Add provide/context/emit!/emitted — render-time dynamic scope

Four new primitives for scoped downward value passing and upward
accumulation through the render tree. Specced in .sx, bootstrapped
to Python and JS across all adapters (eval, html, sx, dom, async).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-03-13 02:58:21 +00:00
parent 41097eeef9
commit ea2b71cfa3
14 changed files with 436 additions and 18 deletions

View File

@@ -60,6 +60,46 @@ def _collect_reset():
_collect_buckets = {}
# Render-time dynamic scope stacks (provide/context/emit!)
_provide_stacks: dict[str, list[dict]] = {}
def provide_push(name, value=None):
"""Push a provider scope with name, value, and empty emitted list."""
_provide_stacks.setdefault(name, []).append({"value": value, "emitted": []})
def provide_pop(name):
"""Pop the most recent provider scope for name."""
if name in _provide_stacks and _provide_stacks[name]:
_provide_stacks[name].pop()
def sx_context(name, *default):
"""Read value from nearest enclosing provider. Error if no provider and no default."""
if name in _provide_stacks and _provide_stacks[name]:
return _provide_stacks[name][-1]["value"]
if default:
return default[0]
raise RuntimeError(f"No provider for: {name}")
def sx_emit(name, value):
"""Append value to nearest enclosing provider's accumulator. Error if no provider."""
if name in _provide_stacks and _provide_stacks[name]:
_provide_stacks[name][-1]["emitted"].append(value)
else:
raise RuntimeError(f"No provider for emit!: {name}")
return NIL
def sx_emitted(name):
"""Return list of values emitted into nearest matching provider."""
if name in _provide_stacks and _provide_stacks[name]:
return list(_provide_stacks[name][-1]["emitted"])
return []
def sx_truthy(x):
"""SX truthiness: everything is truthy except False, None, and NIL."""
if x is False:
@@ -905,6 +945,12 @@ PRIMITIVES["spread-attrs"] = spread_attrs
PRIMITIVES["collect!"] = sx_collect
PRIMITIVES["collected"] = sx_collected
PRIMITIVES["clear-collected!"] = sx_clear_collected
# provide/context/emit! — render-time dynamic scope
PRIMITIVES["provide-push!"] = provide_push
PRIMITIVES["provide-pop!"] = provide_pop
PRIMITIVES["context"] = sx_context
PRIMITIVES["emit!"] = sx_emit
PRIMITIVES["emitted"] = sx_emitted
def is_primitive(name):
@@ -1349,6 +1395,8 @@ def eval_list(expr, env):
return sf_shift(args, env)
elif sx_truthy((name == 'dynamic-wind')):
return sf_dynamic_wind(args, env)
elif sx_truthy((name == 'provide')):
return sf_provide(args, env)
elif sx_truthy((name == 'map')):
return ho_map(args, env)
elif sx_truthy((name == 'map-indexed')):
@@ -1840,6 +1888,19 @@ def sf_dynamic_wind(args, env):
call_thunk(after, env)
return result
# sf-provide
def sf_provide(args, env):
_cells = {}
name = trampoline(eval_expr(first(args), env))
val = trampoline(eval_expr(nth(args, 1), env))
body_exprs = slice(args, 2)
_cells['result'] = NIL
provide_push(name, val)
for e in body_exprs:
_cells['result'] = trampoline(eval_expr(e, env))
provide_pop(name)
return _cells['result']
# expand-macro
def expand_macro(mac, raw_args, env):
local = env_merge(macro_closure(mac), env)
@@ -2189,7 +2250,7 @@ def render_value_to_html(val, env):
return escape_html(sx_str(val))
# RENDER_HTML_FORMS
RENDER_HTML_FORMS = ['if', 'when', 'cond', 'case', 'let', 'let*', 'begin', 'do', 'define', 'defcomp', 'defisland', 'defmacro', 'defstyle', 'defhandler', 'deftype', 'defeffect', 'map', 'map-indexed', 'filter', 'for-each']
RENDER_HTML_FORMS = ['if', 'when', 'cond', 'case', 'let', 'let*', 'begin', 'do', 'define', 'defcomp', 'defisland', 'defmacro', 'defstyle', 'defhandler', 'deftype', 'defeffect', 'map', 'map-indexed', 'filter', 'for-each', 'provide']
# render-html-form?
def is_render_html_form(name):
@@ -2291,6 +2352,15 @@ def dispatch_html_form(name, expr, env):
f = trampoline(eval_expr(nth(expr, 1), env))
coll = trampoline(eval_expr(nth(expr, 2), env))
return join('', filter(lambda r: (not sx_truthy(is_spread(r))), map(lambda item: (render_lambda_html(f, [item], env) if sx_truthy(is_lambda(f)) else render_to_html(apply(f, [item]), env)), coll)))
elif sx_truthy((name == 'provide')):
prov_name = trampoline(eval_expr(nth(expr, 1), env))
prov_val = trampoline(eval_expr(nth(expr, 2), env))
body_start = 3
body_count = (len(expr) - 3)
provide_push(prov_name, prov_val)
result = (render_to_html(nth(expr, body_start), env) if sx_truthy((body_count == 1)) else join('', filter(lambda r: (not sx_truthy(is_spread(r))), map(lambda i: render_to_html(nth(expr, i), env), range(body_start, (body_start + body_count))))))
provide_pop(prov_name)
return result
else:
return render_value_to_html(trampoline(eval_expr(expr, env)), env)
@@ -2529,7 +2599,7 @@ def aser_call(name, args, env):
return sx_str('(', join(' ', parts), ')')
# SPECIAL_FORM_NAMES
SPECIAL_FORM_NAMES = ['if', 'when', 'cond', 'case', 'and', 'or', 'let', 'let*', 'lambda', 'fn', 'define', 'defcomp', 'defmacro', 'defstyle', 'defhandler', 'defpage', 'defquery', 'defaction', 'defrelation', 'begin', 'do', 'quote', 'quasiquote', '->', 'set!', 'letrec', 'dynamic-wind', 'defisland', 'deftype', 'defeffect']
SPECIAL_FORM_NAMES = ['if', 'when', 'cond', 'case', 'and', 'or', 'let', 'let*', 'lambda', 'fn', 'define', 'defcomp', 'defmacro', 'defstyle', 'defhandler', 'defpage', 'defquery', 'defaction', 'defrelation', 'begin', 'do', 'quote', 'quasiquote', '->', 'set!', 'letrec', 'dynamic-wind', 'defisland', 'deftype', 'defeffect', 'provide']
# HO_FORM_NAMES
HO_FORM_NAMES = ['map', 'map-indexed', 'filter', 'reduce', 'some', 'every?', 'for-each']
@@ -2626,6 +2696,15 @@ def aser_special(name, expr, env):
elif sx_truthy(((name == 'define') if sx_truthy((name == 'define')) else ((name == 'defcomp') if sx_truthy((name == 'defcomp')) else ((name == 'defmacro') if sx_truthy((name == 'defmacro')) else ((name == 'defstyle') if sx_truthy((name == 'defstyle')) else ((name == 'defhandler') if sx_truthy((name == 'defhandler')) else ((name == 'defpage') if sx_truthy((name == 'defpage')) else ((name == 'defquery') if sx_truthy((name == 'defquery')) else ((name == 'defaction') if sx_truthy((name == 'defaction')) else ((name == 'defrelation') if sx_truthy((name == 'defrelation')) else ((name == 'deftype') if sx_truthy((name == 'deftype')) else (name == 'defeffect')))))))))))):
trampoline(eval_expr(expr, env))
return NIL
elif sx_truthy((name == 'provide')):
prov_name = trampoline(eval_expr(first(args), env))
prov_val = trampoline(eval_expr(nth(args, 1), env))
_cells['result'] = NIL
provide_push(prov_name, prov_val)
for body in slice(args, 2):
_cells['result'] = aser(body, env)
provide_pop(prov_name)
return _cells['result']
else:
return trampoline(eval_expr(expr, env))
@@ -3759,7 +3838,7 @@ async def async_map_render(exprs, env, ctx):
return results
# ASYNC_RENDER_FORMS
ASYNC_RENDER_FORMS = ['if', 'when', 'cond', 'case', 'let', 'let*', 'begin', 'do', 'define', 'defcomp', 'defisland', 'defmacro', 'defstyle', 'defhandler', 'deftype', 'defeffect', 'map', 'map-indexed', 'filter', 'for-each']
ASYNC_RENDER_FORMS = ['if', 'when', 'cond', 'case', 'let', 'let*', 'begin', 'do', 'define', 'defcomp', 'defisland', 'defmacro', 'defstyle', 'defhandler', 'deftype', 'defeffect', 'map', 'map-indexed', 'filter', 'for-each', 'provide']
# async-render-form?
def async_render_form_p(name):
@@ -3823,6 +3902,15 @@ async def dispatch_async_render_form(name, expr, env, ctx):
f = (await async_eval(nth(expr, 1), env, ctx))
coll = (await async_eval(nth(expr, 2), env, ctx))
return join('', filter(lambda r: (not sx_truthy(is_spread(r))), (await async_map_fn_render(f, coll, env, ctx))))
elif sx_truthy((name == 'provide')):
prov_name = (await async_eval(nth(expr, 1), env, ctx))
prov_val = (await async_eval(nth(expr, 2), env, ctx))
body_start = 3
body_count = (len(expr) - 3)
provide_push(prov_name, prov_val)
result = ((await async_render(nth(expr, body_start), env, ctx)) if sx_truthy((body_count == 1)) else (lambda results: join('', filter(lambda r: (not sx_truthy(is_spread(r))), results)))((await async_map_render(slice(expr, body_start), env, ctx))))
provide_pop(prov_name)
return result
else:
return (await async_render((await async_eval(expr, env, ctx)), env, ctx))
@@ -4148,7 +4236,7 @@ async def async_aser_call(name, args, env, ctx):
return make_sx_expr(sx_str('(', join(' ', parts), ')'))
# ASYNC_ASER_FORM_NAMES
ASYNC_ASER_FORM_NAMES = ['if', 'when', 'cond', 'case', 'and', 'or', 'let', 'let*', 'lambda', 'fn', 'define', 'defcomp', 'defmacro', 'defstyle', 'defhandler', 'defpage', 'defquery', 'defaction', 'begin', 'do', 'quote', '->', 'set!', 'defisland', 'deftype', 'defeffect']
ASYNC_ASER_FORM_NAMES = ['if', 'when', 'cond', 'case', 'and', 'or', 'let', 'let*', 'lambda', 'fn', 'define', 'defcomp', 'defmacro', 'defstyle', 'defhandler', 'defpage', 'defquery', 'defaction', 'begin', 'do', 'quote', '->', 'set!', 'defisland', 'deftype', 'defeffect', 'provide']
# ASYNC_ASER_HO_NAMES
ASYNC_ASER_HO_NAMES = ['map', 'map-indexed', 'filter', 'for-each']
@@ -4242,6 +4330,15 @@ async def dispatch_async_aser_form(name, expr, env, ctx):
elif sx_truthy(((name == 'define') if sx_truthy((name == 'define')) else ((name == 'defcomp') if sx_truthy((name == 'defcomp')) else ((name == 'defmacro') if sx_truthy((name == 'defmacro')) else ((name == 'defstyle') if sx_truthy((name == 'defstyle')) else ((name == 'defhandler') if sx_truthy((name == 'defhandler')) else ((name == 'defpage') if sx_truthy((name == 'defpage')) else ((name == 'defquery') if sx_truthy((name == 'defquery')) else ((name == 'defaction') if sx_truthy((name == 'defaction')) else ((name == 'deftype') if sx_truthy((name == 'deftype')) else (name == 'defeffect'))))))))))):
(await async_eval(expr, env, ctx))
return NIL
elif sx_truthy((name == 'provide')):
prov_name = (await async_eval(first(args), env, ctx))
prov_val = (await async_eval(nth(args, 1), env, ctx))
_cells['result'] = NIL
provide_push(prov_name, prov_val)
for body in slice(args, 2):
_cells['result'] = (await async_aser(body, env, ctx))
provide_pop(prov_name)
return _cells['result']
else:
return (await async_eval(expr, env, ctx))