Extra context constructors (#374)

* Extra context constructors

* Simplify

* Update src/contexts.jl

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* add test

* fix

* formatting

* Update test/contexts.jl

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Update src/contexts.jl

Co-authored-by: David Widmann <[email protected]>

* Apply suggestions from review

* Update test/contexts.jl

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* More readable

* Remove inner constructor

* remove brackets

* Formatting

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Update src/contexts.jl

* Update src/contexts.jl

Co-authored-by: David Widmann <[email protected]>

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: David Widmann <[email protected]>

Author: 3 people

Project.toml

@@ -1,6 +1,6 @@
 name = "DynamicPPL"
 uuid = "366bfd00-2699-11ea-058f-f148b4cae6d8"
-version = "0.17.5"
+version = "0.17.6"
 
 [deps]
 AbstractMCMC = "80f14c24-f653-4e6a-9b94-39d6b0f70001"

src/contexts.jl

@@ -120,7 +120,11 @@ setleafcontext(::IsLeaf, ::IsLeaf, left, right) = right
 
 # Contexts
 """
-    SamplingContext(rng, sampler, context)
+    SamplingContext(
+            [rng::Random.AbstractRNG=Random.GLOBAL_RNG],
+            [sampler::AbstractSampler=SampleFromPrior()],
+            [context::AbstractContext=DefaultContext()],
+    )
 
 Create a context that allows you to sample parameters with the `sampler` when running the model.
 The `context` determines how the returned log density is computed when running the model.
@@ -132,10 +136,26 @@ struct SamplingContext{S<:AbstractSampler,C<:AbstractContext,R} <: AbstractConte
     sampler::S
     context::C
 end
-SamplingContext(sampler, context) = SamplingContext(Random.GLOBAL_RNG, sampler, context)
-SamplingContext(context::AbstractContext) = SamplingContext(SampleFromPrior(), context)
-SamplingContext(sampler::AbstractSampler) = SamplingContext(sampler, DefaultContext())
-SamplingContext() = SamplingContext(SampleFromPrior())
+
+function SamplingContext(
+    rng::Random.AbstractRNG=Random.GLOBAL_RNG, sampler::AbstractSampler=SampleFromPrior()
+)
+    return SamplingContext(rng, sampler, DefaultContext())
+end
+
+function SamplingContext(
+    sampler::AbstractSampler, context::AbstractContext=DefaultContext()
+)
+    return SamplingContext(Random.GLOBAL_RNG, sampler, context)
+end
+
+function SamplingContext(rng::Random.AbstractRNG, context::AbstractContext)
+    return SamplingContext(rng, SampleFromPrior(), context)
+end
+
+function SamplingContext(context::AbstractContext)
+    return SamplingContext(Random.GLOBAL_RNG, SampleFromPrior(), context)
+end
 
 NodeTrait(context::SamplingContext) = IsParent()
 childcontext(context::SamplingContext) = context.context

test/contexts.jl

@@ -256,4 +256,19 @@ end
         @test DynamicPPL.getsym(vn_prefixed) == Symbol("a.b.c.d.e.f.x")
         @test getlens(vn_prefixed) === getlens(vn)
     end
+
+    @testset "SamplingContext" begin
+        context = SamplingContext(Random.GLOBAL_RNG, SampleFromPrior(), DefaultContext())
+        @test context isa SamplingContext
+
+        # convenience constructors
+        @test SamplingContext() == context
+        @test SamplingContext(Random.GLOBAL_RNG) == context
+        @test SamplingContext(SampleFromPrior()) == context
+        @test SamplingContext(DefaultContext()) == context
+        @test SamplingContext(Random.GLOBAL_RNG, SampleFromPrior()) == context
+        @test SamplingContext(Random.GLOBAL_RNG, DefaultContext()) == context
+        @test SamplingContext(SampleFromPrior(), DefaultContext()) == context
+        @test SamplingContext(SampleFromPrior(), DefaultContext()) == context
+    end
 end