Ruby has own trinary operator (conditional operator)
p true ? 1 : 2 #=> 1
p false ? 1 : 2 #=> 2
Let's make a something like it by Ruby.
class TrueClass
def _?(&b)
Trinary.new(b)
end
end
class FalseClass
def _?(&b)
Trinary.new(nil)
end
end
class Trinary
def initialize(x)
@x = x
end
def _(&y)
@x ? @x.call : y.call
end
end
p true._? { :a }._ { :b } #=> :a
p false._? { :a }._ { :b } #=> :b
The original idea was from nanki
I tried My First Blog Tutorial which is documented in Merb official site.
Via http://wiki.merbivore.com/installing_merb_from_edge
I'm not interested in any stable versions of software, so I decided to install edge merb.
$ git clone git://github.com/wycats/merb.git
$ cd merb
$ sudo rake install
I got messages include errors.
WARNING: description and summary are identical
mv merb-1.1.gem pkg/merb-1.1.gem
Failed to install gem '/Users/ujihisa/git/merb/merb/pkg/merb-1.1.gem (1.1)' (merb requires merb_datamapper (= 1.1, runtime))
WARNING: no rubyforge_project specified
WARNING: description and summary are identical
mv merb-core-1.1.gem pkg/merb-core-1.1.gem
Successfully installed merb-core-1.1
Writing executable wrapper /opt/local/bin/merb
WARNING: description and summary are identical
mv merb_datamapper-1.1.gem pkg/merb_datamapper-1.1.gem
Failed to install gem '/Users/ujihisa/git/merb/merb_datamapper/pkg/merb_datamapper-1.1.gem (1.1)' (merb_datamapper requires merb-actionorm (~> 1.1, runtime))
WARNING: description and summary are identical
mv merb-action-args-1.1.gem pkg/merb-action-args-1.1.gem
Successfully installed merb-action-args-1.1
WARNING: description and summary are identical
mv merb-assets-1.1.gem pkg/merb-assets-1.1.gem
Successfully installed merb-assets-1.1
WARNING: description and summary are identical
mv merb-slices-1.1.gem pkg/merb-slices-1.1.gem
Successfully installed merb-slices-1.1
Writing executable wrapper /opt/local/bin/slice
WARNING: description and summary are identical
mv merb-actionorm-1.1.gem pkg/merb-actionorm-1.1.gem
Successfully installed merb-actionorm-1.1
WARNING: description and summary are identical
mv merb-auth-core-1.1.gem pkg/merb-auth-core-1.1.gem
WARNING: description and summary are identical
mv merb-auth-more-1.1.gem pkg/merb-auth-more-1.1.gem
WARNING: description and summary are identical
mv merb-auth-slice-password-1.1.gem pkg/merb-auth-slice-password-1.1.gem
WARNING: description and summary are identical
mv merb-auth-1.1.gem pkg/merb-auth-1.1.gem
Successfully installed merb-auth-core-1.1
Successfully installed merb-auth-more-1.1
Successfully installed merb-auth-slice-password-1.1
Successfully installed merb-auth-1.1
WARNING: description and summary are identical
mv merb-cache-1.1.gem pkg/merb-cache-1.1.gem
Successfully installed merb-cache-1.1
WARNING: no rubyforge_project specified
WARNING: description and summary are identical
mv merb-exceptions-1.1.gem pkg/merb-exceptions-1.1.gem
Successfully installed merb-exceptions-1.1
WARNING: description and summary are identical
mv merb-gen-1.1.gem pkg/merb-gen-1.1.gem
Successfully installed merb-gen-1.1
Writing executable wrapper /opt/local/bin/merb-gen
WARNING: description and summary are identical
mv merb-haml-1.1.gem pkg/merb-haml-1.1.gem
Successfully installed merb-haml-1.1
WARNING: description and summary are identical
mv merb-helpers-1.1.gem pkg/merb-helpers-1.1.gem
Successfully installed merb-helpers-1.1
WARNING: description and summary are identical
mv merb-mailer-1.1.gem pkg/merb-mailer-1.1.gem
Successfully installed merb-mailer-1.1
WARNING: description and summary are identical
mv merb-param-protection-1.1.gem pkg/merb-param-protection-1.1.gem
Successfully installed merb-param-protection-1.1
ERROR: could not find gem pkg/merb-more-1.1.gem locally or in a repository
I tried to go to next step without considering those errors.
$ cd merb/merb-core
$ sudo rake install
$ cd ../merb-auth
$ sudo rake install
They succeeded.
$ cd ~/tmp
$ merb-gen app my_first_merblog --template-engine=haml
$ cd my_first_blog
$ ls
Rakefile app/ autotest/ config/ doc/ gems/ merb/ public/ spec/ tasks/
cool.
$ merb-gen resource post title:string,body:string
Loading init file from /Users/ujihisa/tmp/my_first_merblog/config/init.rb
Loading /Users/ujihisa/tmp/my_first_merblog/config/environments/development.rb
~
~ FATAL: The gem merb_datamapper (>= 0, runtime), [] was not found
~
Noooo! I don't know whether the last errors caused or not, but I tried below
$ cd ~/git/merb/merb_datamapper/
$ sudo rake install
$ cd -
$ merb-gen resource post title:string,body:string
Loading init file from /Users/ujihisa/tmp/my_first_merblog/config/init.rb
Loading /Users/ujihisa/tmp/my_first_merblog/config/environments/development.rb
Generating with resource generator:
Loading /Users/ujihisa/tmp/my_first_merblog/config/environments/development.rb
Loading /Users/ujihisa/tmp/my_first_merblog/config/environments/development.rb
Loading /Users/ujihisa/tmp/my_first_merblog/config/environments/development.rb
[ADDED] spec/models/post_spec.rb
[ADDED] app/models/post.rb
[ADDED] spec/requests/posts_spec.rb
[ADDED] app/views/posts/show.html.haml
[ADDED] app/views/posts/index.html.haml
[ADDED] app/views/posts/edit.html.haml
[ADDED] app/views/posts/new.html.haml
[ADDED] app/controllers/posts.rb
[ADDED] app/helpers/posts_helper.rb
resources :posts route added to config/router.rb
Yay!
Contrary to rails, specs has been generated instead of tests. Let's spec!
$ rake spec
(in /Users/ujihisa/tmp/my_first_merblog)
Loading init file from /Users/ujihisa/tmp/my_first_merblog/config/init.rb
Loading /Users/ujihisa/tmp/my_first_merblog/config/environments/development.rb
./spec/models/../spec_helper.rb:17: uninitialized constant Merb::Test::ViewHelper (NameError)
from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/lib/spec/runner.rb:41:in `configure'
from ./spec/models/../spec_helper.rb:16
from ./spec/models/post_spec.rb:1:in `require'
from ./spec/models/post_spec.rb:1
from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/lib/spec/runner /example_group_runner.rb:15:in `load'
from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/lib/spec/runner /example_group_runner.rb:15:in `load_files'
from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/lib/spec/runner /example_group_runner.rb:14:in `each'
from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/lib/spec/runner /example_group_runner.rb:14:in `load_files'
from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/lib/spec/runner/options.rb:99:in `run_examples'
from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/lib/spec/runner /command_line.rb:9:in `run'
from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/bin/spec:4
rake aborted!
Command /opt/local/bin/ruby
-I"/opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/lib"
"/opt/local/lib/ruby/gems/1.8/gems/rspec-1.2.6/bin/spec"
"spec/models/post_spec.rb" "spec/requests/posts_spec.rb" --options
./spec/spec.opts failed
(See full trace by running task with --trace)
Hmm... There seem to be a lot of works to do.
Snap out of it. In accordance with the instruction of the tutorial, I did the following command,
$ merb-gen resource comment post_id:integer,name:string,body:string
and I fixed config/router.rb.
diff --git a/config/router.rb b/config/router.rb
index 173d73c..360618d 100644
--- a/config/router.rb
+++ b/config/router.rb
@@ -27,8 +27,9 @@
Merb.logger.info("Compiling routes...")
Merb::Router.prepare do
- resources :comments
- resources :posts
+ resources :posts do |p|
+ p.resources :comments
+ end
# RESTful routes
# resources :posts
@@ -43,4 +44,4 @@ Merb::Router.prepare do
# Change this for your home page to be available at /
# match('/').to(:controller => 'whatever', :action =>'index')
-end
\ No newline at end of file
+end
Then I set up the relationships, controller and view. This diff is very long, so I posted the diff to gist.
Let's run!
$ rake db:automigrate
$ merb
$ open http://localhost:4000
Cool!
But when I posted a comment to a post, an error occured.
Something is wrong. Action '1' was not found in Posts... At first I
suspected that config/routes.rb was wrong, but finally I found the cause is
in app/views/comments/_comment.html.haml. Following patch fixes the problem.
diff --git a/app/views/comments/_comment.html.haml b/app/views/comments/_comment.html.haml
index 7e54ce8..fcebb73 100644
--- a/app/views/comments/_comment.html.haml
+++ b/app/views/comments/_comment.html.haml
@@ -1,6 +1,6 @@
%p= error_messages_for :comment
-= form_for(:comment, :action => "/posts/#{@post.id}/comments") do
+= form_for(:comment, :action => "/posts/#{@post.id}/comments", :method => :post) do
%p= text_field :name, :name => "comment[name]"
%p= text_area :body
%p= submit "Comment"
The cause was the HTTP METHOD was put for some reason instead of desired
post. By specifying post explicitly, the problem was solved.
I fixed the turorial wiki, so a person who tries it will never meet the problem aftertime.
I deployed the sample merb application.
http://67.23.4.19:20090525/posts
The post number 20090525 is today's date.
This sample app server is already stopped.
Today I read the document of c.vim. Features that I'll use later are outlined below.
Key mappings to insert a template/snippet bellow.
Legend: (i) insert mode, (n) normal mode, (v) visual mode
\c* code -> comment /* */ (n,v)
\c/ code -> comment // (n,v)
\cc code -> comment // (n,v)
\co comment -> code (n,v)
\p< #include <> (n,i)
\p" #include "" (n,i)
I wonder why The first four key don't have operator-pending mode? We can
never commentout 3 lines without using visual mode.
There are a lot of key mappings to insert a template of a snippet. I'm doubtful about the effectiveness of those snippets. The most surprising one is below:
\i0 for( x=0; x<n; x+=1 ) (n,v,i)
Of course we can easily fix those templates. see
~/.vim/c-support/codesnippets/. For example, \p< doesn't insert #include
<> but #include\t<>, and even worse the snippet will inserted on the next
line, therefore I have to fix the feature or to decide not to use it.
In the document, it is written that
Syntax based folding can be enabled by adding the following lines to the file '~/.vim/syntax/c.vim':
syn region cBlock start="{" end="}" transparent fold set foldmethod=syntax " initially all folds open: set foldlevel=999
But I found that it does not work well. It has a lot of bug. Following setting works well:
" in ~/.vim/syntax/c.vim
set foldmethod=syntax
But I prefer that only functions are folded, so finally I deleted the file. I have to find how to do it.
\rc save and compile (n)
\rr run (n)
\ra set comand line arguments (n)
\rm run make (n)
\rg cmd. line arg. for make (n)
\rp run splint (n)
I don't understand of there is a special key mapping \rc or \rm instead of
using preexistent :make feature. I checked :compiler but it was not set.
I always set <space>m as :make, so I wrote below on my vimrc.
augroup MyCompiler
autocmd!
autocmd Filetype c nmap <buffer> <Space>m \rc
autocmd Filetype cpp nmap <buffer> <Space>m \rc
augroup END
\rr is OK. I can use both \rr feature which outputs temporary and
quickrun.vim which outputs permanentry.
I attended the Vancouver.rb meeting: Rubish with Howard Yeh AND Intro to Erlang with Ken Pratt. My notes are below -- while it doesn't make sense without the original talks.
Executable {Cmd, Pipe}, Job control, Context
(sh) ls a b c
(rb) ls 'a b c'
(sh) ls 'a b c'
(rb) ls.q 'a b c'
sed: one liner. Rubish has sed method.
(rb) find('. -name "*.el*').sed { p if File.ex... }.map {|f| ...
Be explict, fits well
Optimization and consistency
Grep
p prev if respond_to?(:prev)
Enumerable#collect)Executable#{exec!, each! map!}, Job#{wait} obj.extend(module).instance_eval { ... }
with method
<3 asynchronous message passing<3 tails recursionA URI notation is easy to be distinguished. There is almost no confusion about it. Therefore it may be OK that some programming languages have URI Literal. Unfortunately, I have never seen.
I added a something like a URI literal into Ruby.
def http(x)
"http://#{x}"
end
class Symbol
def /(o)
o
end
end
class String
def method_missing(*a, &b)
raise unless a.size == 1
"#{self}.#{a.first}"
end
def /(o)
"#{self}/#{o}"
end
end
def method_missing(*a, &b)
raise unless a.size == 1
a.first.to_s
end
p http://www.google.com/this/is/a/pen.html
#=> "http://www.google.com/this/is/a/pen.html"
Although this snippet supports only http, it is easy to be extended to handle https, ftp or gopher.
I fixed the code to support % notation and to return a URI object by a URI literal as _tad_ suggested. The new code is below:
require 'uri'
def http(x)
URI.parse "http://#{x}"
end
class Symbol
def /(o)
o
end
end
class String
def method_missing(*a, &b)
raise unless a.size == 1
"#{self}.#{a.first}"
end
def /(o)
"#{self}/#{o}"
end
def %(n)
"#{self}%#{n}"
end
end
class Integer
def method_missing(*a, &b)
raise unless a.size == 1
"#{self}.#{a.first}"
end
end
def method_missing(*a, &b)
raise unless a.size == 1
a.first.to_s
end
p http://www.google.com/this/is/a/pen.html
#=> #<URI::HTTP:0x7a8c8 URL:http://www.google.com/this/is/a/pen.html>
p http://www.google.com/this/is/a/aaa%20.html
#=> #<URI::HTTP:0x79c98 URL:http://www.google.com/this/is/a/aaa%20.html>
To tell the truth, I finished writing the code in a short time, but at that time blogger.vim didn't work. It tool very long time to fix blogger.vim, and then finally I succeeded it. blogger.vim will be version up soon.
Today I visited SFU Burnaby campus.
It took an hour to get to SFU. I had to transfer 2 times. The bus from the nearest station, the Production Way/University Station, to the campus was absolutely congested with students. I remembered the terrible commuter bus of my high school in Japan.
Meanwhile the campus was cool. There was something like relic atmosphere. I remembered the Japanese famous game Shadow of the Colossus.
I took an espresso in a cafeteria and then I took a class about the Human Interface.
And then I looked around mainly Computing Science department. I wanted to talk with people there but I was too nervous to do it.
After that I went to a library and read some journals about programming languages.
I wrote a Vim script blogger.vim which handles blogger (blogspot) by Vim. This entry is powered by the baby blogger.vim. Blogger.vim is the only one vim script which handles Blogger using metarw.
I wrote a ruby script blogger.rb and used it for blogger.vim. Blogger.rb is separated from blogger.vim, so you don't need if_ruby option for your vim.
Blogger.vim 1.0 has a lot of known bugs and unknown bugs. If you find a bug, please let me know it after reading the known bugs section of README.md.
enjoy!
When I was reading '[' section of parser.y,
7190 case '[':
7191 paren_nest++;
I got interested in how it will happen when paren_nest becomes huge. I tried this script:
(9995..11000).each do |n|
p n
eval '['*n + ']'*n
end
The result was
/var/folders/Dz/Dz5WpFSZGUaFLA8jp8kT5E+++TM/-Tmp-/v258465/130:3: (eval):1: compile error (SyntaxError)
(eval):1: memory exhausted
...[[[[[[[[[[[[[[[[[[[[[[[[[[[[[]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]...
^
from /var/folders/Dz/Dz5WpFSZGUaFLA8jp8kT5E+++TM/-Tmp-/v258465/130:1:in `eval'
from /var/folders/Dz/Dz5WpFSZGUaFLA8jp8kT5E+++TM/-Tmp-/v258465/130:3
from /var/folders/Dz/Dz5WpFSZGUaFLA8jp8kT5E+++TM/-Tmp-/v258465/130:1:in `each'
from /var/folders/Dz/Dz5WpFSZGUaFLA8jp8kT5E+++TM/-Tmp-/v258465/130:1
hmm
I committed some to Termtter. The following diff is the summary of my patches today.
diff --git a/lib/plugins/uri-open.rb b/lib/plugins/uri-open.rb
index 0afe73f..06a521b 100644
--- a/lib/plugins/uri-open.rb
+++ b/lib/plugins/uri-open.rb
@@ -8,44 +8,43 @@ module Termtter::Client
:points => [:output],
:exec_proc => lambda {|statuses, event|
statuses.each do |s|
- public_storage[:uris] += s[:text].scan(%r|https?://[^\s]+|)
+ public_storage[:uris] = s[:text].scan(%r|https?://[^\s]+|) + public_storage[:uris]
end
}
)
def self.open_uri(uri)
- unless config.plugins.uri_open.browser.empty?
- system config.plugins.uri_open.browser, uri
- else
- case RUBY_PLATFORM
- when /linux/
- system 'firefox', uri
- when /mswin(?!ce)|mingw|bccwin/
- system 'explorer', uri
+ cmd =
+ unless config.plugins.uri_open.browser.empty?
+ config.plugins.uri_open.browser
else
- system 'open', uri
+ case RUBY_PLATFORM
+ when /linux/; 'firefox'
+ when /mswin(?!ce)|mingw|bccwin/; 'explorer'
+ else; 'open'
+ end
end
- end
+ system cmd, uri
end
register_command(
:name => :'uri-open', :aliases => [:uo],
- :exec_proc => lambda{|arg|
+ :exec_proc => lambda {|arg|
case arg
- when /^\s+$/
- public_storage[:uris].each do |uri|
- open_uri(uri)
- end
- public_storage[:uris].clear
+ when ''
+ open_uri public_storage[:uris].shift
when /^\s*all\s*$/
- public_storage[:uris].each do |uri|
- open_uri(uri)
- end
- public_storage[:uris].clear
+ public_storage[:uris].
+ each {|uri| open_uri(uri) }.
+ clear
when /^\s*list\s*$/
- public_storage[:uris].each_with_index do |uri, index|
- puts "#{index}: #{uri}"
- end
+ public_storage[:uris].
+ enum_for(:each_with_index).
+ to_a.
+ reverse.
+ each do |uri, index|
+ puts "#{index}: #{uri}"
+ end
when /^\s*delete\s+(\d+)\s*$/
puts 'delete'
public_storage[:uris].delete_at($1.to_i)
@@ -53,19 +52,20 @@ module Termtter::Client
public_storage[:uris].clear
puts "clear uris"
when /^\s*(\d+)\s*$/
- open_uri(public_storage[:uris][$1.to_i])
- public_storage[:uris].delete_at($1.to_i)
+ open_uri(public_storage[:uris].delete_at($1.to_i))
+ else
+ puts "**parse error in uri-open**"
end
},
- :completion_proc => lambda{|cmd, arg|
- %w(all list delete clear).grep(/^#{Regexp.quote arg}/).map{|a| "#{cmd} #{a}"}
+ :completion_proc => lambda {|cmd, arg|
+ %w(all list delete clear).grep(/^#{Regexp.quote arg}/).map {|a| "#{cmd} #{a}" }
}
)
end
-# ~/.termtter
+# ~/.termtter/config
# plugin 'uri-open'
#
# see also: http://ujihisa.nowa.jp/entry/c3dd00c4e0
#
# KNOWN BUG
-# * In Debian, exit or C-c in the termtter kills your firefox.
+# * In Debian, exit or C-c in the termtter would kill your firefox.
I succeeded in adding a lisp like symbol literal to ruby by fixing parse.y.
diff --git a/parse.y b/parse.y
index e2e92ce..c9fbb03 100644
--- a/parse.y
+++ b/parse.y
@@ -6319,6 +6319,9 @@ static int
parser_yylex(struct parser_params *parser)
{
register int c;
+ int cs[1024];
+ int i;
+ char flag; // 't': sTring, 'y': sYmbol
int space_seen = 0;
int cmd_state;
enum lex_state_e last_state;
@@ -6631,8 +6634,26 @@ parser_yylex(struct parser_params *parser)
return tXSTRING_BEG;
case '\'':
- lex_strterm = NEW_STRTERM(str_squote, '\'', 0);
- return tSTRING_BEG;
+ flag = 'y'; // sYmbol by default
+ for (i=0; i<sizeof(cs); i++) {
+ cs[i] = nextc();
+ if (cs[i] == '\'') {
+ flag = 't'; // sTring
+ break;
+ }
+ if (cs[i] == '\n' || cs[i] == -1) {
+ break; // sYmbol
+ }
+ }
+ while (i >= 0)
+ pushback(cs[i--]);
+ if (flag == 't') {
+ lex_strterm = NEW_STRTERM(str_squote, '\'', 0);
+ return tSTRING_BEG;
+ } else {
+ lex_state = EXPR_FNAME;
+ return tSYMBEG;
+ }
case '?':
if (lex_state == EXPR_END || lex_state == EXPR_ENDARG) {
After applying this patch, we can write such like:
p 'aaa' #=> "aaa"
p 'bbb #=> :bbb
p 'ccc, true #=> :ccc
# true
p :ddd #=> :ddd
The followings are the methodology how it works:
Obviously, there are some known bugs:
p 'aaa, 'bbb
e.g.
p 'aaa
bbb'
To tell the truth, I wrote this patch just for my curiousity. I don't believe this syntax will harmonize well with Ruby.
When a single quote comes, parse.y will do:
case '\'':
lex_strterm = NEW_STRTERM(str_squote, '\'', 0);
return tSTRING_BEG;
This piece of codes is very same as a part of :'aaa'
NEW_STRTERM is a macro. It is a wrapper of a macro rb_node_newnode, which is a wrapper of a function node_newnode
#define NEW_STRTERM(func, term, paren) \
rb_node_newnode(NODE_STRTERM, (func), (term) | ((paren) << (CHAR_BIT * 2)), 0)
#define rb_node_newnode(type, a1, a2, a3) node_newnode(parser, type, a1, a2, a3)
static NODE*
node_newnode(struct parser_params *parser, enum node_type type, VALUE a0, VALUE a1, VALUE a2)
{
NODE *n = (rb_node_newnode)(type, a0, a1, a2);
nd_set_line(n, ruby_sourceline);
return n;
}
The last function node_newnode calls rb_node_newnode, that is node_newnode itself, recursively.
Here is the node_newnode which macro is expanded:
static NODE*
node_newnode(struct parser_params *parser, enum node_type type, VALUE a0, VALUE a1, VALUE a2)
{
NODE *n = node_newnode(parser, type, a0, a1, a2);
nd_set_line(n, ruby_sourceline);
return n;
}
It's mysterious. node_newnode seems infinite recursion without any terminate conditions. Why does it work?
In Ruby, there are a lot of usages of colon.
The following is an excerpt from parse.y relates a colon:
case ':':
c = nextc();
if (c == ':') {
if (IS_BEG() ||
lex_state == EXPR_CLASS || (IS_ARG() && space_seen)) {
lex_state = EXPR_BEG;
return tCOLON3;
}
lex_state = EXPR_DOT;
return tCOLON2;
}
if (lex_state == EXPR_END || lex_state == EXPR_ENDARG || (c != -1 && ISSPACE(c))) {
pushback(c);
lex_state = EXPR_BEG;
return ':';
}
switch (c) {
case '\'':
lex_strterm = NEW_STRTERM(str_ssym, c, 0);
break;
case '"':
lex_strterm = NEW_STRTERM(str_dsym, c, 0);
break;
default:
pushback(c);
break;
}
lex_state = EXPR_FNAME;
return tSYMBEG;
If the next character of ':' is ':', in a nutshell if '::' has come, it returns tCOLON3 (:: at the very left) or tCOLON2 (:: at the right hand). Otherwise if the colon is just after expressions, it's a conditional operator. Ditto if the next character is a space. Otherwise finally the colon is a prefix of symbol.
I've never known that we can have a newline after ::!
class A::
B
end
It's valid.
OK... So, let's try to add a new literal :-) which has equivalent to =>.
diff --git a/parse.y b/parse.y
index e2e92ce..8e49bf4 100644
--- a/parse.y
+++ b/parse.y
@@ -7082,6 +7082,9 @@ parser_yylex(struct parser_params *parser)
case ':':
c = nextc();
+ if (c == '-' && nextc() == ')') {
+ return tASSOC;
+ }
if (c == ':') {
if (IS_BEG() ||
lex_state == EXPR_CLASS || (IS_ARG() && space_seen)) {
That's easy.
$ ./ruby -e 'p({ 1 :-) 2 })'
{1=>2}
cool!
The documentations about Array#<=> are:
For example:
[1, 2, 3, 4] <=> [1, 2, 3, 3] #=> 1
[1, 2, 3, 4] <=> [1, 2, 3, 4] #=> 0
[1, 2, 3, 4] <=> [1, 2, 3, 5] #=> -1
[1, 2, 3, 4] <=> [1, 2, 3] #=> 1
The implementation in MRI 1.9 is:
VALUE
rb_ary_cmp(VALUE ary1, VALUE ary2)
{
long len;
VALUE v;
ary2 = to_ary(ary2);
if (ary1 == ary2) return INT2FIX(0);
v = rb_exec_recursive(recursive_cmp, ary1, ary2);
if (v != Qundef) return v;
len = RARRAY_LEN(ary1) - RARRAY_LEN(ary2);
if (len == 0) return INT2FIX(0);
if (len > 0) return INT2FIX(1);
return INT2FIX(-1);
}
static VALUE
recursive_cmp(VALUE ary1, VALUE ary2, int recur)
{
long i, len;
if (recur) return Qnil;
len = RARRAY_LEN(ary1);
if (len > RARRAY_LEN(ary2)) {
len = RARRAY_LEN(ary2);
}
for (i=0; i<len; i++) {
VALUE v = rb_funcall(rb_ary_elt(ary1, i), id_cmp, 1, rb_ary_elt(ary2, i));
if (v != INT2FIX(0)) {
return v;
}
}
return Qundef;
}
I translated it from C to Ruby literally:
class Array
def yet_another_cmp(you)
you = you.to_ary
return 0 if self == you
v = nil
(0...[self.length, you.length].min).each do |i|
v = self[i] <=> you[i]
return v if v != 0
end
len = self.length - you.length
return 0 if len == 0
return 1 if len > 0
-1
end
end
It works exactly the same.
You may think it is easy to write a simpler equivalent implement with Array#zip, but unfortunately I found that it was not so simple. The following is the simplest code I can write. Of course it works exactly the same as original <=>.
class Array
def simple_cmp(you)
self.zip(you) {|x, y|
break if (x && y).nil?
(v = x <=> y) == 0 or return v
}
self.length <=> you.length
end
end
In conclusion, Array#<=> itself is complicated one.
Enjoy your space travel!
A bugfix patch may make Array#to_s slow. I am finding out how slow it becomes.
That patch changes the definition of Array#to_s from:
rb_define_method(rb_cArray, "to_s", rb_ary_inspect, 0);
rb_define_method(rb_cArray, "inspect", rb_ary_inspect, 0);
to:
rb_define_method(rb_cArray, "inspect", rb_ary_inspect, 0);
rb_define_alias(rb_cArray, "to_s", "inspect");
This change effects only in the array has itself recursively.
Benchmark code I use is:
require 'benchmark'
short_a = Array.new(100) { rand }
long_a = Array.new(10000) { rand }
Benchmark.bmbm do |b|
b.report do
1000.times do
short_a.to_s
end
end
b.report do
10.times do
long_a.to_s
end
end
end
And the results are below.
Conventional (before the patch applied)
Rehearsal ------------------------------------
0.810000 0.010000 0.820000 ( 0.836625)
0.870000 0.010000 0.880000 ( 0.901661)
--------------------------- total: 1.700000sec
user system total real
0.740000 0.010000 0.750000 ( 0.748501)
0.770000 0.010000 0.780000 ( 0.801869)
Current (after the patch applied)
Rehearsal ------------------------------------
0.820000 0.000000 0.820000 ( 0.852360)
0.860000 0.010000 0.870000 ( 0.897602)
--------------------------- total: 1.690000sec
user system total real
0.850000 0.010000 0.860000 ( 0.873125)
0.830000 0.010000 0.840000 ( 0.871903)
There are certainly slow changes, but they seem enough slight. What do you think about it?
