如何使用STD.pm6语法解析Perl6代码？

Question

我想要使用STD.pm6从Perl6解析Perl6代码的最小工作示例

运行像这样的东西

use v6;
use STD.pm6;
my $j = slurp 'e:\src\perl6\valid-p6-script.p6';
my $o = STD::Grammar.parse($j);
say $o.perl;

under debugger给了我非常奇怪的输出：

e:\src\prg\perl6>c:\rakudo\bin\perl6-debug-m.bat -I. p6.p6
>>> LOADING p6.p6
>>> LOADING E:\src\prg\perl6\STD.pm6
Unhandled exception: ctxlexpad needs an MVMContext
   at gen/moar/m-CORE.setting:15136  (C:\rakudo/share/perl6/runtime/CORE.setting.moarvm::24)
 from gen/moar/m-CORE.setting:15250  (C:\rakudo/share/perl6/runtime/CORE.setting.moarvm:AT-KEY:95)
 from gen/moar/m-CORE.setting:4291  (C:\rakudo/share/perl6/runtime/CORE.setting.moarvm:postcircumfix:<{ }>:4294967295)
 from C:\rakudo/share/perl6/lib/Debugger/UI/CommandLine.pm:736  (C:\rakudo\share\perl6\lib\Debugger\UI\CommandLine.pm.mo
arvm::82)
 from gen/moar/m-CORE.setting:2826  (C:\rakudo/share/perl6/runtime/CORE.setting.moarvm:sink-all:168)
 from gen/moar/m-CORE.setting:10187  (C:\rakudo/share/perl6/runtime/CORE.setting.moarvm:sink:36)
 from C:\rakudo/share/perl6/lib/Debugger/UI/CommandLine.pm:730  (C:\rakudo\share\perl6\lib\Debugger\UI\CommandLine.pm.mo
arvm:unhandled:114)
 from C:\rakudo/share/perl6/lib/Debugger/UI/CommandLine.pm:721  (C:\rakudo\share\perl6\lib\Debugger\UI\CommandLine.pm.mo
arvm::25)
 from gen/moar/m-Metamodel.nqp:3586  (C:\rakudo\share\nqp\lib/Perl6/Metamodel.moarvm:enter:28)
 from gen/moar/m-CORE.setting:5190  (C:\rakudo/share/perl6/runtime/CORE.setting.moarvm:CALL-ME:57)
 from gen/moar/m-BOOTSTRAP.nqp:2749  (C:\rakudo/share/nqp/lib/Perl6/BOOTSTRAP.moarvm::93)
 from gen\moar\stage2\NQPHLL.nqp:1425  (C:\rakudo\share\nqp\lib/NQPHLL.moarvm:command_eval:380)
 from src/Perl6/Compiler.nqp:59  (C:\rakudo\share\nqp\lib/Perl6/Compiler.moarvm:command_eval:93)
 from gen\moar\stage2\NQPHLL.nqp:1365  (C:\rakudo\share\nqp\lib/NQPHLL.moarvm:command_line:114)
 from gen/moar/m-perl6-debug.nqp:497  (C:\rakudo\share\perl6\runtime\perl6-debug.moarvm:MAIN:190)
 from gen/moar/m-perl6-debug.nqp:440  (C:\rakudo\share\perl6\runtime\perl6-debug.moarvm:<mainline>:68)
 from <unknown>:1  (C:\rakudo\share\perl6\runtime\perl6-debug.moarvm:<main>:8)
 from <unknown>:1  (C:\rakudo\share\perl6\runtime\perl6-debug.moarvm:<entry>:9)

或者不使用调试器：

e:\src\prg\perl6>c:\rakudo\bin\perl6.bat -I. p6.p6
===SORRY!=== Error while compiling E:\src\prg\perl6\STD.pm6
Semicolon form of 'grammar' without 'unit' is illegal.  You probably want to use 'unit grammar'
at E:\src\prg\perl6\STD.pm6:8
------> :ver<6.0.0.alpha>:auth<http://perl.org>;<HERE><EOL>
  from p6.p6:2

Answer 1

STD.pm6是Larry在开发各种Perl6编译器(Rakudo、Pugs、Niecza等)期间维护的参考语法/验证器。它附带了一个名为viv的专用工具，可以将它翻译成Perl5，据我所知，它从未在任何主流编译器上运行过。

随着6.c语言的发布，引用实现的火炬基本上传递给了Rakudo，后者使用用NQP编写的its own grammar来解析Perl6。

虽然这个语法(与corresponding actions结合)可以通过导入这些模块:from<NQP>来用于手动解析，但更友好的方法(例如，不需要声明$*LINEPOSCACHE)将通过相应的编译器对象：

say nqp::getcomp('perl6').eval($source, :target<parse>).dump;

其他感兴趣的目标可能是:target<syntaxcheck>以及更低级的:target<ast>，或者对于好奇的人来说，甚至可能是:target<mast>。

Answer 2

#perl6对话中的工作示例：

use nqp; 
use Perl6::Grammar:from<NQP>; 
use Perl6::Actions:from<NQP>; 
my $source = q|say "hello world";|; 
my $*LINEPOSCACHE; 
my $p6c = Perl6::Grammar.parse($source, :actions(Perl6::Actions.new())); 
say $p6c.dump