Shader setting integer

I want to be able to tell a shader what order the object I'm drawing is in. I get parser error on line 4.

  Shader "testShader" {
         Properties {
             _Color ("Main Color", Color) = (.5,.5,.5,.5)
             layer("Layer",int)= 1000   <<< line 4
         }
         
         SubShader {
             Ztest Always
             Tags(Queue=layer)
             Pass {    
                  Material {
                     Diffuse [_Color]
                 }               
             }
     
         }
     }