Replace Object.: with ：(U+FF1A) and ⫶ (U+2AF6)

Breaking change, to remove the `:` (colon)
    operator from Object.

Its use has been bisected into the ：
    (fat/fullwidth colon) and ⫶ (triple colon).

Previously the appearance of a `:` in the syntax
    was ambiguous, so it has been disambiguated
    to mean only NamedParam (when the LHS is a
    bareword) or Complex (when the LHS is a
    real number).

There is no direct overlap between these two
    syntaxes, but it's now possible to create
    a NamedParam with a real number as its name.

: remains as a first-class operator to create
    NamedParams using barewords, and to construct
    Complex literals.
- ：, the fullwidth colon U+FF1A: force creation
    of a Pair from self and the first argument.

- ⫶, the triple-colon operator U+2AF6: force
    creation of a NamedParam with the object
    on its LHS as the name.

    In other words, whereas the normal NamedParam
    colon operator expects a bareword on its LHS,
    the triple-colon evaluates its left hand side
    and therefore allows runtime-computed objects
    as the names in NamedParams, rather than
    forcing only barewords.

    Previously it was not possible to iterate an
    array of strings and generate NamedParams
    from them, because the : (colon) NamedParam
    operator (understandably) doesn't even accept
    a parenthesised expression on its LHS.

    Making NamedParam a directly invokable class
    would also be useful, but a shorthand is nice
    for this.

MANIFEST

@@ -848,6 +848,7 @@ scripts/Tests/objects_init.sf
 scripts/Tests/one-dimensional_cellular_automata.sf
 scripts/Tests/one-dimensional_cellular_automata_2.sf
 scripts/Tests/open.sf
+scripts/Tests/pair_namedparam_force_ops.sf
 scripts/Tests/pairs_test.sf
 scripts/Tests/palindrome_recursive.sf
 scripts/Tests/pascal_matrix_generation.sf

lib/Sidef/Object/Object.pm

@@ -367,11 +367,16 @@ package Sidef::Object::Object {
             $func->call($arg, @args);
         };
 
-        # Pair operator
-        *{__PACKAGE__ . '::' . ':'} = sub {
+        # Pair method: Fullwidth Colon; U+FF1A
+        *{__PACKAGE__ . '::' . '：'} = sub {
             Sidef::Types::Array::Pair->new($_[0], $_[1]);
         };
 
+        # NamedParam method: Triple Colon Operator; U+2AF6
+        *{__PACKAGE__ . '::' . '⫶'} = sub {
+            Sidef::Variable::NamedParam->new($_[0], $_[1]);
+        };
+
         # Logical AND
         *{__PACKAGE__ . '::' . '&&'} = sub {
             $_[0] ? $_[1] : $_[0];

lib/Sidef/Parser.pm

@@ -324,7 +324,7 @@ package Sidef::Parser {
                   ...
                   != ..
                   \\\\= \\\\
-                  !! ! : « » ~
+                  !! ! : ： ⫶ « » ~
                   );
 
                 qr{
@@ -1149,6 +1149,8 @@ package Sidef::Parser {
                 return Sidef::Types::String::String->new($1);
             }
 
+            # Bareword followed by a colon becomes a NamedParam with the bareword
+            # on the LHS
             if (/\G([^\W\d]\w*+):(?![=:])/gc) {
                 my $name = $1;
                 my $obj  = $self->parse_obj(code => $opt{code});

scripts/Tests/hash_concat.sf

@@ -14,7 +14,7 @@ assert_eq(hash{:a}, :b)
 hash += %w(c d)           # 2-item array
 assert_eq(hash{:c}, :d)
 
-hash += "2":3             # an actual Pair
+hash += "2"：3             # an actual Pair
 assert_eq(hash{"2"}, 3)
 
 say "** Test passed!"

scripts/Tests/pair_namedparam_force_ops.sf

@@ -0,0 +1,17 @@
+#! /usr/bin/ruby
+
+var f = :name
+assert_eq(f⫶ 1 -> dump, name: 1 -> dump)
+assert_eq(f⫶ 1 -> dump, (f)⫶ 1 -> dump)
+assert_eq((f)⫶ 1 -> dump, name: 1 -> dump)
+assert_eq(:a⫶ 1 -> dump, a:1 -> dump)
+
+var n = 1
+
+assert_ne(n: 2 -> dump, (n): 2 -> dump)
+assert_eq((n): 2 -> dump, 1: 2 -> dump)
+assert_eq(n：2, Pair(1, 2))
+assert_eq(1:2,  1+2i)
+assert_eq(1：2, Pair(1, 2))
+
+say "** Test passed!"

scripts/Tests/pairs_test.sf

@@ -4,7 +4,7 @@
 ## This script is used for testing only
 #
 
-var tree = 'root':'child':'grandchild':'end';
+var tree = 'root'：'child'：'grandchild'：'end';
 
 while (true) {
     say tree.first;

scripts/Tests/roman_numerals_decoding.sf

@@ -29,7 +29,7 @@ func roman2arabic (roman) {
 ## MAIN
 #
 
-['MCMXC':1990, 'MMVIII':2008, 'MDCLXVI':1666].each { |pair|
+[:MCMXC：1990, :MMVIII：2008, :MDCLXVI：1666].each { |pair|
 
     var arabic = roman2arabic(pair.first) == pair.second ||
         die "Error occurred on #{pair.first}\n";

scripts/Tests/roman_numerals_decoding_3.sf

@@ -2,19 +2,19 @@
 
 func roman2arabic(digit) {
     digit.uc.trans([
-        'M':  '1000+',
-        'CM':  '900+',
-        'D':   '500+',
-        'CD':  '400+',
-        'C':   '100+',
-        'XC':   '90+',
-        'L':    '50+',
-        'XL':   '40+',
-        'X':    '10+',
-        'IX':    '9+',
-        'V':     '5+',
-        'IV':    '4+',
-        'I':     '1+',
+        'M'：  '1000+',
+        'CM'：  '900+',
+        'D'：   '500+',
+        'CD'：  '400+',
+        'C'：   '100+',
+        'XC'：   '90+',
+        'L'：    '50+',
+        'XL'：   '40+',
+        'X'：    '10+',
+        'IX'：    '9+',
+        'V'：     '5+',
+        'IV'：    '4+',
+        'I'：     '1+',
     ]).split('+').map{.to_i}.sum;
 }
 

scripts/Tests/roman_numerals_encoding.sf

@@ -36,7 +36,7 @@ func arabic2roman (num) {
 ## MAIN
 #
 
-[[1990,'MCMXC'], [2008,'MMVIII'], [1666,'MDCLXVI']].each { |pair|
+[1990：:MCMXC, 2008：:MMVIII, 1666：:MDCLXVI].each { |pair|
     var roman = arabic2roman(pair[0]);
     roman == pair[1] || "Error occurred on number: #{pair[0]}\n".die;
     "%s in roman is %s".printlnf(pair[0], roman);

scripts/Tests/roman_numerals_encoding_2.sf

@@ -5,10 +5,10 @@
 func arabic2roman(num, roman='') {
 
     static lookup = [
-        :M:1000, :CM:900, :D:500,
-        :CD:400, :C:100, :XC:90,
-        :L:50, :XL:40, :X:10,
-        :IX:9, :V:5, :IV:4, :I:1
+        :M：1000, :CM：900, :D：500,
+        :CD：400, :C：100, :XC：90,
+        :L：50, :XL：40, :X：10,
+        :IX：9, :V：5, :IV：4, :I：1
     ];
 
     lookup.each { |pair|