adds back structvarsexpr function

src/utils.jl

@@ -264,3 +264,30 @@ xmoment(c, g, n=1) = sum(g.X.^n.*c)/sum(c)
 
 "Compute the `n`th y-moment of `c` on the grid `g`."
 ymoment(c, g, n=1) = sum(g.Y.^n.*c)/sum(c)
+
+
+#TODO: delete structvarsexpr() but first make sure that GeophysicalFlows.jl does not require it
+"Returns an expression that defines a Composite Type of the AbstractVars variety."
+function structvarsexpr(name, physfields, transfields; vardims=2, parent=:AbstractVars, T=Float64, arraytype=:Array)
+  physexprs = [:($fld::$arraytype{T,$vardims}) for fld in physfields]
+  transexprs = [:($fld::$arraytype{Complex{T},$vardims}) for fld in transfields]
+  expr = :(struct $name{T} <: $parent; $(physexprs...); $(transexprs...); end)
+end
+"""
+    structvarsexpr(name, fieldspecs; parent=nothing)
+Returns an expression that defines a composite type whose fields are given by
+the name::type pairs specifed by the tuples in fieldspecs. The convention is
+name = fieldspecs[i][1] and type = fieldspecs[i][2] for the ith element of
+fieldspecs.
+"""
+function structvarsexpr(name, fieldspecs; parent=nothing)
+  # name = spec[1]; type = spec[2]
+  # example: fieldspecs[1] = (:u, Array{Float64,2})
+  fieldexprs = [ :( $(spec[1])::$(spec[2]) ) for spec in fieldspecs ]
+  if parent == nothing
+    expr = :(struct $name{T}; $(fieldexprs...); end)
+  else
+    expr = :(struct $name{T} <: $parent; $(fieldexprs...); end)
+  end
+  expr
+end