Making Ruby? - ゆるふわRuby生活 - Nobuyoshi Nakada

Self-introduction
Fulltime Ruby Committer @
Salesforce.com / Heroku
(2011~)
So called Matz team
Matz
Nobu
Ko1

日常/Daily
デバッグ/Debugging
新機能/New features
バグ/Bug making
家事・育児/Housekeeping etc

About Ruby development
Repository
Issues
Developers’ meeting

Repository
Subversion
svn+ssh://svn@ci.ruby-lang.org/ruby
https://svn.ruby-lang.org/cgi-bin/viewvc.cgi/
Git mirror
https://github.com/ruby/ruby

Why not Git?
ruby is older than Git
moving to git needs some works
hash is not clear as revision
number
Windows is not supported
officially
Not enough advantage

Issues
Redmine
https://bugs.ruby-lang.org/projects/ruby-trunk/issues
Mailing List
ruby-core@ruby-lang.org (en)
ruby-dev@ruby-lang.org (ja)

Developers’ meeting
Once per month
In Tokyo (usually)
in Kyoto 2016/9
Taking inventory of bug tickets

How to build Ruby (from tarball)
Similar to other OSS
configure
+
make

Out-of-Place build
Various configure options
Virtual machines
Linux, Windows, …
GNU Makefile to build at once
https://github.com/nobu/build-files/blob/master/Ruby.mk

Various configure options
Many build directories by combination
--enable-shared
--with-arch
optflags
etc

How to Build Ruby (from repo)
subversion / git(mirror)
autoconf
bison
gperf
ruby

Ruby
BASERUBY
pre-installed ruby
MINIRUBY
ruby made during the build

BASERUBY
Ruby (maybe old) to generate source
files
parse.y → parse.c, …
defs/id.def → id.h, id.c
insns.def → vm.inc, insns.inc,
…
etc…

MINIRUBY
To generate Makefiles for extension
libraries, and others

MINIRUBY’s feature
No dynamic loading
↓
Runnable alone
No LD_LIBRARY_PATH
Convenient for debugging

MINIRUBY’s limitation
Feature can be also a limitation
Unable to load extension
libraries
b/c restriction of Windows DLL
can’t share exts with normal ruby
built-in encodings only
ASCII-8BIT, US-ASCII, UTF-8
for -K option: EUC-JP, Shift_JIS

Building encodings
To generate Makefile by erb
no details
Similar to exts but bit simpler

Building extension libraries
execute extconf.rb files under
ext and gems directories
Dir.glob("{ext,gems}/**/extconf.rb") do |file|
load(file)
end
generate dedicated Makefile
(exts.mk)

Parallel build (~2.4)
building miniruby ⇒ parallel
(w/ GNU make)
building extension libraries ⇒
parallel
each extconf.rb ⇒ sequential
⇒ making exts.mk is slow

Parallel build (2.5)
run each directories underneath
ext and gems
no dependencies each other
depends on the parent only
composite each exts.mk files
⇒ faster configuration

Problem
No headers and libraries are
installed at build
C headers provided by ruby
ruby.h, etc
library files provided by ruby
libruby.so, etc

Solution
Mimic global variables used in
mkmf.rb by trace_var
$extmk
$ruby

$trace_var Hook changes of a global variable trace_var(symbol, cmd ) trace_var(symbol) {|val| block } -> nil -> nil Controls tracing of assignments to global variables. The parameter symbol identifies the variable (as either a string name or a symbol identifier). cmd (which may be a string or a Proc object) or block is executed whenever the variable is assigned. The block or Proc object receives the variable's new value as a parameter. Also see Kernel::untrace_var. trace_var :$_, proc {|v| puts "$_ is now '#{v}'" } $_ = "hello" $_ = ' there' produces: $_ is now 'hello' $_ is now ' there'$ $extmk
Flag to handle bundled exts in mkmf.rb
set source directory from build
directory
set built extension directory
chain $ruby hook

$extmk
Flag to handle bundled exts in mkmf.rb
set source directory from build
directory
set built extension directory
chain $ruby hook

$ruby
Path to ruby to run
set up RbConfig configurations
set $ruby path

w/o local variable
# p = 2
p (-1.3).abs #=> 1.3

w/ local variable
p = 2
p (-1.3).abs #=> -1.3

Exactly Not-A-Bug
Ancient Spec
at least 1.1

Just-size bug
“Demon Castle parse.y” by mame
“Monstrous” lex_state
But not so hard

-w option
$ ruby -w -e 'p=2; p (-1.3).abs'
-e:1: warning: don't put space
before argument parentheses

$parser_yylex() the lexical analysis case '(': // ... else if (lex_state == (EXPR_END|EXPR_LABEL) && space_seen) { rb_warning0("don't put space before argument parentheses"); } // ... SET_LEX_STATE(EXPR_BEG|EXPR_LABEL);$ What’s space_seen?
a space was seen just before the
current token?
p (-1.3).abs
^------------!Here!

What’s space_seen?
a space was seen just before the
current token?
p (-1.3).abs
^------------!Here!

lex_state
state of lexer
(EXPR_END|EXPR_LABEL) …

What’s EXPR_END?
Able to end an expression
just after right paren of method
just after method name w/o paren
just after method arg w/o paren
…

What’s EXPR_LABEL?
Able to place a label
just after left paren of method
just after method name w/o paren
just after method arg w/o paren

$In parse_ident() parse an identifier starts with a lower letter (local variable / method) ident = tokenize_ident(parser, last_state); if (!IS_lex_state_for(last_state, EXPR_DOT|EXPR_FNAME) && (result == tIDENTIFIER) && /* not EXPR_FNAME, not attrasgn */ lvar_defined(ident)) { SET_LEX_STATE(EXPR_END|EXPR_LABEL); }$ What’s lvar_defined(ident)?
Prediction to tell “whether the name
referred as ident (p here) is
defined as a local variable in the
current scope”

What’s lvar_defined(ident)?
Prediction to tell “whether the name
referred as ident (p here) is
defined as a local variable in the
current scope”

Rules
W/o variable
primary
: tLPAREN_ARG
W/ variable
paren_args
: '(' opt_call_args rparen

How to Fix?
Remove the condition by lvar_defined
I consider it a bug, but…

literal symbol by intern
compile.c (iseq_compile_each0):
literal symbol should not be
affected by redefinition of
String#intern method.
vm_insnhelper.c (rb_vm_str_intern):
intern a string into a
symbol directly.

[Feature #13812]
Refinements can’t affect string
interpolation

Difference
Conversion is explicitly visible or
not

New Features
No eye-catcher in 2.5
Such as &. in 2.3
“Unicode case” in 2.4

Approved
rescue inside do/end
Array#append, prepend
Hash#transform_keys
Kernel#yield_self
…

Rejected
neko ^..^ operator (in Perl6)
User-defined operator

Under Discussion
Method extraction operator
Kernel#method -> Method instance
Rightward assignment

Write Ruby
Wouldn’t you write New Ruby?
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