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

Sam Harwell sharwell at pixelminegames.com
Wed Apr 6 10:41:57 PDT 2011 

Looking through the ANTLR templates, do you see any cases where it's an
issue to throw out both NEWLINE and INDENT tokens coming from STLexer?
INDENT is any leading whitespace on a line.

I'm looking at my other large codegen project and I can't see any place
where I need that indent. All the "indented blocks" in my code are indented
within a regular <<...>> BIGSTRING.

Sam

-----Original Message-----
From: stringtemplate-interest-bounces at antlr.org
[mailto:stringtemplate-interest-bounces at antlr.org] On Behalf Of Terence Parr
Sent: Wednesday, April 06, 2011 12:36 PM
To: stringtemplate-interest List
Subject: Re: [stringtemplate-interest] "".."" won't work

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><ru
> le.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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