codes in if statements are not parsed correctly

BangL commented 8 years ago

example:

if (isNull _bla && {_bla != ""}) then {};

in this example one if-condition is in {}-brackets, which will lead into this condition not beeing checked unless the other one was true. - this is a wonderful and proper way of preventing NPE's without having to make two nested if's, but sadly this is marked as invalid.

kayler-renslow commented 8 years ago

This doesn't make any sense. Aren't these two the same? if (isNull _bla && {_bla != ""}) then {}; if (isNull _bla && _bla != "") then {}; I also don't know what "NPE" means.

BangL commented 8 years ago

NPE is Null Pointer Exception

the example was not the best actually, a better example would be like: if (isNil "_bla" && {_bla != ""}) then {};

imagine a case where _bla actually IS nil...

if you would write: if (isNil "_bla" && _bla != "") then {}; it would crash at _bla != "" because _bla is nil, therefore it cant be parsed. ...arma checks the second statement, even if the first was false already. ( the "&&" cant be true in the end anyways) so, to work around that problem, you can use code-brackets. this tells the parser to only check the statement if "needed" (depending on the used logical operators) and so you would not get an "NPE" at _bla != "" anymore

BangL commented 8 years ago

its like a mini-if in an if. :D

kayler-renslow commented 8 years ago

That's kind of weird that the scripting engine doesn't allow short circuiting (check up until one condition is false). I'll put in the change right now.

This would also make for a nice code inspection... I think I'll make it one.

kayler-renslow commented 8 years ago

this has been fixed for next version

X39 commented 8 years ago

the <bool> && <code> syntax is for lazy evaluation

it is still recommended to nest the later &&s in the code block further as the script engine still will parse everything otherwise

reason for this btw. is because the script engine will interpret it like so:

&& which itself again is an expression --> `false && false && false` pretty much just means one thing for the script engine: && where either the LArg or the RArg is the same again lazy evaluation just is a hacky way to prevent the execution at all

BangL commented 8 years ago

a hacky but valid and working way. the only important question is: should it be marked as a mistake or not. - it should not, because its not a mistake. coding taste does not matter here.

2016-07-20 16:34 GMT+02:00 Marco Silipo notifications@github.com:

the && syntax is for lazy evaluation
it is still recommended to nest the later &&s in the code block further as the script engine still will parse everything otherwise reason for this btw. is because the script engine will interpret it like so: && which itself again is an expression --> false && false && false pretty much just means one thing for the script engine: && where either the LArg or the RArg is the same again lazy evaluation just is a hacky way to prevent the execution at all — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/kayler-renslow/arma-intellij-plugin/issues/14#issuecomment-233968120, or mute the thread https://github.com/notifications/unsubscribe-auth/AAhp6CSxzKAQ44QQxVpeSXFiwIseGWFJks5qXjISgaJpZM4JKXeg .



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kayler-renslow / arma-intellij-plugin

codes in if statements are not parsed correctly #14