col 3    ', showTable(A))
+
+sortTable{table=A, column=3, reverse=true}
+print('col 3 rev', showTable(A))
+
+sortTable{table=A, cmp=(function (a, b) return #a < #b end)}
+print('by length', showTable(A))