[dev-context] Stretch charatcers

[Hans Hagen]

On 12/3/2012 10:09 AM, Wolfgang Schuster wrote:
>
> Am 02.12.2012 um 23:18 schrieb Hans Hagen <pragma at wxs.nl>:
>
>> On 12/2/2012 4:31 PM, Wolfgang Schuster wrote:
>>> Hi,
>>>
>>> how can I write the following two lines with Lua, I saw in supp-box.lua a few example how to loop through the characters but I don’t know how I can add glue between them.
>>>
>>> \starttext
>>>
>>> \ruledhbox to 6cm{\processtokens{\hfil }{\hfil\hfil}{\hfil }{}{WORD}}
>>>
>>> \ruledhbox to 6cm{\processtokens{\relax}{\hfil\hfil}{\relax}{}{WORD}}
>>>
>>> \def\HFILLED#1{\hfil#1\hfil}
>>>
>>> \ruledhbox to 6cm{\applytocharacters\HFILLED{WORD}}
>>> \ruledhbox to 6cm{\hfilneg\applytocharacters\HFILLED{WORD}\hfilneg}
>>>
>>> \stoptext
>>
>> \startluacode
>> function commands.ws_hfilled(str)
>>     context.hfil()
>>     for c in string.utfcharacters(str) do
>>         context(c)
>>         context.hfil()
>>     end
>> end
>> \stopluacode
>>
>> \enabletrackers[context.trace]
>>
>> \def\HFILLED#1{\ctxcommand{ws_hfilled("#1")}}
>>
>> \ruledhbox to 6cm{\HFILLED{WORD}}
>> \ruledhbox to 6cm{\hfilneg\HFILLED{WORD}\hfilneg}
>
> This does the trick but can I check for the last char without the additional check (if n == string.utflength(str)) in the example below?
>
> \startluacode
> function commands.ws_hfilled(str,margin)
>      local n = 0
>      if margin then context.hfil() end
>      for c in string.utfcharacters(str) do
>          n = n + 1
>          context(c)
>          if n == string.utflength(str) then
>              if margin then context.hfil() end
>          else
>              context.hfil()
>          end
>      end
> end
> \stopluacode
>
> \starttext
> \ruledhbox to 6cm{\ctxlua{commands.ws_hfilled("WORD")}}
> \ruledhbox to 6cm{\ctxlua{commands.ws_hfilled("WORD",true)}}
> \stoptext

easier:

\startluacode
function commands.ws_hfilled(str,margin)
     local done = false
     for c in string.utfcharacters(str) do
         if done or margin then
             context.hfil()
         else
             done = true
         end
         context(c)
     end
     if margin then
         context.hfil()
     end
end
\stopluacode

\starttext
\ruledhbox to 6cm{\ctxlua{commands.ws_hfilled("WORD")}}
\ruledhbox to 6cm{\ctxlua{commands.ws_hfilled("WORD",true)}}
\stoptext


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