Problem with if and either

Comments

• Gordon

  January 2015

  progress!!  - why do I often find that as soon as I have almost given up and asked for help, I get an idea?
  
  Part of my problem is that I assumed that a non-zero value in a variable will evaluate to true, which I found when trying the Harlowe example on anonymous hooks:
  {
  (set: $heartbeat to  10)  (set: $breathing to  1)
  (set: $alive to $heartbeat > 0 and $breathing)
  }
  You find yourself in a dark, $alive[spooky ]part of the dungeon.
  If you run this, the output shows the actual $alive variable:
  You find yourself in a dark, 1spooky part of the dungeon.
  
  If I change my original script to use true/false instead of numbers, like so:
  (set: $Dest1 to true)
  (set: $Dest2 to false) <!--i.e. we don't expect to see Dest2 as an action-->
  (set: $Dest3 to true)
  and the part that creates a list of actions like so:
  (set: $Actions to "")
  (if:  $Dest1 ) [(set: $Actions to $Actions + " action1" )]
  (if:  $Dest2 ) [(set: $Actions to $Actions + " action2" )]
  (if:  $Dest3 ) [(set: $Actions to $Actions + " action3" )]
  
  then the $actions variable gets "action1 action3" as required.
  
  I still haven't had any success in passing the $actions variable to the (either: ) macro, but at least I think I might be able to do it in the way the $alive example showed... provided I can use actual passage links for the actions. I'll try that next.
  Something like this:
  Possible actions are: $Dest1[runlink ] $Dest2[jumplink ] $Dest3[swimlink]
  
  Sorry if having asked the question I've had anyone go off on a wild goose chase
  
  
• greyelf

  January 2015

  edited: It is good that you worked out the first issue yourself. LOL
  
  1. The first issue is that you are missing the [ and ] symbols from your (if:) macros:

  
wrong - (if: $Dest1 is 0 ) (set: $Actions to $Actions + " action1" )

right - (if: $Dest1 is 0 )[(set: $Actions to $Actions + " action1" )]


  2. The second issue is that you are mixing Datatypes, you're passing a single String value to the (either:) macro when it is expecting a List of String values.
  eg.
  Your $Actions variable (once your (if:) macros are fixed) contains a String value: " action1 action3" so when Harlowe processes your (either: $Actions ) it is converted to (either: " action1 action3") but the result you really want is (either: "action1","action3").
  
  Unfortunately it is not enough to just add comas to your String so what you need to do is change your $Actions variable from storing a String to storing an Array.
  (note: The Harlowe documentation suggests using it when modifying the value of a variable)

  
(set: $Actions to (a:))
(if: $Dest1 is 0 )[(set: $Actions to it + (a: "action1"))]
(if: $Dest2 is 0 )[(set: $Actions to it + (a: "action2"))]
(if: $Dest3 is 0 )[(set: $Actions to it + (a: "action3"))]


  Because your variable is now an Array you have to use the "spread" operator (three full stops) when passing the variable to the (either:) macro

  
(set: $ZZ to (either: ...$Actions ) ) <!--should now work! -->


  So your code would now look like the following:

  
Test to see if I can make "ifs" and "Either" work!
{
(set: $Dest1 to 0)
(set: $Dest2 to 10) <!--i.e. we don't expect to see Dest2 as an available action-->
(set: $Dest3 to 0)
}
variables Dest1= $Dest1; Dest2= $Dest2; Dest3= $Dest3
{
(set: $Actions to (a:))
(if: $Dest1 is 0 )[(set: $Actions to it + (a: "action1"))]
(if: $Dest2 is 0 )[(set: $Actions to it + (a: "action2"))]
(if: $Dest3 is 0 )[(set: $Actions to it + (a: "action3"))]
}
these are the possible actions (we should not see Action2): $Actions
{
(set: $YY to (either: "action1","action2","action3")) <!--this works-->
(set: $ZZ to (either: ...$Actions ) ) <!--this should now work -->
}
Action selected from list of strings:<br> $YY
Action selected from variable with list of strings:<br> $ZZ

• L

  January 2015

  Gordon wrote:

  
  Part of my problem is that I assumed that a non-zero value in a variable will evaluate to true, which I found when trying the Harlowe example on anonymous hooks:
  {
  (set: $heartbeat to  10)  (set: $breathing to  1)
  (set: $alive to $heartbeat > 0 and $breathing)
  }
  You find yourself in a dark, $alive[spooky ]part of the dungeon.
  If you run this, the output shows the actual $alive variable:
  You find yourself in a dark, 1spooky part of the dungeon.
  

  Hmm, this raises a good point: there should really be an error when "and" is used to join non-boolean expressions, like the number 1.
• Gordon

  January 2015

  thanks for the help about the either problem - it works a treat.( I've spent too long playing with loosely typed languages!) It'll be fun explaining that to my group of 10 year olds, but they are a clever bunch.