interpolation 'enhancement'

["Geir Magnusson Jr." <ge...@optonline.net>]

For those of you that ignore commit diff-gibberish,  last night I
checked in changes to the parser and the AST code to support
single-quote string literals ( '$foo' ) in VTL. Unlike their
double-quote siblings ( "$foo" ) they won't be interpolated.  Think
'Perl' here.  This was brought up and discussed a while back so I don't
think anyone will be upset, surprised or diappointed, but if so, say so.

To review :

1) There is a property stringliterals.interpolate, default true, that
controls interpolation of string literals.  

2) When true (the default), any string literal contained in double-quote
characters ( " ) will be parsed and rendered.  This can be as simple as
doing string concatenation :

  #set( $directoryRoot = "www" )
  #set( $templateName = "index.vm" )
  #set( $template = "$directoryRoot/$templateName" )

  $template  - renders as -> www/index.vm

or invoking directives and Velocimacros :

  #set( $templateName = "index.vm" )
  #set( $template = "#if($root) #makedirectorypath( $root $template )
#else default/$templateName #end" )

  and with $root not defined in the context :

  $template - renders as ->  default/index.vm

   where #makedirectorypath() is some Velocimacro.

See interpolation.vm in test/templates for more [wacky] examples.

3) When the string literal is bounded by single-quote characters ( ' )
no interpolation occurs.

  #set( $blargh = '$foo' )

  $blargh - renders ->  $foo

As always, comments, discussion, etc...

geir

P.S.  Anyone think that the situational pun in the Subject was funny? :)

-- 
Geir Magnusson Jr.                               geirm@optonline.com
Velocity : it's not just a good idea. It should be the law.
http://jakarta.apache.org/velocity

Re: interpolation 'enhancement'

[Daniel Rall <dl...@finemaltcoding.com>]

"Geir Magnusson Jr." <ge...@optonline.net> writes:

> For those of you that ignore commit diff-gibberish,  last night I
> checked in changes to the parser and the AST code to support
> single-quote string literals ( '$foo' ) in VTL. Unlike their
> double-quote siblings ( "$foo" ) they won't be interpolated.  Think
> 'Perl' here.  This was brought up and discussed a while back so I don't
> think anyone will be upset, surprised or diappointed, but if so, say so.

+1

Daniel

Re: interpolation 'enhancement'

["Geir Magnusson Jr." <ge...@optonline.net>]

Christoph Reck wrote:
> 
> What happens with a $reference within single quotes inside of
> another string, e.g.:
>   <a href="javascript:doFileAction('$command','$name')">$command</a>
> Will $command and $name be expanded.

Yes, as you expect,  because they aren't technically VTL string
literals.  A VTL string literal is only found as :

1) the RHS of a #set() directive
2) an arg to a directive or a VM
3) an arg to a method of a reference object such as $foo.bar("woogie")

So the template :

#set($command="foo")
#set($name="woogie")
<a href="javascript:doFileAction('$command','$name')">$command</a>

outputs

<a href="javascript:doFileAction('foo','woogie')">foo</a>

like you expect, hope and wish for.

> The behaviour I would expect is like in a (c)shell:
>   echo "'$HOME'"
> does an expand; whereas
>   echo '$HOME'
> does not.

For the template :

#set($command="foo")
#set($e = "$command")
#set($f = "'$command'")
#set($g = '$command')
$e
$f
$g

you get :

foo
'foo'
$command

Which I think is what you want.

geir

> 
> :) Christoph
> 
> "Geir Magnusson Jr." wrote:
> >
> > For those of you that ignore commit diff-gibberish,  last night I
> > checked in changes to the parser and the AST code to support
> > single-quote string literals ( '$foo' ) in VTL. Unlike their
> > double-quote siblings ( "$foo" ) they won't be interpolated.  Think
> > 'Perl' here.  This was brought up and discussed a while back so I don't
> > think anyone will be upset, surprised or diappointed, but if so, say so.

-- 
Geir Magnusson Jr.                               geirm@optonline.com
Velocity : it's not just a good idea. It should be the law.
http://jakarta.apache.org/velocity

Re: interpolation 'enhancement'

[Christoph Reck <Ch...@dlr.de>]

What happens with a $reference within single quotes inside of
another string, e.g.:
  <a href="javascript:doFileAction('$command','$name')">$command</a>
Will $command and $name be expanded. 

The behaviour I would expect is like in a (c)shell:
  echo "'$HOME'"
does an expand; whereas
  echo '$HOME'
does not.

:) Christoph

"Geir Magnusson Jr." wrote:
> 
> For those of you that ignore commit diff-gibberish,  last night I
> checked in changes to the parser and the AST code to support
> single-quote string literals ( '$foo' ) in VTL. Unlike their
> double-quote siblings ( "$foo" ) they won't be interpolated.  Think
> 'Perl' here.  This was brought up and discussed a while back so I don't
> think anyone will be upset, surprised or diappointed, but if so, say so.

Re: interpolation 'enhancement'

[Daniel Rall <dl...@finemaltcoding.com>]

"Geir Magnusson Jr." <ge...@optonline.net> writes:

> For those of you that ignore commit diff-gibberish,  last night I
> checked in changes to the parser and the AST code to support
> single-quote string literals ( '$foo' ) in VTL. Unlike their
> double-quote siblings ( "$foo" ) they won't be interpolated.  Think
> 'Perl' here.  This was brought up and discussed a while back so I don't
> think anyone will be upset, surprised or diappointed, but if so, say so.

+1

Daniel