[stringtemplate-interest] "".."" won't work

Terence Parr parrt at cs.usfca.edu
Wed Apr 6 10:35:46 PDT 2011 

Yeah,That is what I was thinking before. Ignoring indentation, particularly in front of conditionals seems reasonable. On the other hand what about indentation in front of text?

t() ::= <%
	start
	<if(x)>
		<x>
		foo
	<endif>
	end
%>

 should all that be ignored as equivalent to:

t() ::= <%
start
<if(x)>
<x>
foo
endif>
end
%>

I like the idea of throwing away indentation in front of conditionals; not sure about in front of text, but probably should for consistency.

T

On Apr 5, 2011, at 9:24 PM, Sam Harwell wrote:

> I still don’t see how <% %> would lead to implementation or usage problems. Can anyone give a concrete example where it breaks?
>  
> The comments suggestion is completely impractical for the size templates I work with, even with syntax highlighting.
>  
> That said, I just realized that it might make sense for <% %> to drop INDENT tokens as well, for the following reasons:
>  
> ·         Indentation doesn’t make sense for a single-line token.
> ·         If someone wanted to insert whitespace in the middle of a line in a single-line template, it wouldn’t be at the beginning of a line.
>  
> Sam
>  
> From: stringtemplate-interest-bounces at antlr.org [mailto:stringtemplate-interest-bounces at antlr.org] On Behalf Of Udo Borkowski
> Sent: Tuesday, April 05, 2011 10:10 PM
> To: Terence Parr
> Cc: stringtemplate-interest List
> Subject: Re: [stringtemplate-interest] "".."" won't work
>  
> Let's get back to the original issue: 
> we want to make templates more readable that currently packed in one line (to avoid newline output):
> Here's a simple example:
>  
> ruleRef(rule,label,elementIndex,args,scope) ::= <<
> <if(label)><label>=<endif><if(scope)><scope:delegateName()>.<endif><rule.name>(<args; separator=", ">);
> >> 
>  
> Do we really need a new feature to achieve this? 
> What about using stuff already implemented to improve readablity?
>  
> E.g. comments can be used to insert linebreaks that are visible in the template but not rendered:
>  
> ruleRef(rule,label,elementIndex,args,scope) ::= <<<!
> !><if(label)><!
> !><label>=<!
> !><endif><!
> !><if(scope)><!
> !><scope:delegateName()>.<!
> !><endif><!
> !><rule.name>(<args; separator=", ">);
> >> 
>  
> With a proper syntax highlighting (which makes comments very "light") it becomes even more readable:
>  
> ruleRef(rule,label,elementIndex,args,scope) ::= <<<!
> !><if(label)><!
> !><label>=<!
> !><endif><!
> !><if(scope)><!
> !><scope:delegateName()>.<!
> !><endif><!
> !><rule.name>(<args; separator=", ">);
> >> 
>  
> These comments can even be used to do indents, improving the readability again:
>  
> ruleRef(rule,label,elementIndex,args,scope) ::= <<<!
> !><if(label)><!
>     !><label>=<!
> !><endif><!
> !><if(scope)><!
>     !><scope:delegateName()>.<!
> !><endif><!
> !><rule.name>(<args; separator=", ">);
> >> 
> This final example looks very readable to me, even more readable than the template we would write with the suggested "newline eating" syntax:
> ruleRef(rule,label,elementIndex,args,scope) ::= <<<
> <if(label)>
> <label>=
> <endif>
> <if(scope)>
> <scope:delegateName()>.
> <endif>
> <rule.name>(<args; separator=", ">);
> >>> 
> Of cause this "comment formatting" involves a little more typing, but this can easily handled by any good editor (Ter: "... emacs is your friend ;)").
>  
> With this idea in mind, do we really need to add this "newline eating" feature? 
>  
> To me the benefit does not look that big. As I have not yet written any real long "one liners" I may not be the right person to judge this, so what do others think?
>  
> Implementing the "line eating" feature has quite its difficulties, as we noticed already. I have no doubt these issues can be solved, however I assume "StringTemplate's overall design simplicity" (Sam Harwell) will be bigger without it. 
>  
>  
> Udo
>  
> On 05.04.2011, at 18:31, Terence Parr wrote:
> 
> 
> yeah it was hassle flipping << >> to <% %> in Java.stg templates, though I'd need to insert [..] or whatever just the same.  still open for debate :)
> T
> On Apr 5, 2011, at 5:03 AM, Udo Borkowski wrote:
> 
> 
> Following this thread makes me think if extending the syntax through new template delimiters ("", """, <% or whatsoever) is really a good idea. 
>  
> I assume we run into less problems (conflict with old syntax, escape issues etc.) with just sticking to the old ones ("…"  and <<…>>) and just add the optional "[…]" template prefix, as already suggested earlier.
>  
> t() ::= […]<<
> .
> .
> .
> >> 
>  
> Udo
>  
>  
>  
> On 05.04.2011, at 06:15, Terence Parr wrote:
> 
> 
> oh right.  might work.
> Ter
> On Apr 4, 2011, at 8:06 PM, Sam Harwell wrote:
> 
> 
> If you chose % as your delimiter, it would still be fine. The template starts at <% and ends at %>.
>  
> <%%x%%>
>  
> Sam
>  
> From: Collin Fagan [mailto:collin.fagan at gmail.com] 
> Sent: Monday, April 04, 2011 9:29 PM
> To: Sam Harwell
> Cc: Terence Parr; stringtemplate-interest List
> Subject: Re: [stringtemplate-interest] "".."" won't work
>  
> I have no problem with <%...%> but that eliminates one character available as a valid delimiters right?
> 
> I can't set the starting and ending delimiters to '%' and have %%...%% can I?
> 
> Collin
> 
> On Mon, Apr 4, 2011 at 8:39 PM, Sam Harwell <sharwell at pixelminegames.com> wrote:
> If you want to emit the literal %> in the output, you can write it as %\>,
> using the existing escape sequence without breaking anything.
> 
> Sam
> 
> -----Original Message-----
> From: stringtemplate-interest-bounces at antlr.org
> [mailto:stringtemplate-interest-bounces at antlr.org] On Behalf Of Terence Parr
> Sent: Monday, April 04, 2011 8:07 PM
> To: stringtemplate-interest List
> Subject: Re: [stringtemplate-interest] "".."" won't work
> 
> 
> On Apr 4, 2011, at 6:05 PM, Sam Harwell wrote:
> 
> > I guess with <%..%>, the escape character is still \>?
> >
> > This should work fine.
> 
> Well, shouldn't need any escape really...should be \%?
> Ter
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