ecdsa cross-tier validation blocked on `when` and `unless` being
unbound on the asm tier. R7RS standard control forms — present on
Python (lumbda.py) and C (c/) tiers, but absent on asm because the
existing macro facility (define-macro) only ships under CL_FULL.
Path B chosen (special-form dispatch table extension):
- sf_when / sf_unless length-prefixed symbol names
- sym_when_val / sym_unless_val interned at init_special_forms
- dispatch cases in .eval_top alongside .ev_and / .ev_or
- .ev_when / .ev_unless evaluators reuse .ev_begin for the body
branch and .ev_begin_void for the skip branch (TCO preserved)
Available on every asm tier (plain `lumbda`, `lumbda-gc`,
`lumbda-full`). Binary size impact:
lumbda 60488 → 60768 (+280, +0.46%)
lumbda-gc 69224 → 69496 (+272, +0.39%)
lumbda-full 71720 → 72000 (+280, +0.39%)
All 158 asm tests still pass. Tested truthy/falsy/multi-form bodies
on all three tiers. ecdsa search.lsp now runs on asm-full with output
byte-identical to Python tier (v3-clifford-only winner, score 0).
Note: ecdsa search.lsp also depends on `case`, which is only present
under CL_FULL (carved into cl_full_prelude as a define-macro form).
That gap blocks lumbda-gc cross-tier validation and is out of scope
for this commit.
russell@unturf.com
865be28091