TODO-perlito5

TODO list for Perlito5


* perlito5 command-line


* libraries

-- these should probably go into namespace Perlito5X::*

-- Test (implemented as Perlito5::Test)

-- Data::Dumper (implemented as Perlito5::Dumper)

-- create perlito5-specific libs for:
    feature.pm
    Config.pm
    overload.pm
    bytes.pm
    integer.pm
    constant.pm
    lib.pm
    Carp.pm
    vars.pm
    Tie::Array
    Tie::Hash
    Tie::Scalar

    alternately, check $^H for strictness - such that perl's own strict.pm just works
    and ${^WARNING_BITS} for warnings


* Parser

-- attributes
    http://perldoc.perl.org/attributes.html

-- create __DATA__
    http://perldoc.perl.org/SelfLoader.html#The-__DATA__-token

-- compile-time eval() is not bound to the "program" environment, but to the "compiler" environment instead
    see README-perlito5-js near "Compile-time / Run-time interleaving"

    my $v;
    BEGIN { $v = "123" }
    use Module $v;  # $v is not accessible at compile-time

-- parse the regexes
    create an AST for regexes

-- prototypes (signatures)
    http://perldoc.perl.org/perlsub.html#Prototypes

    check that undeclared barewords give the right error
    *foo = sub () { ... }   # does prototype work here?
    check signature in sort()
    fix the prototype for 'stat(*)' (see t/test.pl in the perl test suite)

-- add "print", "printf", "say" special parsing - note this is related to indirect object notation

    indirect object notation
    http://lwn.net/Articles/451486/
    http://www.modernperlbooks.com/mt/2009/08/the-problems-with-indirect-object-notation.html
    http://shadow.cat/blog/matt-s-trout/indirect-but-still-fatal/
    http://perlbuzz.com/mechanix/2008/02/the-perils-of-perl-5s-indirect.html

    method Module $param;
    new Class( arg => $value );
    new Class::($args);
    say $config->{output} "This is a diagnostic message!";  # indirect call
    say {$config->{output}} "This is a diagnostic message!"; # say to filehandle

    use Class;
    sub Class {
    warn 'Called Class sub not Class package';
    'Class'
    }
    my $q = Class->new; # calls the Class sub above
    my $s = new Class; # throws a 'Bareword found where operator expected' error
    my $t = Class::->new # this works
    my $u = new Class::; # this also works (even with sub main in the current package)

-- "namespace" parsing
    tests: t5/01-perlito/26-syntax-namespace.t

    $ perl -e ' { package X; sub print { CORE::print(">$_[1]<\n") } } my $x = bless {}, "X"; print $x "xxx" '
    Not a GLOB reference at -e line 1.

    $ perl -e ' { package X; sub printx { CORE::print(">$_[1]<\n") } } my $x = bless {}, "X"; printx $x "xxx" '
    >xxx<

    $ perl -MO=Deparse -e ' print X:: "xxx" '
    print X 'xxx';

    $ perl -e ' use strict; my $x = X::; print $x '
    X

    $ perl -e ' use strict; my $x = X; print $x '
    Bareword "X" not allowed while "strict subs" in use 

    $ perl perlito5.pl -MO=Deparse -e ' ::X::x::y '
    join("", ::{'main::X::'} x main::y);

    $ perl -MO=Deparse -e ' ::X '
    '???';

    $ perl -MO=Deparse -e ' sub X {} ::X '
    sub X { }
    X;

    $ perl -e ' $::X::::X = 3; print $main::X::::X '        # 3
    $ perl -e ' $::X::::X = 3; print $main::main::X::::X '  # 3
    $ perl -e ' $::X::::X = 3; print $main::X::main::X '    # empty
    $ perl -e ' $::X::::X = 3; print $main::X::X '          # empty
    $ perl -e ' $::X::::X = 3; print $::::X::::X '          # empty


-- strict and warnings: create options like 'subs', 'refs'

-- clean up:
    the several "end_tables" in Expression.pm are duplicating the function of 
    $Precedence in Precedence.pm - Expression.pm should use $Precedence directly.

-- things that work in perlito5, but which are errors in 'perl'

    quotes vs. hash lookups:
    
        $ perl -e '  q}} '
        # ok
    
        $ perl -e ' $x{ q}} } '
        Unmatched right curly bracket at -e line 1, at end of line
    
        $ perl -e ' $x{ q]] } '
        # ok
    
    string interpolation with nested quotes of the same type:
    
        $ perl -e ' " $x{"x"} " '
        String found where operator expected at -e line 1, near "x"} ""

-- add tests for fixed bugs:

    add tests for signatures: "empty" _ $ ;$

    ---
    add test for "sub _" should be in package "main"
    $ perl -MO=Deparse -e ' package X; sub _ { 123 } '
    package X;
    sub main::_ {
        123;
    }

    ---
    add test for defined-or vs. m//  (2012/9/25 Конрад Боровски <notifications@github.com>)
    Note: fixed; see test t5/01-perlito/25-syntax-defined-or.t

    $ perl perlito5.pl -Isrc5/lib -Cast-perl5 -e ' shift // 2 '
    Number or Bareword found where operator expected

    $ perl perlito5.pl -Isrc5/lib -Cast-perl5 -e ' shift / 2 '
    Can't find string terminator '/' anywhere before EOF

    ---
    add test for filetest operators special case:
    ' -f($file).".bak" ' should be equivalent to -f "$file.bak"
    parses as -(f($file)).".bak" 
    but: ' -f ($file).".bak" '
    parses correctly
    This seems to be because there is a rule that \w followed by '(' is a function call;
    this needs more testing: ' ... and(2) '
    Test: redefine 'and', 'not' and check what works.

    '  $s111++ + $s222 '
    parses as  (+$s222)++

    '  $step++ < $steps '
    Can't find string terminator '>' anywhere before EOF



* Perl5 backend

-- "given" statement not implemented
-- "default" statement not implemented

-- check that \(@a) and \@a have different meanings

-- ${^NAME} needs curly-escaping

- fix regex delimiters, or escape the regexes 

-- continue block in block: ' { print 1 } continue { print 2 } '

-- emitter bug: significant parenthesis: 
    t5/01-perlito/12-context.t fails because:
    " return (4, 5) " instead of " return 4, 5 "

-- bug: ' $$x [$y] '
    emits as ${$x}->[$y];


* Javascript backend

-- check that \(@a) and \@a have different meanings

-- delete() in the middle of an array turns exists() off:

    $ perl -e ' @a = (3..7); delete $a[2]; print "exists ", (exists $a[$_] ? 1 : 0), "\n" for 0 .. $#a '
    exists 1
    exists 1
    exists 0
    exists 1
    exists 1

-- "or" has SCALAR context (Abigail++):
    See: t5/01-perlito/23-eval.t

-- "~~" operator not implemented; See also "when" implementation

-- "given" statement not implemented
-- "when" should use a "break" exception inside "given", and a "next" exception inside "for".
-- "default" statement not implemented

-- bug: some declarations are not "seen":
   for ( my $i = 0; $i < 10 ; $i++ ) { print "$i\n" }   # compiles to global $i

-- bug: don't emit throw() in term position; javascript requires a function() wrapper because throw() is a statement

-- javascript errors don't show in the global error handler when running in node.js

-- "autoload" the compiler if eval-string is used (eval-string needs the compiler at run-time)

-- symbol variables like $] ${"main::\$"} $#_
-- check that @_, $_, $a, $b and other special variables are in the right context (lexical, global, package global)

-- emit array/hash slices: @a[@x], @a{@x}

-- add alternate mro's
-- cache the mro

-- add regex compiler
-- /e modifier
-- /x modifier
-- support all perl5 regex syntax
-- @v = /x/g

-- bug: variable redeclaration does not work
-- javascript "var" erases the outer value within the whole current lexical scope
-- bug: "my" variables - this doesn't work as expected: my $v = $v
   possible fix: rename variables

-- lvalue ternary: ($a_or_b ? $a : $b) = $c;
-- lvalue substr()
-- 4-arguments substr()
-- pos($str)
-- lvalue chomp(), chop()

-- missing some types of subroutine signatures

-- bug: variable aliases create copies instead

-- generate more compact code; maybe use more subroutines instead of inlining;
   autovivification is probably the most verbose part of the code.

-- in the browser: implement "use" with XMLHttpRequest (what are the security implications?)

-- add symbol tables for scalar, array and hash
-- references to typeglobs:
    $ perl -e ' print ref(\*main) '
    GLOB
-- aliasing between lexicals and globals
    $ perl -e 'use strict; my $x = 3; *main::z = \$x; print $main::z; '
    3

-- string increment and string ranges
    See: p5str_inc()

-- finish "overload" implementation

-- pack(), unpack()
-- y()()

-- BEGIN{} should execute in the environment of the program under compilation
-- BEGIN/END that are defined inside blocks/closures need to run inside some pseudo-environment
    even if the closure was never created or used in the first place

-- bug - method call context is disabled, because it breaks bootstrap.
    in Runtime.pm:
    function p5call(invocant, method, list, p5want) {
        list.unshift(invocant);
        p5want = 0;  // TODO BUG - workaround for broken bootstrap


* Nice to Have

-- debugging symbols
-- line numbers in error messages

-- caller()
-- "when"

-- run more of the "perl" test suite

-- proper "use strict" and "use warnings"
-- use the same error messages and warnings as 'perl'
-- no warnings 'redefine';

-- __LINE__, __FILE__

-- INIT{}, END{}
   look at the implementation in perlito6-in-Go

-- source code - remove Perl 6 code such as "token"
   (fixed: This is only loaded if the grammar compiler is needed)

-- *{ $name }{CODE}->();

-- local(*{$caller."::a"}) = \my $a;
-- *{$pkg . "::foo"} = \&bar;



* Deprecate

-- remove unused features from src5/lib/Perlito5/Grammar/Regex.pm

-- Interpreter backend
   this is not being maintained; the code is still in src5/lib/Perlito5/Eval.pm just in case

-- Perl6 backend (started)
   this is not being maintained; not sure if compiling to Perl6 is the best way
   maybe compiling directly to Parrot/dotnet/Haskell gives better results