forgot to add the experimenta.jl file in previous commit

src/experimental.jl

@@ -0,0 +1,64 @@
+module Experimental
+
+using DynamicPPL: DynamicPPL
+
+"""
+    is_suitable_varinfo(model::Model, context::AbstractContext, varinfo::AbstractVarInfo; kwargs...)
+
+Check if the `model` supports evaluation using the provided `context` and `varinfo`.
+
+!!! warning
+    Loading JET.jl is required before calling this function.
+
+# Arguments
+- `model`: The model to to verify the support for.
+- `context`: The context to use for the model evaluation.
+- `varinfo`: The varinfo to verify the support for.
+
+# Keyword Arguments
+- `only_ddpl`: If `true`, only consider error reports occuring in the tilde pipeline. Default: `true`.
+
+# Returns
+- `issuccess`: `true` if the model supports the varinfo, otherwise `false`.
+- `report`: The result of `report_call` from JET.jl.
+"""
+function is_suitable_varinfo end
+
+# Internal hook for JET.jl to overload.
+function _determine_varinfo_jet end
+
+"""
+    determine_suitable_varinfo(model[, context]; verbose::Bool=false, only_ddpl::Bool=true)
+
+Return a suitable varinfo for the given `model`.
+
+See also: [`DynamicPPL.is_suitable_varinfo`](@ref).
+
+!!! warning
+    For full functionality, this requires JET.jl to be loaded.
+    If JET.jl is not loaded, this function will assume the model is compatible with typed varinfo.
+
+# Arguments
+- `model`: The model for which to determine the varinfo.
+- `context`: The context to use for the model evaluation. Default: `SamplingContext()`.
+
+# Keyword Arguments
+- `only_ddpl`: If `true`, only consider error reports within DynamicPPL.jl.
+"""
+function determine_suitable_varinfo(
+    model::DynamicPPL.Model,
+    context::DynamicPPL.AbstractContext=DynamicPPL.SamplingContext();
+    only_ddpl::Bool=true,
+)
+    # If JET.jl has been loaded, and thus `determine_varinfo` has been defined, we use that.
+    return if Base.get_extension(DynamicPPL, :DynamicPPLJETExt) !== nothing
+        _determine_varinfo_jet(model, context; only_ddpl)
+    else
+        # Warn the user.
+        @warn "JET.jl is not loaded. Assumes the model is compatible with typed varinfo."
+        # Otherwise, we use the, possibly incorrect, default typed varinfo (to stay backwards compat).
+        DynamicPPL.typed_varinfo(model, context)
+    end
+end
+
+end