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*To*: "srfi-110" <srfi-110@xxxxxxxxxxxxxxxxx>*Subject*: Re: The ". $" notation*From*: "David A. Wheeler" <dwheeler@xxxxxxxxxxxx>*Date*: Mon, 18 Mar 2013 12:25:36 -0400 (EDT)*Delivered-to*: srfi-110@xxxxxxxxxxxxxxxxx*In-reply-to*: <CAF+kUQX3ghwPo3Jk95Na0zY3kuxtbLQ-RyzZvthYo7Q-soTXyQ@xxxxxxxxxxxxxx>*References*: <CAF+kUQX5mK=VStZyu6zfGQj9SE+J4D=dHPF6+d-T-5a+tZ7XvA@xxxxxxxxxxxxxx> <20130317.154441.695066990312419885.shiro@xxxxxxxx> <CAF+kUQX3ghwPo3Jk95Na0zY3kuxtbLQ-RyzZvthYo7Q-soTXyQ@xxxxxxxxxxxxxx>*Reply-to*: dwheeler@xxxxxxxxxxxx

Alan Manuel Gloria: > >> 1. Allow "foo . EOL INDENT x ..." ==> "(foo . (x ...))" > >> 2. Allow "foo . $ x ..." ==> "(foo x ...)" Unfortunately, those 2 forms greatly differ in ease-of-implementation. The *second* form is easy to add to the BNF. Here's the patch: diff --git a/sweet.g b/sweet.g index 82055ea..937e54d 100644 --- a/sweet.g +++ b/sweet.g @@ -1061,6 +1061,7 @@ rest returns [Object v] (pn=n_expr hspace* (n_expr error)? {$v = $pn.v;} | COLLECTING hspace* pc=collecting_tail hspace* (n_expr error)? {$v = $pc.v;} + | SUBLIST hspace* ps=rest {$v = $ps.v;} | empty {$v = list(".");}) | empty {$v = list(".");}) | scomment hspace* (sr=rest {$v = $sr.v;} | empty {$v = null;} ) So we could easily support form #2, and I don't see any big downside. I'll post the ANTLR patch on git; we can revert it later, or implement it in the Scheme implementation, depending on what people say. I don't see an obvious way to add the first form to the BNF, though, and I don't think we should reorganize everything for such a bizarre case. Also, I can see form #1 being created accidentally, so *preventing* it seems wise. Granted, that's a minor inconsistency, but ". $" is such a bizarre useless sequence that I'm going to lose any sleep over it (if we add it). --- David A. Wheeler

**Follow-Ups**:**Re: The ". $" notation***From:*Alan Manuel Gloria

**References**:**The ". $" notation (was: Re: how useful are collecting lists?)***From:*Alan Manuel Gloria

**Re: The ". $" notation***From:*Shiro Kawai

**Re: The ". $" notation***From:*Alan Manuel Gloria

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