Distinct Attribute

Distinct Attributes are used to identify a token.

A distinct attribute is defined by setting distinct to true.

<attribute name="vin" distinct="true">

If there is only one distinct attribute in a token, then the number of unique values of this attribute determins how many token instances are there.

Note: Each Token is identified by a attribute-value pair where the attribute has to be a distinct attribute. See more in Token Identifier

If there is no distinct attribute defined in a Token, TokenScript Engine takes a default value ownerAddress=${ownerAddress} as its Token Identifier.

A Car Ownership Token

In this example, which is part of a TokenScript that defines a Car Ownership Toke. Vehicle Identification Number ("vin") is an attribute that identifies a car:

  <ts:attribute name="vin" **distinct="true"**>
      <ts:string xml:lang="en">Vehicle Identification Number</ts:string>
      <ethereum:call function="getCars" contract="CarOwnership"/>

Since VIN is a distinct token, each distinct values of this attribute is used to create a distinct token. So, let's say that the function getCars() in this example returns an array of two values:

"KL3TA48E9EB541191", "KL3TA48E9EB541192"

Then, the TokenScript engine should interpret that there are 2Car Tokens, identified the following two Token Identifiers:


Both are instances of the Car Token. If the TokenScript engine is running in a user's wallet, it would render two distinct cars.


The following code defines a distinct attribute called tokenId.

<ts:attribute name="tokenId" **distinct="true"\>**
    <ethereum:call function="balanceOf" contract="EntryToken">
        <ts:uint256 ref="ownerAddress"></ts:uint256>

If the smart contract returns 2 values for it:

  • 0x59a7a9fd49fabd07c0f8566ae4be96fcf20be5e1
  • 0xd915c8AD3241F459a45AdcBBF8af42caA561A154

then the TokenScript engine identifies 2 tokens, each identified with:

  • tokenId=0x59a7a9fd49fabd07c0f8566ae4be96fcf20be5e1
  • tokenId=0xd915c8AD3241F459a45AdcBBF8af42caA561A154

In fact, this attribute can be found in all ERC721 tokens, as ERC721 requires an attribute tokenID to identify a token. However, such a design may not suit other tokens who doesn't benefit from being shoe-horned into ERC721.

Parent topic:Features implemented

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