Developing a Language

Developinga

Language

Evan Phoenix Feb 5th, 2011

★ @evanphx github.com/evanphx

Tuesday, February 8, 2011

#11Tuesday, February 8, 2011

LA.RBLos Angeles Ruby Brigade

Tuesday Night. Every Week.http://rb.la


http://rb.la

http://rb.la

DINNER


DINNERTuesday, February 8, 2011

Which came first?


Language > Idea


Language < Idea


Language = Idea


The programmer, like the poet,

works only slightly removed

from pure thought-stuff.

- Fred Brooks


If ideas are a manifestation of

language


Can better language lead to

better ideas?


better!=

newer


��


To craft a language from

scratch is to take 95% from the

past and call it groundbreaking.

- Evan Phoenix


Peek back


RLK


Implement with ease

RLK


KPeg

RLK


KPeg

A new parsing library

RLK


Prattle < RLK


github.com/evanphx/prattle.git

github.com/evanphx/kpeg.git

URLs

git://192.168.2.88/prattle

In the Building

In the Cloud


Dude. Really?


Prattle


selftruefalsenil


+module Prattle+ module AST+ class Self < AST::Node+ Prattle::Parser.register self++ def self.rule_name+ "self"+ end++ def initialize+ # Nothing.+ end++ def self.grammar(g)+ g.self = g.str("self") { Self.new }+ end+ end+ end+end


def self.grammar(g) g.self = g.str("self") { Self.new }end

047b522

Self


def self.grammar(g) g.true = g.str("true") { True.new }end

04ad51b

True


def self.grammar(g) g.false = g.str("false") { False.new }end

04ad51b

False


def self.grammar(g) g.nil = g.str("nil") { Nil.new }end

7609e64

Nil


01042

10323

Number


def self.grammar(g) g.number = g.reg(/0|([1-9][0-9]*)/) { |i| Number.new(i.to_i) }end

a06d98c

Number


def self.grammar(g) g.root = g.any(:true, :false, :self, :nil, :number) end

dfd78cb

Root


root = self | true | false | nil | number


REPL


Instant Gratification

REPL


$ rbx bin/repl.rb> 42#<Prattle::AST::Number:0x9c @value=42>> true#<Prattle::AST::True:0x9d>


def bytecode(g) g.push :selfend

4e4c1c9

Self


def bytecode(g) g.push :trueend

4e4c1c9

True


def bytecode(g) g.push :falseend

4e4c1c9

False


def bytecode(g) g.push :nilend

4e4c1c9

Nil


def bytecode(g) g.push @valueend

4e4c1c9

Number


def self.grammar(g) not_quote = g.many( g.any(escapes, /[^']/)) { |*a| a.join } g.string = g.seq("'", g.t(not_quote), "'") { |str| String.new(str) }end

String


char = escapes | [^’]not_quote = char* string = “‘“ not_quote “‘“

String


$ rbx bin/repl.rb> 42=> 42> true=> 42> ‘hello’=> “hello”


BORING


Unary Send

3 class


Unary Send

3.classRuby


Unary Send

3 class


g.seq(:number, “ “, :method_name) { |v,_,n| UnarySend.new(v,n) }

Unary Send


us = number “ “ method_name

Unary Send


Unary Send

true class


g.seq(:atom, “ “, :method_name) { |v,_,n| UnarySend.new(v,n) }

Unary Send


us = atom “ “ method_name

Unary Send


Unary Send

3 class class


g.any(g.seq(:unary_send, “ “, :method_name) { |v,_,n| UnarySend.new(v,n) },g.seq(:atom, “ “, :method_name) { |v,_,n| UnarySend.new(v,n) })

Unary Send


us = us “ “ method_name | atom “ “ method_name

Unary Send


def bytecode(g) @receiver.bytecode(g) g.send @method_name.to_sym, 0end

Unary Send


$ rbx bin/repl.rb> 3 class=> Fixnum> 3 class class=> Class> ‘hello’ class=> String


‘hello’ index: ‘o’

Keyword Send


“hello”.index(“o”)

Keyword Send

Ruby


g.keyword_send = g.seq(:atom, ‘ ‘, :method_name, “:”, “ “, :atom)

Keyword Send


ks = atom “ “ method_name “: ” :atom

Keyword Send


‘hello’ at: 0 put: ‘j’

Keyword Send


“hello”[0] = “j”

Keyword Send

Ruby


g.pairs = g.seq(:method_name, “:”, “ “, :atom)

Keyword Send


g.keyword_send = g.seq( :atom, ‘ ‘, g.many([:pair, ‘ ‘]), :pair )

Keyword Send


ks = atom (pair ‘ ‘)+ pair

Keyword Send


def bytecode(g) @receiver.bytecode(g) @arguments.each do |a| a.bytecode(a) end g.send @method_name.to_sym, @arguments.sizeend

Keyword Send


$ rbx bin/repl.rb> ‘hello’ index: ‘o’

NoMethodError: Unknown method ‘index:’


‘hello’ index: ‘o’

Keyword Send


“hello”.send( “index:”, “o” )

Keyword Send

Ruby


‘hello’ ~index: ‘o’

Keyword Send


def bytecode(g) if @method_name[0] == ?~ ruby_style else smalltalk_style endend

Keyword Send


“hello”.send( “index”, “o” )

Keyword Send

Ruby


$ rbx bin/repl.rb> ‘hello’ ~index: ‘o’=> 4NoMethodError: Unknown method ‘index:’


obj string at: 0 put: ‘j’

Keyword Send


g.keyword_send = g.seq( :atom, ‘ ‘, g.many([:pair, ‘ ‘]), :pair )

Keyword Send


ks = atom (pair ‘ ‘)+ pair

Keyword Send


g.any(:atom, :unary_send)

Keyword Send


recv = us | atom ks = recv (pair ‘ ‘)+ pair

Keyword Send


[ 1 ]Block


g.block = g.seq(‘[‘, :expr, ‘]’)

Keyword Send


expr = ks | us | atom

Keyword Send


block = “[“ expr “]

Keyword Send


[ 1. 2 ]Block


g.exprs = g.seq(:expr, g.kleene(‘.’, :expr))

Keyword Send


exprs = (‘.’ expr)*

Keyword Send


block = “[“ exprs “]

Keyword Send


$ rbx bin/repl.rb> 10 ~times: [ Kernel ~puts: ‘hello’ ]


$ rbx bin/repl.rb> 10 ~times: [ Kernel ~puts: ‘rb.la’ ]“rb.la”“rb.la”“rb.la”...=> 10


$ rbx bin/repl.rb> 10 ~times: [ :x | Kernel ~p: x ]


$ rbx bin/repl.rb> 10 ~times: [ :x | Kernel ~p: x ]012...=> 10


ary concat: a; concat: b; concat: c

Cascade Send


3 + 4 * 5

Operators


$ rbx bin/repl.rb> 3 + 4 * 5


$ rbx bin/repl.rb> 3 + 4 * 5=> 35


parens = “(“ expr “)

Parens


$ rbx bin/repl.rb> 3 + (4 * 5)=> 23


zero to usable


BIG IDEA


little idea


ComplexLanguage


simple language


See ya out there.

Thanks!


MIA: Return


MIA: =


Developing a Language

Technology

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