adding envs tagging/interpolation

envs/consts.go

@@ -12,22 +12,4 @@ var (
 
 var (
 	StructTagInterpolate string = "envsub"
-	StructTagPopulate    string = "envpop"
-)
-
-var (
-	defaultInterpolateOpts interpolateOpts = interpolateOpts{
-		noMapKey: false,
-		noMapVal: false,
-	}
-	// InterpolateOptNoMapKey is the equivalent of the struct tag `no_map_key` for Interpolate.
-	InterpolateOptNoMapKey optInterpolate = func(o *interpolateOpts) (err error) {
-		o.noMapKey = true
-		return
-	}
-	// InterpolateOptNoMapValue is the equivalent of the struct tag `no_map_value` for Interpolate.
-	InterpolateOptNoMapValue optInterpolate = func(o *interpolateOpts) (err error) {
-		o.noMapVal = true
-		return
-	}
 )