Initializations outside of newlist() cause a runtime error: Cannot read .[variableName

ID:2828180
 
Oct 22 2022, 1:30 am
Not a bug
BYOND Version:514
Operating System:Windows 10 Enterprise 64-bit
Web Browser:Chrome 106.0.0.0
Applies to:DM Language
Status: Not a bug
This is not a bug. It may be an incorrect use of syntax or a limitation in the software. For further discussion on the matter, please consult the BYOND forums.
Descriptive Problem Summary:

I am testing out initialization for a new library - and newList suggests the curly praces { } intializations can be used anywhere


This is the most common use of "modified types", but it is not specific to the newlist instruction. Anywhere a type value may be used in DM, it may be followed by a list of initializations. The general syntax for a modified types is:

path {var1 = val1; var2 = val2}


The code below compiles fine, but I get a funky runtime

Code Snippet (if applicable) to Reproduce Problem:
/datum/myDatum
    var/testVar = 10

/proc/main()
    var/datum/myDatum/listDatum
    var/list/listy = newlist(/datum/myDatum { testVar = 20 })
    for(listDatum in listy)
        world.log << listDatum.testVar
    
    var/datum/myDatum/testDatum = /datum/myDatum {testVar = 30}
    if(testDatum)
        world.log << "testDatum exists"
        world.log << testDatum.testVar


Expected Results:

I should be able to retrieve values from my object, as though I used new() and set the variable afterwards.

Actual Results:
Instead of the variable value, I get:
runtime error: Cannot read .testVar

Workarounds:

I can use newlist() and grab the object from the generated list, or I can use new() and set variables manually.
Oct 22 2022, 9:07 pm
You aren't newing my datum
/datum/myDatum
    var/testVar = 10

/proc/main()
    var/datum/myDatum/testDatum = new /datum/myDatum {testVar = 30}
    if(testDatum)
        world.log << "testDatum exists"
        world.log << testDatum.testVar

this for instance functions just fine
Oct 23 2022, 1:29 pm
Lummox JR resolved issue (Not a bug)