Parrot Allison Randal The Perl Foundation & O'Reilly Media, - - PowerPoint PPT Presentation

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Parrot Allison Randal The Perl Foundation & O'Reilly Media, - - PowerPoint PPT Presentation

May 12, 2023 233 likes •839 views

Parrot Allison Randal The Perl Foundation & O'Reilly Media, Inc. There's an odd misconception in the computing world that writing compilers is hard. This view is fueled by the fact that we don't write compilers very often. People used to

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Parrot

Allison Randal The Perl Foundation & O'Reilly Media, Inc.

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There's an odd misconception in the computing world that writing compilers is hard. This view is fueled by the fact that we don't write compilers very often. People used to think writing CGI code was hard. Well, it is hard, if you do it in C without any tools.

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Parrot VM

Ruby Python Perl 5 Perl 6 PHP

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Parrot VM

Dylan Forth Tcl Ruby Scheme Python Perl 5 TeX macro Perl 6 PHP Objective-C Lua Javascript Invent your language here.

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Dynamic Languages

  • Runtime vs. compile-time
  • Extend code (eval, load)
  • Define classes
  • Alter type system
  • Higher-order functions
  • Closures, Continuations, Coroutines
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Why?

  • Revolution
  • Powerful tools
  • Portability
  • Interoperability
  • Drive innovation
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Register-based

  • Stack operations
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Register-based

  • Stack operations

14

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Register-based

  • Stack operations

9 14

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Register-based

  • Stack operations

9 14 add

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Register-based

  • Stack operations

23

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Register-based

  • Stack operations
  • Register operations

9 14

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Register-based

  • Stack operations
  • Register operations

9 14 add

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Register-based

  • Stack operations
  • Register operations

9 14 23

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Register-based

  • Stack operations
  • Register operations
  • Fewer instructions
  • Hardware registers
  • Register spilling
  • Flexible register sets
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Continuation Passing Style

  • Stack-based control flow
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Continuation Passing Style

  • Stack-based control flow

foo

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Continuation Passing Style

  • Stack-based control flow

return addr foo

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Continuation Passing Style

  • Stack-based control flow

9 return addr foo 12

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Continuation Passing Style

  • Stack-based control flow

return addr

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Continuation Passing Style

  • Stack-based control flow
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Continuation Passing Style

  • Stack-based control flow
  • Continuation-based

control flow

Context: main

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Continuation Passing Style

  • Stack-based control flow
  • Continuation-based

control flow

Context: main Context: foo

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Continuation Passing Style

  • Stack-based control flow
  • Continuation-based

control flow

Continuation Context: main Context: foo

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Continuation Passing Style

  • Stack-based control flow
  • Continuation-based

control flow

Continuation Context: main Context: foo Context: bar

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Continuation

Continuation Passing Style

  • Stack-based control flow
  • Continuation-based

control flow

Continuation Context: main Context: foo Context: bar

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Continuation

Continuation Passing Style

  • Stack-based control flow
  • Continuation-based

control flow

  • Deeply nested contexts
  • Tail recursion

Continuation Context: main Context: foo Context: bar

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Parrot VM

PASM (assembly language) Parser Grammar Engine (PGE) Parrot Compiler Toolkit (PCT)

I/O GC Events Threads OO Unicode Exceptions IMCC STM JIT

PIR (intermediate representation)

NQP PAST HLLCompiler

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PASM

  • Assembly language
  • Simple syntax
  • add I0, I1, I2
  • Human-readable bytecode
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PIR

  • Syntactic sugar
  • $I0 = $I1 + $I2
  • Named variables
  • .local int myvar
  • $I0 = myvar + 5
  • Sub and method calls
  • result = object.'method'($I0)
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NQP

  • Not Quite P(erl|ython|HP|uby)
  • Lightweight language
  • $a := 1;
  • print($a, "\n");
  • Compiler tools
  • $past := PAST::Op.new( :name('printnl') );
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Parser Grammar Engine

  • Regular expressions
  • Recursive descent
  • Operator precedence parser
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HLLCompiler

  • Base library
  • Quick start
  • Common features
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Pynie

  • Download
  • http://www.parrotcode.org
  • Build
  • $ perl Configure.PL
  • $ make test
  • Language
  • $ cd languages/pynie
  • $ make test
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Pynie

  • hello.py
  • print "Hello, World!"
  • Run
  • $ parrot pynie.pir hello.py
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pynie.pir

  • 67 lines
  • Half documentation
  • c = hllcompiler.new()
  • c.language('Pynie')
  • c.parsegrammar('Pynie::Grammar')

c.parseactions('Pynie::Grammar::Actions')

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Grammar.pg

  • Parser
  • token stmt_list {
  • <simple_stmt> [ ';' <simple_stmt> ]* ';'?
  • {*}
  • }
  • Familiar?
  • stmt_list ::=
  • simple_stmt (";" simple_stmt)* [";"]
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Actions.pct

  • Transform to AST
  • method identifier($/) {
  • make PAST::Var.new( :name( ~$/ ),
  • :scope('package'),
  • :node($/)
  • );
  • }
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Value Transformation

42

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Value Transformation

42 \d+ Parser grammar rule “integer” token integer { \d+ }

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Value Transformation

42 \d+ Parser grammar rule “integer” <integer> value: 42 Parse tree

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Value Transformation

42 \d+ Parser grammar rule “integer” <integer> value: 42 Parse tree integer Transform rule

method integer($/) {...}

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Value Transformation

42 \d+ Parser grammar rule “integer” <integer> value: 42 Parse tree integer Transform rule <PAST::Val> value: 42 returns: Integer AST node

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Value Transformation

42 \d+ Parser grammar rule “integer” <integer> value: 42 Parse tree integer AST tree grammar rule AST node PAST::Val Transform rule

  • st = self.as_post(ast)

<PAST::Val> value: 42 returns: Integer

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Value Transformation

42 \d+ Parser grammar rule “integer” <integer> value: 42 Parse tree integer Transform rule <PAST::Val> value: 42 returns: Integer AST node PAST::Val Transform rule <POST::Op> result: 1 OST node

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Value Transformation

42 \d+ Parser grammar rule “integer” <integer> value: 42 Parse tree integer Transform rule <PAST::Val> value: 42 returns: Integer AST node PAST::Val Transform rule <POST::Op> result: 1 OST node POST::Val Transform rule

self.pir(ost)

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Value Transformation

42 \d+ Parser grammar rule “integer” <integer> value: 42 Parse tree integer Transform rule <PAST::Val> value: 42 returns: Integer AST node PAST::Val Transform rule <POST::Op> result: 1 OST node POST::Val 42 Transform rule

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Operator Transformation

6 * 9

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Operator Transformation

6 * 9 infix:* Parser grammar OPP rule

proto infix:* is looser(prefix:+) {...}

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Operator Transformation

6 * 9 infix:* Parser grammar OPP rule <expr> type: 'infix:*' Parse tree <integer> value: 6 <integer> value: 9

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Operator Transformation

<expr> type: 'infix:*' Parse tree <integer> value: 6 <integer> value: 9

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Operator Transformation

<expr> type: 'infix:*' Parse tree expr Transform rule <integer> value: 6 <integer> value: 9

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Operator Transformation

<expr> type: 'infix:*' Parse tree expr Transform rule <integer> value: 6 <integer> value: 9 AST tree <PAST::Op> name: infix:* <PAST::Val> value: 6 returns: Integer <PAST::Val> value: 9 returns: Integer

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Operator Transformation

AST tree <PAST::Op> name: infix:* <PAST::Val> value: 6 returns: Integer <PAST::Val> value: 9 returns: Integer

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Operator Transformation

PAST::Op Transform rule AST tree <PAST::Op> name: infix:* <PAST::Val> value: 6 returns: Integer <PAST::Val> value: 9 returns: Integer

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Operator Transformation

PAST::Op Transform rule AST tree <PAST::Op> name: infix:* <PAST::Val> value: 6 returns: Integer <PAST::Val> value: 9 returns: Integer OST tree <POST::Ops> <POST::Ops> result: 6 <POST::Ops> result: 9 <POST::Op> name: n_mul variable setup <POST::Ops> result: $P1

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Operator Transformation

  • .sub _main :main
  • new $P1, 'Integer'
  • new $P2, 'Integer'
  • set $P2, 6
  • new $P3, 'Integer'
  • set $P3, 9
  • mul $P1, $P2, $P3
  • .end
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Examples

  • In the Parrot distribution:
  • examples/tutorial/*.pir
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Questions?

  • Further Reading

– “Continuations and advanced flow control”

by Jonathan Bartlett

<http://www.ibm.com/developerworks/linux/library/l- advflow.html>

– “The case for virtual register machines” by

Brian Davis, et al.

<http://portal.acm.org/citation.cfm?id=858575>