From: Magnus Holm <judofyr@...>
Date: 2013-05-10T16:48:16+09:00
Subject: [ruby-core:54898] Re: [ruby-trunk - Feature #8321] Ripper: I would like coordinates for keywords

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On Fri, May 10, 2013 at 9:13 AM, bozhidar (Bozhidar Batsov) <
bozhidar@batsov.com> wrote:

>
> Issue #8321 has been updated by bozhidar (Bozhidar Batsov).
>
>
> The example outlined in the proposal is exactly what I think we need.  A
> lot of Ruby code analysis tools need exact coordinates of keywords and
> currently there is no easy and reliable way to get them.  This is even more
> important, now that you've rejected #8383


You can use the `parser` gem: https://github.com/whitequark/parser

It gives you a nice AST together with source maps:

  require 'parser/current'
  ast = Parser::CurrentRuby.parse('if a; b; else; c; end')

(if
  (send nil :a)
  (send nil :b)
  (send nil :c))

  ast.source_map.expression # => 0...21 (the whole expression)
  ast.source_map.keyword # => 0...2 (the "if")
  ast.source_map.begin # => 4...5 (the ";")
  ast.source_map.else # => 9...13 (the "else")
  ast.source_map.end # => 18...12 (the "end")

And you can then check the children for more data:

  (cond, tbranch, fbranch) = *ast

  cond.source_map.expression # => 3...4 ("a")

All of these return a Source::Range which allows you to extract the source
and lineno/column:

  cond.source_map.expression.to_source # => "a"
  cond.source_map.expression.line # => 1
  cond.source_map.expression.column # => 3

Parser also supports 1.8, 1.9, 2.0 and 2.1/trunk, *and* it ships with a
rewriter tool:
http://whitequark.org/blog/2013/04/26/lets-play-with-ruby-code/

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<div dir=3D"ltr"><br><div class=3D"gmail_extra"><div class=3D"gmail_quote">=
On Fri, May 10, 2013 at 9:13 AM, bozhidar (Bozhidar Batsov) <span dir=3D"lt=
r">&lt;<a href=3D"mailto:bozhidar@batsov.com" target=3D"_blank">bozhidar@ba=
tsov.com</a>&gt;</span> wrote:<br>

<blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-=
left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;p=
adding-left:1ex"><br>
Issue #8321 has been updated by bozhidar (Bozhidar Batsov).<br>
<br>
<br>
The example outlined in the proposal is exactly what I think we need. =C2=
=A0A lot of Ruby code analysis tools need exact coordinates of keywords and=
 currently there is no easy and reliable way to get them. =C2=A0This is eve=
n more important, now that you&#39;ve rejected #8383</blockquote>

<div><br></div><div style>You can use the `parser` gem: <a href=3D"https://=
github.com/whitequark/parser">https://github.com/whitequark/parser</a></div=
><div style><br></div><div style>It gives you a nice AST together with sour=
ce maps:</div>

<div style><br></div><div style>=C2=A0 require &#39;parser/current&#39;</di=
v><div style>=C2=A0 ast =3D Parser::CurrentRuby.parse(&#39;if a; b; else; c=
; end&#39;)</div><div style><br></div><div style><div><div>(if</div><div>=
=C2=A0 (send nil :a)</div>

<div>=C2=A0 (send nil :b)</div><div>=C2=A0 (send nil :c))</div></div><div><=
br></div><div>=C2=A0 ast.source_map.expression # =3D&gt; 0...21 (the whole =
expression)</div><div>=C2=A0 ast.source_map.keyword # =3D&gt; 0...2 (the &q=
uot;if&quot;)</div>
<div style>
=C2=A0 ast.source_map.begin # =3D&gt; 4...5 (the &quot;;&quot;)</div><div s=
tyle>=C2=A0 ast.source_map.else # =3D&gt; 9...13 (the &quot;else&quot;)</di=
v><div style>=C2=A0 ast.source_map.end # =3D&gt; 18...12 (the &quot;end&quo=
t;)</div><div style>

<br></div><div style>And you can then check the children for more data:</di=
v><div style><br></div><div style>=C2=A0 (cond, tbranch, fbranch) =3D *ast<=
/div><div style><br></div><div style>=C2=A0 cond.source_map.expression # =
=3D&gt; 3...4 (&quot;a&quot;)</div>

<div style><br></div><div style>All of these return a Source::Range which a=
llows you to extract the source and lineno/column:</div><div style><br></di=
v><div style>=C2=A0 cond.source_map.expression.to_source # =3D&gt; &quot;a&=
quot;</div>

<div style>=C2=A0 cond.source_map.expression.line # =3D&gt; 1</div><div sty=
le>=C2=A0 cond.source_map.expression.column # =3D&gt; 3</div><div style><br=
></div><div style>Parser also supports 1.8, 1.9, 2.0 and 2.1/trunk, *and* i=
t ships with a rewriter tool:=C2=A0<a href=3D"http://whitequark.org/blog/20=
13/04/26/lets-play-with-ruby-code/">http://whitequark.org/blog/2013/04/26/l=
ets-play-with-ruby-code/</a></div>

</div></div></div></div>

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