CODEWITHSUNDEEP
ti-basicti-nspire
Maxim Podolski
Maxim Podolski

Reputation: 11

In TI-BASIC, how do I display the Variable Name given only the variable?

I'm creating a function that displays a lot of variables with the format Variable + Variable Name.

Define LibPub out(list)=
Func
Local X
for x,1,dim(list)
  list[x]->name // How can I get the variable name here?
  Disp name+list[x]
EndFor
Return 1
EndFunc

Upvotes: 1

Views: 384

Answers (2)

Meepo
Meepo

Reputation: 368

This will be memory intensive, but you could keep a string of variable names, and separate each name by some number of characters and get a substring based on the index of the variable in the list that you want to get. For instance, say you want to access index zero, then you take a substring starting at (index of variable * length of variable name, indexofvariable *length + length+1). The string will be like this: say you had the variables foo, bas, random, impetus the string will be stored like so: "foo bas random impetus "

Upvotes: 0

soegaard
soegaard

Reputation: 31147

Given a list value, there is no way to find its name.

Consider this example:

a:={1,2,3,4}
b:=a               ; this stores {1,2,3,4} in b
out(b)

Line 1: First the value {1,2,3,4} is created. Then an variable with name a is created and its value is set to {1,2,3,4}.

Line 2: The expression a is evaluated; the result is {1,2,3,4}. A new variable with the name b is created and its value is set to `{1,2,3,4}.

Line 3: The expression b is evaluated. The variable reference looks up what value is stored in b. The result is {1,2,3,4}. This value is then passed to the function out.

The function out receives the value {1,2,3,4}. Given the value, there is no way of knowing whether the value happened to be stored in a variable. Here the value is stored in both a and b.

However we can also look at out({1,1,1,1}+{0,2,3,4}).

The system will evaluate {1,1,1,1}+{0,2,3,4} and get {1,2,3,4}. Then out is called. The value out received the result of an expression, but an equivalent value happens to be stored in a and b. This means that the values doesn't have a name.

In general: Variables have a name and a value. Values don't have names.

If you need to print a name, then look into strings.

Upvotes: 1

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