Using ternary operator to retrieve PlayerInfo gives error

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The Zombie Killer
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Using ternary operator to retrieve PlayerInfo gives error

Post by The Zombie Killer »

Whilst working on adding custom cheats via ZScript, I encountered a rather puzzling issue:

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let player = pn != -1 ? players[pn] : players[consoleplayer];
let mo     = player.mo;

// the below works, the above gives a script error
//let mo     = pn != -1 ? players[pn].mo : players[consoleplayer].mo;
//let player = mo.player;  
See zscript.zsc, line 17
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Graf Zahl
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Re: Using ternary operator to retrieve PlayerInfo gives erro

Post by Graf Zahl »

The 'issue' is that 'players' is an array of structs and the ternary operator cannot deal with non-scalars. In this particular case the internal conversion to a pointer type occurs too late. Sadly this is not something easily fixed with how the entire system works.

Better do this:

Code: Select all

let player = players[pn != -1? pn : consoleplayer];
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The Zombie Killer
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Re: Using ternary operator to retrieve PlayerInfo gives erro

Post by The Zombie Killer »

Doing that gives me another error: "Cannot initialize non-scalar variable player here"
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Graf Zahl
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Re: Using ternary operator to retrieve PlayerInfo gives erro

Post by Graf Zahl »

Damn. Then you have to give it an explicit type (i.e. replace 'let' with 'PlayerInfo'. There's a few issues in the entire system with global instance variables of native struct types because to the compiler their type is ambiguous.
I wish this had gone differently but when discussing these issues with Randi nothing came out of it. The mere idea of types that can both be used by value and by reference never was part of ZScript's design, although a necessity, so it led to some not so nice problems.
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The Zombie Killer
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Joined: Thu Jul 14, 2011 12:06 am
Location: Gold Coast, Queensland, Australia

Re: Using ternary operator to retrieve PlayerInfo gives erro

Post by The Zombie Killer »

That fixed it. I guess you can consider this bug closed then.

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