[erlang-questions] Are newlines significant in Erlang grammar?

Ryan Molden ryanmolden@REDACTED
Tue Dec 20 18:33:32 CET 2011

Sure, but I was trying to avoid sprinking [\t\r\n ]* tokens everywhere
throughout my grammar. My lexer currently ignores whitespace outside of
comments and string literals and my parser works off the tokens my lexer

If what you are saying is correct it sounds like I can't do that, which
means my parser's grammar explodes with tons of 'oh and there can be
whitespace here, or needs to be whitespace here' kind of tokens :(
On Tue, Dec 20, 2011 at 9:04 AM, Fred Hebert <mononcqc@REDACTED> wrote:

> It can be any whitespace, not necessarily new lines.
> On Tue, Dec 20, 2011 at 11:45 AM, Ryan Molden <ryanmolden@REDACTED>wrote:
>> I have been playing around with making a lexer/parser for Erlang using
>> boost::spirit and using the YRL from lib\stdlib-1.17.5\src\erl_parse.yrl as
>> my grammar.  It isn't specifically called out there (or anywhere else I can
>> find), but I assume that newlines are significant and implied as input
>> terminators?
>> For instance the following is accepted by the compiler (ignore the
>> meaninglessness/infinite recursion of blah)
>> -module .foo.
>> blah(F)->blah(F-1).
>> However, if I put it all on one line, like so:
>> -module .foo.blah(F)->blah(F-1).
>> it is not accepted. It seems to be because .foo.blah is being parsed as a
>> single instance of expr_900, which is defined as
>> expr_900 -> '.' atom
>> expr_900 -> expr_900 '.' atom
>> expr_900 -> expr_max
>> I am fine treating newlines as input terminators but it isn't clear which
>> non-terminals require the presence of a newline and which don't.
>> Ryan
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