Initial implementation

Author: tkf

Project.toml

@@ -3,6 +3,9 @@ uuid = "b9860ae5-e623-471e-878b-f6a53c775ea6"
 authors = ["Takafumi Arakaki <aka.tkf@gmail.com> and contributors"]
 version = "0.1.0"
 
+[deps]
+ContextVariablesX = "6add18c4-b38d-439d-96f6-d6bc489c04c5"
+
 [compat]
 julia = "1"
 

src/FLoopsBase.jl

@@ -1,5 +1,12 @@
 module FLoopsBase
 
-# Write your package code here.
+using ContextVariablesX
+@contextvar EXTRA_STATE_VARIABLES::Union{Vector{Union{Symbol,Expr}},Nothing} = nothing
+
+function with_extra_state_variables(f, variables)
+    current_vars = copy(something(EXTRA_STATE_VARIABLES[], Union{Symbol,Expr}[]))
+    new_vars = append!(current_vars, variables)
+    with_context(f, EXTRA_STATE_VARIABLES => new_vars)
+end
 
 end