[stringtemplate-interest] Output string lengths..

[John Snyders]

Output string lengths..Here is a crazy thought.

If you could iterate over the characters in a string then the template could
do the padding.
I created a function "chars" which returns an iterator for its string
argument.
For example
  $s1$
  $chars(s1); separator="-"$
will produce
  SOMETHING
  S-O-M-E-T-H-I-N-G
when s1="SOMETHING"

With these attributes added in the controller:
  test.setAttribute("s1", "SOMETHING");
  test.setAttribute("s2", "NOTHING");
  test.setAttribute("space40", "                                        ");

This template
  |$chars(s1),chars(space40): { ch, sp | $ch;null={$sp$}$}$|
  |$chars(s2),chars(space40): { ch, sp | $ch;null={$sp$}$}$|

produces this output
  |SOMETHING                               |
  |NOTHING                                 |
(forgive the proportional font of this email)

Does the chars function have any other use? Well it could be used to do what
the CSS pseudo element ":first-letter" does. For example:
  <span class="fancy">$first(chars(s1))$</span>$rest(chars(s1))$
produces:
  <span class="fancy">S</span>OMETHING

This gives some stylistic control over individual letters to the template.

What do people think, is the chars function useful?
As for padding, I'm not sure I like this solution better than the pad
option.

-John

Here is the code just incase someone wants to play with this:

Added to ASTExpr.java
private static class StringIterator implements Iterator
{
 private String str;
 private int index;
 public StringIterator(String str) {
  this.str = str;
  index = 0;
 }
 public boolean hasNext() {
  return index < str.length();
 }

 public Object next() {
  String next = String.valueOf(str.charAt(index));
  index++;
  return next;
 }

 public void remove() {
  throw new UnsupportedOperationException();
 }

}

public Object chars(Object attribute) {
 if ( attribute==null ) {
  return null;
 }
 Object chars = null;
 if ( attribute instanceof String ) {
  String str = (String)attribute;
  chars = new StringIterator(str);
 }
 else if ( attribute instanceof StringTemplate )
 {
    StringTemplate st = (StringTemplate)attribute;
    String str = st.toString();
    chars = new StringIterator(str);
 }

 return chars;
}

Add this to eval.g near trunc
      | "chars" a=singleFunctionArg {value=chunk.chars(a);}

Add this to action.g near trunc
     |   "chars"





-----Original Message-----
From: stringtemplate-interest-bounces at antlr.org
[mailto:stringtemplate-interest-bounces at antlr.org]On Behalf Of Hill, Robert
Sent: Wednesday, November 22, 2006 2:27 AM
To: StringTemplate
Subject: [stringtemplate-interest] Output string lengths..


  Is there anyway I can make each string in a list be rendered at a minimum
length?
  Id like some things to line up in columns, and want to avoid any sort of
formatting occuring in the code, before I stuff the strings into the
templates.

  Is this a job for a custom format renderer, or is there a way to do this
directly within string template?

  Ta!

  Regards,

  Rob

  Robert Hill
  Information Engineer
  E       UKIMEA DWP ACU, Hallamshire Business Park, 100 Napier St,
Sheffield. S11 8HD
  email:  rhill03 at eds.com
  Office: +44 114 291 1928
  Mobile: +44 7903 185 516


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