Tree Top
30
TreeTop (uy version) ++[>++[>++[>++[>++<-] <-] <-] <-] >>>><+++++[>+ +++++++++<-] >. <+++[>++++++<-] >+. <+++++++[>+ +<-] >. <+[>-<-] >-. <+++ [>---------------------------<-] >. <+++++++++++ ++++++++++++++++++++++++++++++[>++<-] >. <+++ [>--<-] >. <+++++++[>++<-] >. <+++++++++++++ [>------<-] >. <+++[>----<-] >. <+++++++++++++++ ++++++++++++++++++++++++++[>++<-] >+. <++[>--<-] >. <+++++++++++++[>------<-] >-. <+++++++[>+++++ +++++++<-] >. <+++[>----<-] >. <++[>++++++++<-] >. <+++++++++++[>--------<-] >. <+++++++[>++++++ ++++<-] >. <+++[>+++<-] >. <++[>+<-] >+. <++++++ +++++++++++++++++++++++++++++++++++[>--<-] >. <+ ++++++++++[>++++++<-] >+. <+++[>++++<-] >. <+[>- <-] >-. <+[>+<-] >.
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Tree Top at RubyConfUy
Transcript of Tree Top
TreeTop (uy version)TreeTop (uy version)
++[>++[>++[>++[>++<-] <-] <-] <-] >>>><+++++[>++++++++++<-] >. <+++[>++++++<-] >+.
<+++++++[>++<-] >. <+[>-<-] >-. <+++[>---------------------------<-] >. <+++++++++++++++++++++++++++++++++++++++++[>++<-] >. <+++[>--<-] >. <+++++++[>++<-] >. <+++++++++++++[>------<-] >. <+++[>----<-] >. <+++++++++++
++++++++++++++++++++++++++++++[>++<-] >+. <++[>--<-] >. <+++++++++++++[>------<-] >-. <+++++++[>++++++++++++<-] >. <+++[>----<-] >. <++[>++++++++<-] >. <++++++++++
+[>--------<-] >. <+++++++[>++++++++++<-] >. <+++[>+++<-] >. <++[>+<-] >+. <+++++++++++++++++++++++++++++++++++++++++[>--<-] >. <+++++++++++[>++++++<-] >+. <+++
[>++++<-] >. <+[>-<-] >-. <+[>+<-] >.
++[>++[>++[>++[>++<-] <-] <-] <-] >>>><+++++[>++++++++++<-] >. <+++[>++++++<-] >+.
<+++++++[>++<-] >. <+[>-<-] >-. <+++[>---------------------------<-] >. <+++++++++++++++++++++++++++++++++++++++++[>++<-] >. <+++[>--<-] >. <+++++++[>++<-] >. <+++++++++++++[>------<-] >. <+++[>----<-] >. <+++++++++++
++++++++++++++++++++++++++++++[>++<-] >+. <++[>--<-] >. <+++++++++++++[>------<-] >-. <+++++++[>++++++++++++<-] >. <+++[>----<-] >. <++[>++++++++<-] >. <++++++++++
+[>--------<-] >. <+++++++[>++++++++++<-] >. <+++[>+++<-] >. <++[>+<-] >+. <+++++++++++++++++++++++++++++++++++++++++[>--<-] >. <+++++++++++[>++++++<-] >+. <+++
[>++++<-] >. <+[>-<-] >-. <+[>+<-] >.
The gloryThe glory
DSL (embedded)DSL (embedded)
Domain.specific do result.should be 2end
L?L?
In order to write a languageAs a Ruby programmer
I want to have an easy and powerful tool
Write a lang? WTF?Write a lang? WTF?
In fact, you do it all the time.Open files, parse stuff, turn it into strings,
numbers, arrays and link it to code.Like when you wrote your first csv parser.
(yeah, i know you did it...)
You just didn’t had the right tool.
BrainFuckBrainFuck
3000 slots
00 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
><+-.,[]
00 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
>00 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
<00 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
+11 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
-00 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
,00 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
,00 00 00 00 00 00 00 00 00
BB
BrainFuckBrainFuck
,6666 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
.6666 00 00 00 00 00 00 00 00
BB
BrainFuckBrainFuck
[]6666 00 00 00 00 00 00 00 00
BrainFuckBrainFuck
[>+]6666 11 11 11 11 11 11 11 11
(now some live coding...)
CFGCFGFormally defined by Noam
Chomsky in the 50s.(Yeah, that weird talking guy from the World Social Forum.
For your info he is a great linguist.)
LEX, Yacc
Idea: Generates a language
CFGCFG
‘if(‘ exp ‘)’ stmt ‘else’ stmt | ‘if(’ exp ‘)’ stmt
oror
CFGCFG
// Wich alert will be executed?
if(false) if(false) alert(“Don’t say ‘the second if alert’.”)else alert(“Say ‘the else alert’. Say it!!!”)
CFGCFGGotcha!!!
None.=> undefined
Generally, languages prefer to associate else to the nearest if. But this has to be made in a “meta” rule.
TreetopTreetop
treetop.rubyforge.orgrubyconf2007.confreaks.com/d1t1p5_treetop.html
Nathan Sobo (Pivotal Labs), Clifford Heath, Nick Kallen & more.
PEGPEGParsing Expression Grammars
Brian Ford paper 2004: http://pdos.csail.mit.edu/~baford/packrat/
Priorities, Not Ambiguities / (slash operator)
(a / a b) is different of (a b / a)Syntactic Predicates (& and !)
Regular Expression LikeNo left recursion.
Idea: Recognizes a language
PEGPEG
Result:- linear time parsing using memoization- one and only one valid parse tree- no dangling else cases- much easier to learn and useDrawbacks- still new- memory eater- not suitable for natural language processing
PEGPEG
‘if(‘ exp ‘)’ stmt ‘else’ stmt / ‘if(’ exp ‘)’ stmt
priority operatorpriority operator
ProjectsProjectsarithmetic + lambda calculus + sql
gherkin (cucumber)
mail (rails 3 standard)
0xCOFFEE (full lang compiled to LLVM)many more
html, css, json, odp, scheme, apache conf, trxl, lolcode, brainfuck,sloc, hairball (haml), vcard, hapag, dcf, lordbishop (names)
BeyondBeyond
Compile with LLVM(look at 0xCOFFEE)
Compile to Parrot?Implement Ruby?
Watch Citrus
Other langsOther langs
Rats! JavaPetitParser SmallTalk
ppeg, pyPEG, pyparsing PythonPerl6 rules Perl6 (native!)
Frisby, Leafy Haskell
CSV by the wayCSV by the way
grammar Csv rule file (line [\n])* line end rule line (value ',')* value end rule value [^,]+ endend
+++[>+++[>+++++++<-] <-] >><+++[>++++++<-] >. <+++[>++++++++++++<-] >. <++[>--------<-] >. <+++++
++[>++<-] >. <+[>+<-] >. <+++++[>--<-] >-. <+++[>++<-] >. <+[>-<-] >. <++[>++<-] >+. <+++++++++++++
[>----<-] >.
@joaomilho . mailee.merailer.im/chuck-norris
