Execution backends

Compiler targets beneath the organs, never beside them. A backend holds no truth, identity, authority or money and cannot perform an effect; it is chosen on measured cost. Declared availability is a claim about the estate, and presence on a given machine is a separate fact.

backend
reference
kind
interpreter
availability
available
version
python3
cost_metric
wall_seconds
measured
backend
hvm2
kind
interaction_net
availability
available
version
2.0.22
cost_metric
interactions
measured
lowered the retained-and-observed frontier over 30 live twins: 26 survivors, identical to the reference backend, at 320 interactions. A function that does not inspect its argument costs 3 interactions over a k-way superposition for every k measured to 32, against 2k+1 for k separate applications.
backend
hvm4
kind
interaction_net
availability
available
version
4.0 (pre-launch, per its own README)
cost_metric
interactions
measured
same 30-twin frontier as hvm2 and the reference: 26 survivors, identical set, 188 interactions against hvm2 320 on this encoding. Its own banner calls it a sequential runtime, so this is a different calculus rather than a more parallel HVM2.
backend
bend
kind
language_frontend
availability
available
version
bend-lang 0.2.38
cost_metric
interactions
measured
compiles the candidate predicate and folds it over a tree, returning an aggregate rather than the frontier