pi harness reimplement

src/stream_fn.jl

@@ -0,0 +1,45 @@
+"""
+    stream_fn.jl - Stream function utilities
+
+This module provides the default stream function configuration for AgentCore.
+"""
+
+module StreamFn
+
+using ..Types: StreamFn
+
+let default_stream_fn::Union{StreamFn, Nothing} = nothing
+
+"""
+    setDefaultStreamFn(stream_fn)
+
+Configure the fallback used by Agent and low-level loops when callers omit stream_fn.
+
+# Arguments
+- `stream_fn`: The stream function to set as default
+"""
+function setDefaultStreamFn(stream_fn::Union{StreamFn, Nothing})
+    global default_stream_fn = stream_fn
+end
+
+"""
+    getDefaultStreamFn()
+
+Get the configured default stream function, or throw an error if none is configured.
+
+# Returns
+- The configured stream function
+
+# Throws
+- ErrorException if no default stream function is configured
+"""
+function getDefaultStreamFn()::StreamFn
+    if isnothing(default_stream_fn)
+        throw(ErrorException(
+            "No default stream function configured. Pass stream_fn explicitly or call setDefaultStreamFn()."
+        ))
+    end
+    return default_stream_fn
+end
+
+end