Variable as widget argument? (Sugarcube 2)

Comments

• richVIE

  January 2017

  If I understand you correctly, the Sugarcube 2 <<switch>>-macro might solve your problem, e.g.
  

  <<widget mywidget>>
      <<set $varToSet to $args[0]>>
      <<switch $varToSet>>
          <<case "red" >>
               <<set $red to 10>>
          <<case "blue" >>
               <<set $blue to 10>>
      <</switch>>
  <<endwidget>>
  

  
  (not tested, just a suggestion)
• Lux

  January 2017

  Hmm, but that would still require adding an additional switch case for each possible variable I want to use it with, right?
  
  In that case, I could also just make several widgets with slightly different names, which is my current workaround...
• TheMadExile

  January 2017

  First of all, you're not passing the variable properly. In SugarCube, there are a few ways to reference a variable in macros so that it may be modified, however, they all start with quoting the variable when you pass it in (just as you must with <<textbox>> for example). The reason you must quote the variable is found at the top of the macro library documentation (see: Passing a variable's name as an argument), to bypass automatic story variable substitution.
  
  Beyond that, you need to use the Stupid Print Trick™ to render a <<set>> with the name of the passed in variable on the left-hand side of the assignment expression.
  
  Try something like the following:

  <<widget "mywidget">><<print '<<set ' + $args[0] + ' to "something complicated">>'>><</widget>>
  
• Lux

  January 2017 edited January 2017

  I can't quite wrap my head around how that print trick works, but that did exactly what I needed. Thanks!
  
  EDIT: Actually I think I do now, the different types of quote marks confused me at first.
• TheMadExile

  January 2017

  As an explanation. Many of SugarCube's macros and other sections of the parser are pervasively recursive, so the <<set>>, rendered by the invocation of the <<print>>, is itself parsed.
  
  For example, assuming an invocation of the widget like:

  <<mywidget "$foo">>
  

  Yields a <<set>>, which is parsed, like the following:

  <<set $foo to "something complicated">>
  
• TheMadExile

  January 2017

  richVIE wrote: »

  <<widget mywidget>>
      <<set $varToSet to $args[0]>>
      <<switch $varToSet>>
          <<case "red" >>
               <<set $red to 10>>
          <<case "blue" >>
               <<set $blue to 10>>
      <</switch>>
  <<endwidget>>
  

  I believe we're done here, however, some commentary on your solution.

  1. If you're going to use a variable for what certainly seems to be a temporary use, then you should use an actual temporary variable—i.e. _varToSet instead of $varToSet—to keep the story history clean.
  2. An additional intermediate variable isn't necessary here in the first place—i.e. <<switch $args[0]>> is sufficient.