Policy definition DSL syntax (LacLang)

• Data types:

bool := true | false

string := "any string"

bytes := 'bytes with 0x prefix'

address := address with 0x prefix

number := any unsigned decimal number fitting uint256

• Mutability keywords:

constant - declares constant (constant bytes = '0xdeadbeef';)

var - declares variable (variables must not be initialized!) (var address proxyAddress;) Variables can be injected - meaning their value is meant to be replaced with the value of a corresponding attribute on some kind of an interceptor (e.g. backend). Then the inject("<name_of_the_attribute>") syntax must be used (var inject("IS_PRODUCTION") bool mutateState;)

• Other keywords:

artifact - declares artifact via it's address literal (no reference yet) (artifact dayOrNight = 0x95222290DD7278Aa3Ddd389Cc1E1d165CC4BAfe5)

instance <return type> * of <artifact> takes ([<constants, vars, instances>]) /*OPTIONAL:*/ with ([<constants>]); - declares instance, that implements artifact (can be literal or artifact reference), that consumes in exec "takes ..." and in init "with ..."

instance bytes codedImage of imageCoder takes (imageInBmp, resolutionInstanceOutput) with (codec);

• Statements:

evaluate <instance name that returns bool> - defines the root of the policy = boolean! instance that will return as a policy evaluation result evaluate finalInstance;

All constuctions end with semicolon ; Pay allention to quotes Only boolean artifact can be evaluated Only single string comments using //

Valid example:

var inject("is_dev") bool boolVar;
var bytes spare;

constant number init1 = 0;
constant bool bool1 = true; 
constant number num1 = 1;
constant address addr1 = 0xD9e88d1d18d8Cf3a17e97af9F017Ef8760dee583; // random
constant string str1 = "lang";
constant bytes bts1 = '0xdeadbeef';

artifact art1 = 0x6768008f6c2Ac94F9D65533D13A974b376495c7b; // random
artifact art2 = 0xB60B02062d1256A79C81A061a9277e84ffbB0Ff7; // random

instance number inst1 of art1 takes (num1, str1, "here I am") with (init1, bts1, bool1);
instance bool inst2 of art2 takes (inst1, addr1, boolVar, bts1, inst1, bool1);
instance bool inst3 of art2 takes (inst1, inst2) with ("initialize me", '0xd00d', 0xB60B02062d1256A79C81A061a9277e84ffbB0Ff7);

evaluate inst2;