Why not adopt "Python Style" indentation for Ruby?

Ruby
41

On 5/18/07, Trans [email protected] wrote:

Putting a special character at the beginning of every line that is

I can’t count how many times I’ve forgotten “do”. Sometimes I have
wished a colon could “induce” the block:
That puzzles me, would you not forget the “:” then? Or do you have a
lot of Python experience. Not that I think bad of the “:” syntax, just
wondering.

Robert

42

“Yukihiro M.” [email protected] wrote in message
news:[email protected]…

|class/module/def/do/begin), ie:

For your information, 1.9 once had exact same syntax you’ve proposed
for a short while. I have a time machine. The idea was abandoned
since it caused serious unreadability.
always? may be real cause was abuse of this syntax?

well, if suffix did not work,
can we try prefix syntax for ‘end’-less constructs?
(if not has been tried before)
suggestion:
:& - prefixes ‘single statement body’ code block in
class/module/def/unless/then/else/while/until
#- samples
if cond :& puts a
if cond : puts a else :& puts b
while cond :& puts a
for var in expr :& puts var
# also valid:

if cond :& (puts a; puts b)
while cond :& begin puts a end

#- single statements ‘chain’
unless cond_a
:& for ea in expr
:& for eb in ezpr
:& if cond(ea, eb)
:& do_smthng
#- simple functor with local state
class<<fib=Object.new
:& def get(m)
:& (@fh||=Hash.new{|h,n|h[n]=n<2?n:h[n-1]+h[n-2]})[m]
fib.get 10
#-> 55

BRs
Sergey

43

On May 18, 2:41 pm, Jeremy H. [email protected] wrote:

On 2007-05-18, gga [email protected] wrote:

No editor I am aware knows how to match indentation yet or do/end
contexts (not that it could not be coded, thou).

Emacs + ruby-mode.el understands do/end just fine.

Regards,

Jeremy H.

No, it doesn’t. When I type a close brace in emacs, I get the
corresponding line where the matching brace matches (hilited if
visible in the page, or in the modeline if not).
When I position myself next to a brace, I get the same hiliting
happening. Can’t recall if that’s a feature of hilite or the electric
mode of emacs.
However, whenever I type “end” to close a block, I have NO clue where
the block begins. And if it is code I did not write, not knowing
where the code begins is a killer.
Being emacs, I could potentially hack the lisp code to handle do/end
blocks properly (or indentation too). I haven’t seen anyone do it yet
(and publically give it away).

44

On May 19, 2:38 am, “Robert D.” [email protected] wrote:

~ print n
~ puts

I can’t count how many times I’ve forgotten “do”. Sometimes I have
wished a colon could “induce” the block:

That puzzles me, would you not forget the “:” then? Or do you have a
lot of Python experience. Not that I think bad of the “:” syntax, just
wondering.

Hehe. Probably so. I’m not a hisser :wink: But I think I would forget the
colon much less often, especially given it created indention
significance.

T.

45

On May 18, 4:23 am, Chris D. [email protected] wrote:

…
with no reduction in meaning, yet 25% fewer lines of code.

What are the reasons why this isn’t used/implemented/liked? It would
be a small change to the interpreter. Enabling meaningful indentation
would only make ‘end’ optional, not invalid; backwards compatibility
wouldn’t be a problem.

(I use both Ruby and Python. I think indentation is one of the few
language features where Python leads Ruby.)

I personally prefer that ‘end’ be in place, so that all ruby code is
readable. I personally believe there may be something wrong with a
syntax which sacrifices explicit readability (for everyone, not just
python programmers) for increased typing speed and the illusory gain
of ‘fewer LOC’. This was one of the major reasons which convinced me
to use ruby instead of python.

46

On Sun, May 20, 2007 at 12:05:06AM +0900, Brendan wrote:

language features where Python leads Ruby.)

I personally prefer that ‘end’ be in place, so that all ruby code is
readable. I personally believe there may be something wrong with a
syntax which sacrifices explicit readability (for everyone, not just
python programmers) for increased typing speed and the illusory gain
of ‘fewer LOC’. This was one of the major reasons which convinced me
to use ruby instead of python.

I, personally, don’t have an argument on principle like that for my own
preferences in this matter. I just like the fact that an “end” makes it
look more complete to me. Reading Python code always makes me feel like
my eyes are just going to trail off the right-hand edge of the page
because the “shape” of the code never brings me back to the leftmost
edge, the way code “should”.

When I look at Python code, and ponder the way it does things so
differently from Ruby regarding delimiters and indentation (the same
thing in Python), it seems to me that Python was created for people who
write code in a particular mindset, and it’s not a mindset I share when
I’m writing code. I guess maybe some people, when writing code, think
in footnote hierarchies, while others (like me) think in nested scopes.

That’s just an off-the-cuff hypothesis.

47

Chad P. wrote:

(I use both Ruby and Python. I think indentation is one of the few
look more complete to me. Reading Python code always makes me feel like

That’s just an off-the-cuff hypothesis.

I’ve been watching this debate go by for some time, and I’m not sure
this sort of thing can ever be solved, but here are my personal
opinions:

  1. When you come right down to it, there are only a few basic syntax
    styles that have survived the test of time. Most languages, including
    C, Ruby, Pascal and Perl, use some variant of the Algol 60 syntax. The
    other “survivors” are the Lisp/Scheme variant of prefix notation,
    Forth’s postfix notation, and the regular expression syntax. I suppose
    assembly language syntax has also survived, and FORTRAN and COBOL, but I
    don’t think anyone would design a new language with those.

  2. I think Python’s “variant” of Algol 60 notation is less than
    satisfactory, but I also have problems with the liberality present in
    the syntax of Perl and Ruby. I don’t like to make the reader or parser
    work any harder than necessary just for the convenience of the coder. So
    I like explicit delimiters like curly braces, parentheses, mandatory
    semicolons at the end of statements, begin/end pairs, etc. for the Algol
    60 languages. Lisp/Scheme and Forth were deliberately designed to make
    the parser’s job trivial, and I like them too. :slight_smile:

  3. I’ve pretty much given up on the dream that I’ll be able to program
    in one language only, although some languages are close enough. At the
    moment, I can get just about everything done in either Perl or R, with
    the other languages simply being fun to learn and use but not essential.
    I could probably eliminate Perl if there were more R programmers, but
    there aren’t and won’t be, because R is designed for scientists and
    mathematicians, not business people.

48

Trans schrieb:

~ n.times do
~ print n
~ puts

But I don’t think a line prefix is worth the trouble.

Trouble? – I want the editor to insert the prefix, of course.
Some editors are already able to do this with line comments,
so they can be adapted easily.

Sven

49

On 19.05.2007 20:48, M. Edward (Ed) Borasky wrote:

  1. I think Python’s “variant” of Algol 60 notation is less than
    satisfactory, but I also have problems with the liberality present in
    the syntax of Perl and Ruby. I don’t like to make the reader or parser
    work any harder than necessary just for the convenience of the coder.

I would understand why you would want to make the reader’s job easier -
but the parser? That’s just a piece of software and I believe that we
should always strive to make software easier to use for humans not
machines.

Besides of that, personally I don’t find the current Ruby syntax hard to
read. Do you have some examples where you feel that reading Ruby is
made hard(er) because of the liberties you mention?

Kind regards

robert

50

On May 18, 12:58 pm, “Eric M.” [email protected] wrote:

these errors can be painful to track down in a large file with lots of
(I sometimes put debug statements flush left so that it’s a simple
/^p to search for them. Can’t do that with scope controlled by
whitespace. Dumb, dumb, dumb, dumb.)

That is the exact same case I find the indentation thing gets in the
way. I had to change my way of putting in print debug statements
(same as yours). Every language makes you change your ways a bit. Of
course python’s debug facilities (pdb) are much better than ruby’s so

Well, I think that’s going to change over the next year. If you
haven’t tried Ken Sibilev’s ruby-debug,
http://rubyforge.org/projects/ruby-debug/
give it a shot. Over the last year it has improved quite a bit and I
expect over the next year it will make the same steady progress. I’m
hoping the next release will have a user manual, and possibly start
adding some regression tests (which by the way pdb doesn’t currently
have).

As someone who’s a little bit familiar with both debuggers, I think
the design of ruby-debug is the cleaner and more flexible. In fact, I
think it’s the best organized debugger of any that I’ve seen so far.
(But then. as it grows…)

51

Quoting Robert K. [email protected]:

Besides of that, personally I don’t find the current Ruby syntax hard to
read. Do you have some examples where you feel that reading Ruby is
made hard(er) because of the liberties you mention?

Kind regards

robert

I can think of three examples right off the top of my head: Rails, Rake
and
RSpec. There’s something really eerie about seeing code like that. You
know
it works, but you can’t figure out why or how.

52

On 20/05/07, [email protected] [email protected] wrote:

Quoting Robert K. [email protected]:

Besides of that, personally I don’t find the current Ruby syntax hard to
read. Do you have some examples where you feel that reading Ruby is
made hard(er) because of the liberties you mention?

I can think of three examples right off the top of my head: Rails, Rake and
RSpec. There’s something really eerie about seeing code like that. You know
it works, but you can’t figure out why or how.

And you think replacing do/end with indentation would help?

I really can’t see how - could you give an example?

53

IMHO, at least in complicated cases, the reader has to emulate a
parer, so both are the same.

Whenever there is syntax that’s tricky to parse, it’s also tricky to
read.

See pythons space-vs-tab problem, for example.

Aur

54

Trans wrote:

On May 18, 5:22 pm, Sven S. [email protected] wrote:

but would provide a way to use significant indentation if one really
wants to.

If “~” were that special character, it would look like that:
~ 5.times do |n|
~ n.times do
~ print n
~ puts

I can’t count how many times I’ve forgotten “do”. Sometimes I have
wished a colon could “induce” the block:

5.times |n|:
n.times:
print n
puts

But I don’t think a line prefix is worth the trouble.

T.

I totally agree. A line pre-fix is a bit pointless in my opinion,
although I am in favour in moving towards a Python-style indentation
syntax. As for the ‘do’ issue I don’t see why it can’t be removed, if
something is always expected then you can just assume its there, right?

5.times do |n|
n.times do
print n
end
puts
end

(Or using the ‘:’ instead) Could just be:

5.times |n|
n.times
print n
end
puts
end

55

On 5/20/07, Peter M. [email protected] wrote:

T.
puts

Sorry, but how would you handle block_given? without parameters?

56

On 5/20/07, Dick D. [email protected] wrote:

And you think replacing do/end with indentation would help?

I really can’t see how - could you give an example?

Let’s try:

describe ‘myself’
it ‘should be readable’
lambda
@reader.reading
.should change
@reader.knowledge
.by(text.amount)

pretty much impossible, if you ask me :slight_smile:

same in usual ruby now

describe ‘myself’ do
it ‘should be readable’
lambda{ @reader.reading }.
should change{ @reader.knowledge }.
by(text.amount)
end
end

well?

57

Michael F. wrote:

On 5/20/07, Peter M. [email protected] wrote:

T.
puts

Sorry, but how would you handle block_given? without parameters?

I’m still quite new to Ruby, so I’m not entirely sure what you mean,
could you explain what you feel the problem would be please?

58

On 20/05/07, Michael F. [email protected] wrote:

On 5/20/07, Dick D. [email protected] wrote:

  @reader.reading
lambda{ @reader.reading }.
  should change{ @reader.knowledge }.
  by(text.amount)

end
end

well?

The only extra words there are do/end and you could replace them
with {} if they really bothered you.

If you’re saying you personally don’t like do/end blocks, then you’re
as entitled to that opinion as anyone else, but I don’t see this as
making
DSLs any more or less comprehensible personally

59

On 5/20/07, Dick D. [email protected] wrote:

describe ‘myself’

The only extra words there are do/end and you could replace them
with {} if they really bothered you.

If you’re saying you personally don’t like do/end blocks, then you’re
as entitled to that opinion as anyone else, but I don’t see this as making
DSLs any more or less comprehensible personally

uh, actually that was an example that i can’t interpret the
indentation. I do like the idea of supporting indentation, but not
within ruby.
It’s just getting into a mess with method-calls with blocks, manual
lambdas and doing methodchains like foo{bar}.duh{x} - it’s not really
about the braces but about the possibility to write that code in a
different syntax at all.

If someone is brighter than me, you’re welcome to propose alternatives
:slight_smile:

60

On May 18, 8:23 am, Chris D. [email protected] wrote:

As far as I can see, the ‘end’ keyword is ‘repeating yourself’ when
used with properly indented code.

Maybe it is maybe it isn’t. Personally I’m an ‘end’ man. I like my
blocks.

It would be easier if you learnt to type, or used editor macros.

(I use both Ruby and Python. I think indentation is one of the few
language features where Python leads Ruby.

If this post generates a positive response, I’ll make a patch for Ruby
1.9.

Nope, leave the language as it is. I like it unaltered thank you very
much.

However I’ve never understood why there has to be ‘one true syntax’
for any computer language. As long as the syntax generates the same
ASTs in the interpreter I can’t see why you couldn’t choose the syntax
you prefer - whether that is whitespace indentation, or the symbolic
mush of the ‘C’ derived languages.