add isSolvable fnc

Author: dehann

src/services/AbstractDFG.jl

@@ -327,6 +327,20 @@ function ls(dfg::G, label::Symbol)::Vector{Symbol} where G <: AbstractDFG
     return getNeighbors(dfg, label)
 end
 
+"""
+    $SIGNATURES
+
+Variables or factors may or may not be 'solvable', depending on a user definition.  Useful for ensuring atomic transactions.
+
+DevNotes:
+- Will be renamed to `var.solvable` -- see DFG #201
+
+Related
+
+isSolveInProgress
+"""
+isSolvable(var::Union{DFGVariable, DFGFactor}) = var.ready
+
 """
     $(SIGNATURES)
 Gets an empty and unique CloudGraphsDFG derived from an existing DFG.