Damian Conway wrote:
Alternatively, you could define separate rules for the three cases:
{
state @indents = 0;
rule indent {
^^ $:=(\h*)
{ $ = expand_tabs($).chars }
<( $ > @indents[-1] )>
{ let @indents = (@indents, $) }
On 9/8/05, Larry Wall <[EMAIL PROTECTED]> wrote:
> Okay, how do you tell the difference between
>
> if foo1
> bar1
> if foo2
> bar2
> if foo3
> bar3
> else
>
On Thu, Sep 08, 2005 at 07:57:43PM -0400, Collin Winter wrote:
: On 9/8/05, Larry Wall <[EMAIL PROTECTED]> wrote:
: > It seems to me you need a stack of levels so you know how many
: > indentation levels to pop off. Otherwise you can't parse this:
: >
: > if foo1
: > bar1
On 9/8/05, Larry Wall <[EMAIL PROTECTED]> wrote:
> It seems to me you need a stack of levels so you know how many
> indentation levels to pop off. Otherwise you can't parse this:
>
> if foo1
> bar1
> if foo2
> bar2
>
To solve Dave's particular problem, you don't need any new features. Just:
rule indentation {
^^ $:=(\h*)
{ state @indents = 0;
my $new_indent = expand_tabs($).chars;
let @indents = @indents;
pop @indents while @indents && $new_indent <= @
Larry,
On Sep 8, 2005, at 5:07 PM, Larry Wall wrote:
On Thu, Sep 08, 2005 at 04:52:52PM -0400, Stevan Little wrote:
: But what if I want to do this?
:
: class Foo {
: my %:stuff;
: method keys (Class $c:) {
: %:stuff.keys();
: }
: }
:
: How can I get at my namespa
[EMAIL PROTECTED] (Larry Wall) writes:
> So let's go ahead and make it ??!!. (At least this week...)
I hereby christen this "the interrobang operator".
(http://en.wikipedia.org/wiki/Interrobang)
--
"Your fault: core dumped"
-- MegaHAL
On Thu, 2005-09-08 at 14:59 -0700, Greg Woodhouse wrote:
> I agree that simply using terms like this means indentation grammars
> are problematic -- or does it? One thing that bothers me is that
> *people* don't seem to have a great deal of difficulty with them. Why
> not?
People can parse multi-
Come to think of it...I had in mind a sequence of "skip" statements,
that would back out of a level one at a time, until you finally reached
the desired level. But, I think maybe these "skip" statements
essentially play the role of what you called "positive unindent tokens"
(I like that term).
I a
What I had in mind is really no different from the stateful lexer
previously proposed. Unless I'm mistaken, an abstract model might be a
language over {0, 1, 2} where each 1 or 2 must be prececed by a run of
1 or more 0's, but each run differ in length from the preceding one by
0, 1 or -1. But that
On Thu, Sep 08, 2005 at 02:16:33PM -0700, Greg Woodhouse wrote:
: In the case of the
: "indentation grammar", then the (one) stack in a push-down automaton is
: basically used up keeping track of the indentation level. But you don't
: need a whole stack to keep track of indntation level, just a reg
That's something I've been thinking about, too. There are a lot of
"interesting" languages that cannot be described by context free
grammars (such as {empty, 012, 001122, 000111222, ...} but very simple
enhancements do make them easy to recognize. In the case of the
"indentation grammar", then the
On Thu, Sep 08, 2005 at 04:52:52PM -0400, Stevan Little wrote:
: But what if I want to do this?
:
: class Foo {
: my %:stuff;
: method keys (Class $c:) {
: %:stuff.keys();
: }
: }
:
: How can I get at my namespace now? How would I disambiguiate that call?
: Doing
On Thu, Sep 08, 2005 at 08:37:21AM -0700, Dave Whipp wrote:
: If I want to parse a language that is sensitive to whitespace
: indentation (e.g. Python, Haskell), how do I do it using P6 rules/grammars?
:
: The way I'd usually handle it is to have a lexer that examines leading
: whitespace and co
Larry,
On Sep 8, 2005, at 2:30 PM, Larry Wall wrote:
On Wed, Sep 07, 2005 at 03:00:29PM -0400, Stevan Little wrote:
: Also, is there anyway to iterate over the keys in the namespace? The
: old way would be to do something like keys(%Foo::). Is something like
: this possible with the new way?
Su
On Wed, Sep 07, 2005 at 03:00:29PM -0400, Stevan Little wrote:
: If methods and subs are in the same namespace, and both have the &
: sigil, what about instance attributes and class attributes? Is this
: legal?
:
: class Foo {
: my $.bar;
: has $.bar;
: }
:
: Part of me thinks that
On 9/8/05, Benjamin Smith <[EMAIL PROTECTED]> wrote:
> Pugs currently implements &infix: as an ugly version of the
> &infix: operator.
>
> Are these in the spec?
No they are not. Destroy!
Luke
If I want to parse a language that is sensitive to whitespace
indentation (e.g. Python, Haskell), how do I do it using P6 rules/grammars?
The way I'd usually handle it is to have a lexer that examines leading
whitespace and converts it into "indent" and "unindent" tokens. The
grammer can then
Pugs currently implements &infix: as an ugly version of the
&infix: operator.
Are these in the spec?
If so, how does !! interact with the second part of the new ??!!
replacement for ??:: ?
--
Benjamin "integral" Smith <[EMAIL PROTECTED], [EMAIL PROTECTED]>
19 matches
Mail list logo
