==========
lovely tal
==========

the lovely tal package is meant to contain new tal:expressions



TextFormatter
-------------

   option replace: takes a list of tuples, which characters or strings should be
                   replaced by what, e.g. 
                   "replace python:[(origChar, repChar), (origChar2, repChar2), ...]"
                   
   option allow:   takes a list of html-tags which shall be allowed in the string
                   e.g. "allow python:['a', 'br', 'ul', 'li']"
                   if this option is not set, the string is restricted to
                   contain no html-tags, therefor the < and > are replaced 
                   by &lt;, &gt;
                   
   option allow-all: allow all html-tags in the string
   					 e. g. "allow-all: 'True'"
   
   option break-string: force the string to break after a given number of characters
   						e.g. "break-string python:25" breaks the string after 
   						a sequence of 25 characters not containing a linebreak
   						
   option cut: cuts a string to the given length
   option attach: works only together with option 'cut', 
                  attaches the given string to the expression, if this is longer than
                  number of characters given in option 'cut'
   						
<span tal:define="replace python:[('\n', '<br />')];
                  allow python:['a', 'br'];
                  break-string python:25;
                  cut python 25;
                  attach '...'"
      tal:content="structure textFormatter: view/description">Description</span>
      
      

Lets see if the TextFormatter does what we want him to.

We have to fake a context object to call the textformatter

  >>> class Context(object):
  ...     vars = {}
  ...     def __init__(self, vars):
  ...         self.vars = vars

  >>> from lovely.tal.textformatter import TextFormatter
  >>> from zope.tales.expressions import simpleTraverse
  >>> from zope.app.pagetemplate.engine import TrustedZopeEngine
  >>> tf = TextFormatter('textFormatter', 'view/title', TrustedZopeEngine(), simpleTraverse)
  >>> context = Context({})
  >>> tf._doFormat('<a href="#" name="foolink">foolink</a>', context)
  '&lt;a href="#" name="foolink"&gt;foolink&lt;/a&gt;'
  >>> tf._doFormat('<a href="#" name="foolink">foolink</a><br /><form action="."><input type="text" /></form>', context)
  '&lt;a href="#" name="foolink"&gt;foolink&lt;/a&gt;&lt;br /&gt;&lt;form action="."&gt;&lt;input type="text" /&gt;&lt;/form&gt;'
  
if we provide an empty context, the textformatter translates all html-tags to &lt; &gt;

Option 'allow'
==============

We can allow certain html-tags in the text

  >>> context = Context({'allow':['a']})
  >>> tf._doFormat('<a href="#" name="foolink">foolink</a><br /><form action="."><input type="text" /></form>', context)
  '<a href="#" name="foolink">foolink</a>&lt;br /&gt;&lt;form action="."&gt;&lt;input type="text" /&gt;&lt;/form&gt;'
  
  >>> context = Context({'allow':['a', 'br']})
  >>> tf._doFormat('<a href="#" name="foolink">foolink</a><br /><form action="."><input type="text" /></form>', context)
  '<a href="#" name="foolink">foolink</a><br />&lt;form action="."&gt;&lt;input type="text" /&gt;&lt;/form&gt;'
  
  >>> context = Context({'allow':['a', 'br', 'form']})
  >>> tf._doFormat('<a href="#" name="foolink">foolink</a><br /><form action="."><input type="text" /></form>', context)
  '<a href="#" name="foolink">foolink</a><br /><form action=".">&lt;input type="text" /&gt;</form>'

In the above example, still the content of the form tag is translated 
 
Lets try to write dirty html

  >>> context = Context({'allow':['a', 'br', 'form']})
  >>> tf._doFormat('< a href="#" name="foolink">foolink</ a><br/>< form action="."><input type="text" /></form >', context)
  '&lt; a href="#" name="foolink"&gt;foolink&lt;/ a&gt;<br/>&lt; form action="."&gt;&lt;input type="text" /&gt;&lt;/form &gt;'

Since the a-tag and the form-tag are not valid html, they are translated, although we declared them to be allowed  
We get the same result if we do not allow them

  >>> context = Context({'allow':['br']})
  >>> tf._doFormat('< a href="#" name="foolink">foolink</ a><br/>< form action="."><input type="text" /></form >', context)
  '&lt; a href="#" name="foolink"&gt;foolink&lt;/ a&gt;<br/>&lt; form action="."&gt;&lt;input type="text" /&gt;&lt;/form &gt;'


Option 'allow-all'
==================
 
We can allow all html-tags

  >>> context = Context({'allow-all':True})
  >>> tf._doFormat('<a href="#" name="foolink">foolink</a><br /><form action="."><input type="text" /></form>', context)
  '<a href="#" name="foolink">foolink</a><br /><form action="."><input type="text" /></form>'


Option 'replace'
================

We can replace characters or strings, e.g. we would like to replace the '\n' character by '<br />'
to display the text properly.

  >>> context = Context({'replace':[('\n', '<br />')]})
  >>> tf._doFormat('das Schwein, \n das aus der Wueste kam', context)
  'das Schwein, <br /> das aus der Wueste kam'
  
we can also replace strings

  >>> context = Context({'replace':[('\n', '<br />'), ('Schwein', 'Kamel')]})
  >>> tf._doFormat('das Schwein, \n das aus der Wueste kam', context)
  'das Kamel, <br /> das aus der Wueste kam'
 

Option 'break-string'
=====================

Another option is to break strings after a given number of characters n, in case there
was no break or '\s' in the last n characters.

  >>> context = Context({'break-string':8})
  >>> tf._doFormat('das Schwein, das aus der Wueste kam', context)
  'das<br />Schwein,<br />das aus<br />der<br />Wueste<br />kam'
  
  >>> context = Context({'break-string':8})
  >>> tf._doFormat('ein superlangerstring mit ein paar kurzen strings', context)
  'ein<br />superlan<br />gerstrin<br />g mit<br />ein paar<br />kurzen<br />strings'

Also multi line text works.

  >>> context = Context({'break-string':40})
  >>> res = tf._doFormat("""
  ... ein superlangerstring mit ein paar kurzen strings.
  ... 
  ... - another line
  ... 
  ... - another long string which needs to break
  ... and this needs to break twice because it is longer than 80 characters, hopefully it works
  ... """, context)
  >>> print res.replace('<br />', '\n')
  <BLANKLINE>
  ein superlangerstring mit ein paar
  kurzen strings.
  <BLANKLINE>
  - another line
  <BLANKLINE>
  - another long string which needs to
  break
  and this needs to break twice because it
  is longer than 80 characters, hopefully
  it works
  <BLANKLINE>

  >>> context = Context({'break-string':20, 'allow':['br']})
  >>> text = u'eins zwei drei vier fuenf sechs sieben,<br />'
  >>> text += u'in der Schule wird geschrieben,<br />'
  >>> text += u'in der Schule wird gelacht,<br />'
  >>> text += u'bis der Lehrer pitschpatsch macht!'
  >>> res = tf._doFormat(text, context)
  >>> print res.replace('<br />', '\n')
  eins zwei drei vier
  fuenf sechs sieben,
  in der Schule wird
  geschrieben,
  in der Schule wird
  gelacht,
  bis der Lehrer
  pitschpatsch macht!

the formatter considers tags as not to be part of the text, that means that
breaks aren't made inside tags (<...>)

  >>> context = Context({'break-string':8, 'allow':['a']})
  >>> tf._doFormat('working at <a href="www.lovelysystems.com" name="lovelysystems">lovelysystems</a> is great!', context)
  'working<br />at<br /><a href="www.lovelysystems.com" name="lovelysystems">lovelysy<br />stems</a> is<br />great!'
  

Option 'cut'
============  

We can also cut strings to a given length

  >>> context = Context({'cut':20})
  >>> rendered = tf._doFormat('ein superlangerstring mit ein paar kurzen strings', context)
  >>> len(rendered) == 20
  True
  

Option 'attach'
===============

and attach a string to the expression

  >>> context = Context({'cut':20, 'attach':'...'})
  >>> tf._doFormat('ein superlangerstring mit ein paar kurzen strings', context)
  'ein superlangerstrin...'
 
