Phase 5 cont. Adds `select` statement evaluation:
go-select-try-case env COMM →
:not-ready / extended-env / :eval-error
go-select-pick env CASES DEFAULT-OR-NIL →
body-result / blocked-error
go-eval-select-stmt env STMT — public entry
Walks cases in declared order:
* :send case — always ready in v0 (unbounded buffer). Sends value
via go-chan-send! and returns env unchanged.
* :short-decl / :assign case — RHS expected to be unary <- on a
channel. Ready iff go-chan-len > 0; on success, recv-into-var
binds the new value in env.
* Bare recv (:app (:var "<-") [CHAN]) — ready iff len > 0; consumes
the value (discarded).
* :default — deferred until end of walk. Runs if no other case
ready. Absence + no ready case → (:eval-error :select-blocked-
no-default).
New `go-chan-len` accessor on the channel closure-bundle so the
select can peek without consuming.
Subtle bug fix: the :select stmt branch in go-eval-stmt was returning
the old env instead of the env returned by the case body. Assignments
inside select cases (`select { case <-ch: x = 1 ; default: x = 99 }`)
now stick.
Tests (6):
default fires when no case ready
recv case fires when ready
recv-into-var binds the value
send case always ready
picks first ready case (deterministic order in v0)
no default + nothing ready → blocked error
combined with goroutine fan-in
runtime 18/18, total 475/475.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 5 (goroutines + channels) opens.
lib/go/sched.sx is the **independent implementation** referenced by
plans/lib-guest-scheduler.md — the first-consumer cut whose realised
shape will inform the eventual sister kit.
Channel representation:
(list :go-chan SEND-FN RECV-FN CLOSED?-FN CLOSE!-FN)
Each closure shares a mutable `buf` (a list mutated via append! and
set!) and a `closed` flag. Channel identity is closure-instance —
two `make()` calls produce distinct values per Go spec § Channel types.
Primitive API in sched.sx:
go-make-chan / go-chan? / go-chan-send! / go-chan-recv! /
go-chan-closed? / go-chan-close!
Eval integration in eval.sx:
* `make` and `close` added as builtins. v0 `make()` takes no args
and returns an unbounded-buffer channel.
* `:send` stmt → go-chan-send! on the channel.
* Unary `<-` recv on channel values → go-chan-recv!. `:empty`
sentinel converted to nil (stand-in for blocking semantics).
* `:go expr` → synchronous eval (v0 limitation, see sched.sx
header).
**v0 concurrency model — synchronous goroutines.** SX doesn't expose
first-class continuations to guest code, so v0 runs `go f()`
immediately and depends on the spawned goroutine running to
completion before the main goroutine receives. This is the right
semantics for the simple producer/consumer patterns covered here.
True preemption with blocking send/recv is Phase 5b — requires either
a CEK-style trampolining eval rewrite or kit-level continuation
support. Logged in sched.sx header and in the sister-plan diary.
Runtime suite (12 tests):
* 6 direct API tests: identity, FIFO order, closed-flag
* 6 source-level: make + send + recv, go ping-pong, close,
multi-goroutine fan-in, worker-with-result
Sister-plan scheduler diary updated with the channel-as-closure-
bundle insight and the v0 synchronous-spawn caveat.
runtime 12/12, total 469/469.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 4 cont. The crossings:
* Method dispatch — Methods record under #method/TYPE/NAME (same
mangled-key scheme the type checker uses, intentionally so eval
and type checker can converge on a shared method-table protocol
later). go-eval-method-call: lookup the receiver type's method,
bind receiver param to the struct value, evaluate body. Value and
pointer receivers treated the same in v0 (pointer semantics not
modelled yet).
* Method-call dispatch — In go-eval's :app branch, head=:select
routes to go-eval-method-call. If the receiver is not a struct,
falls back to the field-as-callable path.
* Unary prefix ops — go-eval's :app branch checks for 1-arg :var
head with op name "-" / "+" / "!". (Other unary ops like
*p / &v / <-ch / ^x deferred until pointer / channel / bitwise
semantics arrive.)
End-to-end programs verified:
* recursive fib(10) = 55
* struct + method + iterative loop (counter bump 7 times)
* linear search (returns index or -1)
* factorial via method on Counter (= 120)
* count odd numbers in 1..10 = 5
**Phase 4 acceptance bar (80+) crossed: eval 80/80, total 457/457.**
Remaining Phase 4 work (closures, multi-return, full slice triple,
pointer semantics) refines but doesn't gate Phase 5 (goroutines).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 4 cont. Adds runtime support for Go's struct type.
Struct representation: (list :go-struct TYPE-NAME FIELDS) where
FIELDS is an association list of (field-name value) pairs.
`type T struct { ... }` is now significant at eval-time. The new
go-eval-type-decl registers field-name lists in env under
(:go-struct-type FIELD-NAMES) so positional composite literals can
map argument positions to field names. Non-struct type aliases are
silent no-ops in v0.
go-eval-composite extended:
* If type is (:var TYPE-NAME), look up in env. Must be a
:go-struct-type entry — error otherwise.
* go-eval-struct-lit branches on whether the first elem is :kv
(keyed) or not (positional). Keyed mode reads key-name from each
:kv's key (which is a :var node). Positional mode arity-checks
against the field-names list and zips positionally.
go-eval-select handles (:select OBJ FIELD-NAME) — field lookup with
go-map-get on the FIELDS assoc list.
go-eval-assign-pairs gets a new (:select OBJ FIELD) LHS branch:
- var-rooted only for v0
- rebuilds the struct via go-map-set, rebinds the var
**Functions taking and returning structs round-trip end-to-end:**
type Point struct { x, y int }
func add(a, b Point) Point { return Point{a.x + b.x, a.y + b.y} }
add(Point{1, 2}, Point{3, 4}) // Point{4, 6}
Method-dispatch (calling p.M() where M is a method on Point's type)
is the next step; needs threading the type checker's #method/T/N
scheme into eval-time so functions can be looked up by receiver type.
eval 66/66, total 443/443.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 4 cont. Adds map values and index-assignment for both
slices and maps.
Map representation: (list :go-map ENTRIES) where ENTRIES is an
association list of (key value) pairs.
go-map-get / go-map-set — primitive lookup + functional-update.
go-slice-set — same idea for slices.
go-extract-map-entries reads each :kv element in a composite literal,
evaluating key and value. go-eval-composite dispatches on :ty-map to
build the :go-map value.
go-eval-index extended: when OBJ is a :go-map, look up the key via
go-map-get. Missing keys return nil in v0 (Go's real semantics is
the zero value of the value type — needs runtime type info that this
slice doesn't yet thread through).
go-eval-builtin's len handles :go-map alongside :go-slice and strings.
go-eval-assign-pairs gets a new branch for (:index OBJ IDX) LHS:
- var-rooted indexing only (a[i] = v / m["k"] = v)
- slice → go-slice-set then rebind the var
- map → go-map-set then rebind the var
**Word-counter via map[string]int works end-to-end:**
words := []string{"a", "b", "a", "c", "a"}
counts := map[string]int{}
for i := 0; i < len(words); i++ {
counts[words[i]] = counts[words[i]] + 1
}
// counts["a"] == 3
Builds on:
- map composite literal eval
- map index lookup
- map index-assign
- slice indexing
- len() builtin
- nil + 1 = 1 (numeric-coercion of missing-key default)
eval 58/58, total 435/435.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 4 cont. Adds runtime support for Go's slice type.
Slice representation: (list :go-slice ELEMS) — a simple wrapper around
a list of element values. v0 deferring the full
(length, capacity, backing-vector) triple from the Go spec until
programs need it.
go-eval-composite → for (:composite TYPE-OR-EXPR ELEMS) where
TYPE is :ty-slice / :ty-array, eval each
element (handling :kv index-keyed
shorthand by taking only the value) and
wrap in :go-slice.
go-eval-index → (:index OBJ IDX). Bounds-checked; out-of-
range returns (:eval-error :index-out-of-range).
go-eval-slice → (:slice OBJ LOW HIGH MAX). Two-index slice
with omitted low → 0, omitted high → len.
Returns a new :go-slice.
go-list-slice → primitive list-slicing helper.
Builtins live in a new starter env go-env-builtins:
len(slice|string) → count
append(slice, ...x) → new slice with x appended
print(...) → no-op in v0
Builtins are bound as (:go-builtin NAME); go-eval-call recognises the
shape and routes to go-eval-builtin instead of go-eval-fn.
**Summing a slice via the canonical Go for-loop works end-to-end:**
a := []int{1, 2, 3, 4, 5}
sum := 0
for i := 0; i < len(a); i++ {
sum = sum + a[i]
}
// sum == 15
eval 50/50, total 427/427.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 4 cont. go-eval-for handles all three for-header shapes:
for { ... } — infinite (cond defaults to true)
for cond { ... } — while-like (init=nil, post=nil)
for init ; cond ; post { ... } — C-style
Implementation:
* Run INIT (if any), extending env.
* Loop: eval COND. If false, exit with current env.
Eval body (a :block). Catch sentinels:
:return-value → propagate up
:break → exit loop with pre-break env
:continue → still runs POST, then re-loops
Otherwise: run POST, re-loop.
:break and :continue propagate as keyword sentinels through
go-eval-block alongside the existing :return-value sentinel. The
block returns whichever sentinel hit first; control-flow constructs
(for, switch, select) catch them.
inc-dec (x++ / x--) updates env via the same shadowing model used by
assign — `(go-env-extend env name (+ current 1))`.
**Iterative fact(5) = 120 and the classic sum-to-9 = 45 both
evaluate.** Demonstrates the for-loop machinery is solid enough for
real programs.
eval 40/40, total 417/417.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 4 cont. go-eval-stmt dispatches on:
:return → wraps value in (:return-value V) sentinel
:var-decl → bind each NAME via go-eval-var-decl
:short-decl → bind each (:var NAME) lhs to corresponding expr value
:assign → immutable-env shadowing (true mutation deferred)
:block → run stmts via go-eval-block, propagating :return-value
:if / :else → cond-driven dispatch
:func-decl → bind name to (list :go-fn PARAMS BODY)
else → expression statement, evaluate for side effects
go-eval-call extends the CALLER's env with param-names → arg-values
(dynamic-scope-ish — closures don't capture lexical env yet), runs the
body block, catches :return-value and unwraps.
**Recursive fib(5) = 5 evaluates correctly.** Recursion works because
top-level func bindings are in the calling env before the recursive
call happens.
True lexical closures (let bind sees outer var; assignments visible to
nested funcs) need an env-cell model with mutation; deferred to a
later slice.
eval 33/33, total 410/410.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 3 — bidirectional type checker — is fully ticked (short-decl
was already implemented). Phase 4 starts here.
lib/go/eval.sx single judgment:
(go-eval ENV EXPR) → VALUE | (list :eval-error TAG ...)
ENV is an association list of (NAME VALUE) bindings — same shape as
the type checker's ctx, but the entries are runtime values. Values
are represented directly in SX: integers/floats as SX numbers,
strings as SX strings, booleans as true/false, nil as nil. Composite
values (slices/maps/structs/pointers/channels) arrive in later slices.
First-slice coverage:
* go-env-empty / -lookup / -extend
* Literal decoding:
decimal (with underscores)
hex (0x.. / 0X..)
oct (0o.. / 0O..)
bin (0b.. / 0B..)
via go-hex-digit-value (explicit char equality — SX's nth on
strings returns single-char strings, not numeric codes; the
arithmetic-on-char-codes pattern from the OCaml kernel ports
doesn't work here).
* Identifier lookup with predeclared true / false / nil.
* Binops: + - * / and the six comparison ops and && / ||.
* Errors as (:eval-error TAG ...) sentinels.
Statements (block / return / short-decl / assign), control flow
(if / for), and function application / closures arrive in subsequent
slices.
eval 25/25, total 402/402.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 3 cont. The headline Go-distinguishing typing feature: interfaces
are satisfied *structurally and silently* — no `implements` declaration,
no nominal subtyping. Any type whose method set contains all the
interface's methods (with matching signatures) satisfies it.
Method declarations now type-check via go-check-method-decl:
* Receiver type extracted (T or *T → "T") via go-extract-recv-ty-name.
* Method signature (:ty-func PARAMS RESULTS) bound under a mangled
key "#method/RECV-NAME/METHOD-NAME" in ctx.
* Body checked with receiver + params extended into the body ctx.
go-iface-satisfies? CTX TY-NAME IFACE-TYPE walks the interface's
:method elements; for each, looks up #method/TY-NAME/METHOD-NAME and
compares (PARAMS, RESULTS) tuples. Embedded interfaces (:embed
elements) skipped in v0 — recursive interface resolution later.
Tests:
* method-decl binds under #method/Point/String
* pointer-receiver method also keys the base type
* Point with String() satisfies interface { String() string }
* empty type does NOT satisfy Stringer
* arity-mismatch method fails satisfaction
* multi-method satisfaction works
* partial method-set fails
types 72/72, total 377/377. Phase 3 sub-deliverable list is now
substantially complete; only AST-path error context remains as a UX
sharpener.
Sister-plan static-types-bidirectional diary updated with the
**constraint-satisfies? pluggable predicate** kit-API proposal —
third pluggable point after synth/check + assignable?. Go interfaces,
Haskell typeclasses, Rust traits, and TS structural subtyping all
answer "does this value-type fit this constraint-type?" with
different machinery; the kit's check uses constraint-satisfies? when
EXPECTED is itself a constraint type.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 3 cont. Adds composite-literal type-checking via go-synth-composite:
[]T{...} — go-check-composite-elems with VAL-TY=T, KEY-TY=nil.
Each plain elem assignable to T; :kv element accepted
(Go's index-keyed shorthand: `[]int{0: 5, 1: 10}`)
with only the value checked.
[N]T{...} — same as slice; result :ty-array N T.
map[K]V{...} — KEY-TY=K, VAL-TY=V. Each :kv pair: key assignable
to K, value to V. Non-:kv elements in maps are
(:type-error :map-elem-missing-key).
The literal's *synthesised* type is the type expression itself, so
nested composites fall out by recursion:
[][]int{[]int{1,2}, []int{3,4}}
→ outer: go-check-composite-elems with VAL-TY=[]int
→ each inner []int{1,2} goes through go-synth-composite recursively,
yielding :ty-slice :ty-name "int" — assignable-equal to VAL-TY.
Coverage: positive cases (homogeneous slices/arrays/maps, empty
slice, nested), and three negative cases (slice element mismatch,
map key mismatch, map value mismatch). Also a decl test:
var x = []int{1, 2, 3} → binds x to :ty-slice :ty-name "int"
Named-type literals (`Point{1,2}`, `pkg.T{...}`) need type-decl-driven
field resolution; deferred. Interface satisfaction and AST-path error
context also remain — neither gates Phase 4.
**Phase 3 acceptance bar (60+) crossed: types 65/65, total 370/370.**
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 3 cont. The expression-synth :app dispatch is now bifurcated:
* go-is-binop-call? — head is :var with an operator name AND 2 args
AND the operator is in one of the binop tables. Short-circuits to
go-synth-binop as before.
* Everything else routes to go-synth-call.
go-synth-call:
1. Synth the callee. Must produce a (list :ty-func PARAMS RESULTS).
Otherwise → (:type-error :not-callable TYPE).
2. Arity-check args vs params. Mismatch → (:type-error :arity-mismatch).
3. go-check-args-against: each arg assignable to corresponding param
(untyped-constant flow works — `f(42)` accepts the untyped int
into an int param).
4. Result by count:
0 results → (list :ty-void)
1 result → that result directly
N results → (list :ty-tuple TYPES) for multi-return
The recursive case lights up: go-check-func-decl binds the function
in its own body's ctx before checking. So:
func fib(n int) int { return fib(n) + fib(n) }
now type-checks because `fib` resolves inside the body, synth-call
sees its `:ty-func` and verifies the recursive call. Multi-return
functions destructure into `:ty-tuple` which short-decl will need to
consume next iteration.
types 55/55, total 360/360.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 3 cont. Adds:
* go-check-func-decl — binds the function in the outer ctx (recursive
self-reference will work once call-checking lands), extends the
body's ctx with each :field param group via go-ctx-extend-field
(the binding-group shape's *third* consumer in the type checker;
five total across parser+typer when counted with struct fields,
var-decls, const-decls, func params, method receivers).
* go-check-stmt — dispatches on :return / :assign / :var-decl /
:const-decl / :short-decl / :type-decl / :block; falls back to
go-synth for expression statements.
* go-check-block — threads ctx through stmts so that decls inside
the block extend the ctx for subsequent stmts.
* go-check-return-list — each return expr assignable to the
corresponding declared result type; mismatch counts are typed.
* go-check-assign / go-check-assign-pairs — RHS assignable to LHS
synthesised type, count mismatch typed.
* Helpers: go-decl-params-to-ty-list (flattens :field NAMES TYPE to
a flat list of N types), go-extend-with-params (folds extend-field
over a param-group list), go-repeat-ty.
Coverage tests:
func empty() {} → ok
func add(x, y int) int { return x + y } → ok
func bad() int { return "hi" } → typed error
func sig(x int) int → signature-only binds
func sumsq(x, y int) int { return x*x + y*y } → params visible
func two() int { var x int = 1; var y int = 2; → nested decl
return x + y }
func g() int { var x int; x = 5; return x } → assign verified
types 47/47, total 352/352.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 3 cont. Adds go-check-decl which dispatches on AST shape and
returns either the extended context or a :type-error:
:var-decl (:field NAMES TYPE-or-nil) EXPRS-or-nil
:const-decl (same shape; same logic in v0 — mutability later)
:short-decl LHS-LIST EXPRS (lhs is a list of :var nodes)
:type-decl NAME TYPE (type alias)
New helpers:
go-default-type — untyped-int → int, untyped-float → float64,
etc. Used when inferring var x = EXPR.
go-check-exprs-against — every expr assignable to the declared type.
go-bind-names-to-synth — pair names with default-typed synth of
corresponding exprs; extends ctx.
The canonical Go pitfall flows through end-to-end now:
(go-check-decl ctx (go-parse "var x float64 = 42 / 7"))
→ ctx + (x → float64)
Because: 42/7 synthesises to ty-untyped-int (binop result of two
untyped operands), then go-check-exprs-against uses go-type-assignable?
to check ty-untyped-int → ty-name "float64" — :ok via the
untyped-int-to-any-numeric assignability rule. The 6 (integer) result
gets float-converted on assignment, never floated mid-computation.
types 40/40, total 345/345.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Phase 3 cont. Adds:
* go-classify-literal-string — heuristic detection of literal kind
from the value-string (parser strips lexer's kind tag; flagged for
follow-up to extend AST shape).
* go-synth-literal — :ty-untyped-int / -float / -imag / -string.
* go-synth-binop — arithmetic, bitwise, comparison, logical ops with
untyped-constant unification:
untyped-int + untyped-float → untyped-float
untyped + typed → typed
comparison ops → bool
logical ops → bool
* go-untyped? + go-type-assignable? — pluggable assignability that
swaps in where structural equality used to gate go-check. Untyped
int assignable to any numeric type; untyped float assignable to
float/complex; untyped string to string.
**Canonical Go pitfall handled correctly**: `var x float64 = 42 / 7`
parses to a binop, synth produces :ty-untyped-int (since BOTH operands
are untyped, the int division stays in the int domain), and check
against float64 returns :ok via assignability. Wrong implementations
that float-coerce eagerly would give 6.0; the right behaviour is
"compute 6 as int, then convert to float64 = 6.0".
Verified by test "binop: 42 / 7 assignable to float64 (canonical
pitfall)" and the type-only test "binop: 42 / 7 — untyped int".
Sister-plan static-types-bidirectional diary updated with the
**pluggable-assignable-predicate** kit-API proposal:
(check-with assignable? CTX EXPR EXPECTED)
Each consumer plugs in its own variance discipline (Go untyped-flow,
TS structural subtyping, Rust lifetime-aware identity) without
rewriting synth or the judgment skeleton.
types 28/28, total 333/333.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
First slice of Phase 3 (bidirectional type checker).
lib/go/types.sx defines:
* go-ctx-empty / go-ctx-extend / go-ctx-lookup — context as a value.
* go-ctx-extend-field — consumes the (:field NAMES TYPE) shape from
the parser, binding every name to the shared type. This is the
cross-deliverable validation of the :field binding-group
observation made during Phase 2 func decls: parser produces it,
type checker consumes it, same shape end-to-end.
* go-predeclared — true / false / nil baked in. Full list expanded
on demand.
* go-synth — currently handles variable lookup; literals / calls /
binops follow in subsequent iterations.
* go-check — v0 defers to synth + structural type equality. Untyped-
constant flow and assignment-compatibility relations land later.
* Type errors carry first-class tags (:unbound, :mismatch,
:unsupported-synth) so consumers and tooling can dispatch.
Conformance.sh wired with new types suite. Scoreboard cleanup: drop
the "pending" types row since the suite is now real.
types 12/12, total 317/317. Phase 3 underway.
Sister-plan static-types-bidirectional diary updated with the
synth/check shape: judgment skeleton, error tag structure, and the
proposal that `check` should accept a `subtype?` predicate parameter
so each consumer (Go untyped-constants, TS variance, Rust lifetimes)
plugs in its own variance discipline without rewriting the judgment.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Final Phase 2 sub-deliverable. go-parse now handles whole Go files:
- Empty source → nil
- Single top-level form → that form (backward-compatible with ~169
existing single-stmt / single-decl tests)
- Multiple forms → (list :file FORMS), the canonical Go file shape
Implementation: gp-parse-all loops gp-parse-top until eof, tolerating
ASI semis between forms, then returns based on form count.
End-to-end test set (asserts the top-level decl-tag sequence via a
new decl-tags helper, not the full AST tree — that'd be unwieldy):
- hello-world :package :import :func-decl
- recursive fibonacci :package :func-decl
- FizzBuzz :package :import :func-decl
- goroutine ping-pong :package :func-decl :func-decl
- struct + method :package :type-decl :method-decl :func-decl
- interface + method :package :type-decl :type-decl :method-decl
- defer + select + range :package :func-decl
Type-switch (`switch v := x.(type) { ... }`) is the one syntactic
shape still deferred from Phase 2; doesn't gate Phase 3.
**Phase 2 (parser) is complete.** parse 176/176, total 305/305. Next:
Phase 3 — bidirectional type checker. The sister-plan diary for
static-types-bidirectional already has the :field binding-group
insight; Phase 3 will add the synth/check shape that emerges.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go's switch and select statements:
switch TAG { case V1, V2: a; case V3: b; default: c }
switch { case cond: ... } — tagless
select { case x := <-ch: a; case ch <- v: b; default: c }
AST shapes:
(list :switch TAG CASES) — TAG nil for tagless
(list :case VALUES BODY) — VALUES is expr-list
(list :select CASES)
(list :select-case COMM-STMT BODY) — COMM-STMT is send/recv-assign/bare-recv
(list :default BODY)
gp-parse-case-body reads stmts until the next case/default/}/eof
without consuming the terminator — used by both switch and select.
select-case parsing reuses gp-parse-stmt for the comm-stmt, so all
four shapes (send, x := <-ch, x = <-ch, bare <-ch) fall out from the
existing stmt parser. Composite-lit suppression is engaged for the
switch tag expression.
Type-switch (`switch v := x.(type) { case int: ... }`) is the one
deferred shape; needs the `.(type)` pseudo-syntax recognised in the
expression layer. Phase 2 statement coverage is otherwise complete.
This is also a chiselling iteration for scheduler sister kit. Diary
updated with select-case design insights:
* All four select-case shapes share (list :select-case STMT BODY)
— kit primitive sched-select accepts a uniform list of cases.
* Default vs no-default determines blocking semantics. Erlang's
`receive ... after Timeout -> ...` is the analogue — both fit
"non-blocking fallback case" in the kit API.
parse 169/169, total 298/298.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go's concurrency + iteration primitives to the statement parser:
go EXPR → (list :go EXPR)
defer EXPR → (list :defer EXPR)
ch <- v → (list :send CHAN VALUE)
for range COLL { ... } → (list :range-for nil nil nil COLL BODY)
for k := range C { ... } → (list :range-for :short-decl KEY nil COLL BODY)
for k, v := range C { } → (list :range-for :short-decl KEY VAL COLL BODY)
for k, v = range C { ... } → (list :range-for :assign KEY VAL COLL BODY)
gp-for-find-range pre-scans the for-header (to '{' or eof) looking
for the 'range' keyword; if present, dispatches to gp-parse-for-range
which handles the four range shapes. C-style and while-like and
infinite are now in gp-parse-for-c-style — gp-parse-for is just a
dispatcher.
Send statement detection lives in the LHS-list branch of gp-parse-stmt:
after parsing a single LHS expression, '<-' triggers (:send LHS RHS).
Channel-recv (`<-ch`) was already parsed as unary `<-` in the expression
layer, so both directions cover.
This is the **chiselling-relevant iteration** for the scheduler sister
kit: the AST shapes Go-on-SX will eventually feed into the kit's
scheduler primitives (sched-spawn, sched-defer, chan-op) have landed.
Sister-plan diary updated with three design insights:
* :go / :defer both wrap a single expr — kit's sched-spawn should
accept a thunk uniformly across Erlang's spawn(M,F,A) and Go's
go fn().
* :send carries CHAN+VALUE symmetrically with the unary <- recv —
both reduce to (chan-op direction chan value) in the kit.
* `for v := range ch` uses the same :range-for shape as range-over-
slice; the scheduler kit's range dispatch is where chan-recv ⇄
iteration polymorphism lives.
parse 161/161, total 290/290.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds the most-used control-flow forms:
if COND { ... } [else { ... } | else if ...]
for { ... } — infinite
for COND { ... } — while-like
for INIT; COND; POST { ... } — C-style
break / continue — keyword stmts (no labels yet)
x++ / x-- — Go statement inc-dec
AST shapes:
(list :if COND THEN ELSE) — ELSE nil / :if / :block
(list :for INIT COND POST BODY) — any of INIT/COND/POST may be nil
(list :break LABEL) (list :continue LABEL)
(list :inc-dec OP EXPR) — OP is "++" / "--"
**Closes the parser-mode caveat** logged when composite literals
landed. `gp-no-comp-lit` is a re-entrant counter on the parser state;
control-flow constructs increment it before parsing their condition
and decrement after, suppressing the postfix `{` → composite-lit
interpretation so that `if Foo { ... }` correctly reads `{ ... }` as
the body, not as `Foo{}` composite literal. Verified by the test:
(go-parse "if Foo {}") → (:if (:var "Foo") (:block ()) nil)
gp-parse-control-cond is the single helper that bracket-wraps the
flag bump so future control-flow forms (switch, select, range) can't
forget to engage suppression.
switch / select / defer / go / for-range / channel-send still deferred.
parse 152/152, total 281/281.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
First slice of Phase 2 statements. Replaces the func-decl ':body'
sentinel with real (:block STMTS) parsing.
gp-parse-stmt dispatches on the leading token:
return [exprs] — (list :return EXPRS)
{ ... } — nested block (recurses into block-body)
lhs := exprs — (list :short-decl LHS-LIST EXPRS)
lhs = exprs — (list :assign LHS-LIST EXPRS)
lhs OP= expr — (list :assign-op OP LHS-LIST [EXPR])
expr — bare expression statement
var/const/type/func keywords — fall through to gp-parse-decl
LHS may be a comma-separated list. Compound-assign covers all 11 Go
forms (+= -= *= /= %= &= |= ^= <<= >>= &^=).
gp-parse-block-body iterates: skips semis, terminates on '}', and for
non-trivial tokens calls gp-parse-stmt. **Two progress guards** added
to avoid infinite loops on unsupported syntax:
* gp-block-body-loop force-advances one token if gp-parse-stmt
returns nil without consuming.
* gp-parse-composite-elems does the same when its expr parser
returns nil — fixes a hang on '`if true {`x := 1`}`' where the
parser was misreading `if true{...}` as a composite literal then
spinning on `:=` inside the brace body.
Existing func/method decl tests updated from the ':body' sentinel to
the new (:block STMTS) shape. Old `gp-skip-block!` left as dead code
(removed once control-flow stmts make the misinterpretation issue
moot).
Control-flow stmts (if/for/switch/select/defer/go/break/continue) and
channel send (`ch <- v`) deferred to subsequent iterations.
parse 141/141, total 270/270.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go func and method declarations:
func main() {}
func add(x, y int) int { return x + y }
func mix(x int, y string) {}
func divmod(a, b int) (int, int) {}
func sig(x int) int (no body)
func (p *Point) String() string { ... } (method, pointer recv)
func (s Stack) Len() int { ... } (method, value recv)
func nested() { if true { x := 1; { y := 2 } } } (nested braces)
New gp-parse-decl-param-group implements named-greedy disambiguation:
collects consecutive 'ident [, ident]*' then parses a type. Anonymous
mixed lists like 'func(int, string)' are a known limitation (parser
treats first ident as a name); flagged in plan.
gp-skip-block! brace-balances over the body; the AST stores ':body'
as a sentinel until statement parsing lands. Methods use the receiver
parameter shape directly.
AST:
(list :func-decl NAME PARAMS RESULTS BODY)
(list :method-decl RECV NAME PARAMS RESULTS BODY)
**All five `:field` binding-group consumers now exist** across the
parser: struct fields, var, const, func params, method receivers.
That's strong cross-deliverable validation of the ast-binding-group
proposal from Blockers — five different declaration contexts, one
shared shape.
This is the chisel-relevant insight for sister plan static-types-
bidirectional: an entry has been appended to its design diary
describing how `:field` will be the load-bearing input shape for
the bidirectional checker's `check Γ e T` judgment across these
contexts.
parse 132/132, total 261/261.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
First slice of Phase 2 declarations:
package main → (list :package "main")
import "fmt" → (ast-import "fmt") [from kit]
var x int → var-decl + :field binding
var x = 5 → init only (type inferred)
var x int = 5 → both type and init
var x, y int = 1, 2 → multi-name shared type
const Pi = 3.14 → const-decl
const C int = 42 → typed const
type T int → named alias
type Point struct { x, y int } → named struct
New gp-parse-top dispatches on the leading keyword: routes
package/import/var/const/type to gp-parse-decl; everything else
still goes through gp-parse-expr. Existing expression tests are
unaffected (cur won't be a decl keyword at expression start).
var/const decls use the (:field NAMES TYPE) shape from the
ast-binding-group proposal — first concrete cross-deliverable use:
struct fields, var decls, const decls all envelope through the
same node. That's the smell test for whether the kit shape is
right; so far it's clean.
import uses the canonical ast-import from lib/guest/ast.sx — first
direct use of a kit constructor for a declaration shape.
Grouped/parenthesized decls (var (...), import (...), const (...),
type (...)) and func decls (with method receivers + named params)
deferred to subsequent iterations.
parse 124/124, total 253/253.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go composite literals:
T{} empty
T{1, 2} positional
T{X: 1, Y: 2} keyed
[]int{1, 2, 3} slice
[3]int{1, 2, 3} array
map[string]int{"a": 1} map
pkg.Point{1, 2} qualified
[]Point{Point{1,2}, Point{3,4}} nested
AST: (list :composite TYPE-OR-EXPR ELEMS). Each element is an
expression or (list :kv KEY VALUE).
Two parser entry points feed the same AST:
* gp-parse-primary picks up type-prefixed composites by seeing
a literal-type starter ([, map, struct) and parsing a type
first, then optionally a '{' body.
* The postfix loop picks up ident-prefixed composites — after
any base expression, '{' wraps it as a composite literal.
Known limitation flagged in plan: when statement parsing arrives,
the postfix '{' branch will misread `if cond { ... }` as a composite
literal. Standard fix: parser-mode flag suppressing composite-lit
disambiguation in control-flow expression positions. Added to plan.
Elided types in nested composites (`[][]int{{1,2},{3,4}}` with the
inner `{1,2}` typed implicitly) deferred.
parse 114/114, total 243/243.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go interface type expressions:
interface {} → empty
interface { Close() } → no-param method
interface { String() string } → with single return
interface { Read([]byte) (int, error) } → multi-return method
interface { Stringer } → embedded named iface
interface { io.Reader } → qualified embedded
interface { io.Reader; Close() error } → mixed
gp-parse-interface-elems walks elements tolerating ASI semis. Each
element is either:
(list :method NAME PARAMS RESULTS)
(list :embed TYPE)
Method params/results reuse gp-parse-func-type-params/results — the
shape is identical to a free-standing func type. Go 1.18+ type sets
(interface { ~int | ~float64 }) are deferred until the generics
sub-deliverable.
With this, the full Phase 2 **type expressions** sub-deliverable is
complete (pending only field tags, struct/iface embeds details,
variadic, named func params, generics — all flagged later).
parse 106/106, total 235/235.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go struct types to gp-parse-type:
struct {} → (list :ty-struct ())
struct { x int } → (list :ty-struct [(:field [x] (:ty-name int))])
struct { x int; y string } → multiple field rows
struct { x, y int } → shared-type row (NAMES is a list)
struct { inner struct { x int } } → nested struct types
gp-parse-struct-fields walks field rows tolerating ASI-inserted semis
(from newlines between fields). Each row collects 1+ names separated
by commas, then a single type that all the names share. Embedded
fields, field tags, and methods are deferred.
The :field shape (NAMES + TYPE) is a recurring multi-language pattern —
struct fields, func params, method receivers, var decls all map to it.
Logged in Blockers as a canonical-AST candidate
(ast-binding-group / ast-named-of-type); worth promoting once a second
consumer (parser of another statically-typed guest, or Go func decls)
exercises the same shape.
parse 98/98, total 227/227.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go func-type parsing to gp-parse-type:
func() → (list :ty-func () ())
func() int → (list :ty-func () [int])
func(int, string) → (list :ty-func [int string] ())
func(int) string → (list :ty-func [int] [string])
func() (int, error) → (list :ty-func () [int error])
gp-parse-func-type-params handles the param list inside (...);
gp-parse-func-type-results dispatches between bare single-return,
multi-return parenthesised list, or no return.
Anonymous-only — named params (`func(a int, b string)`) require a
different shape and are mainly needed for func DECLARATIONS, not for
pure func-type expressions in type position. Variadic ('...T')
deferred.
Covers nested cases: func returning func, chan of func, func with
pointer/slice operands.
parse 90/90, total 219/219.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds the bulk of Go's type-expression grammar:
[]T → (list :ty-slice T)
[N]T → (list :ty-array N T) — N is an expr
map[K]V → (list :ty-map K V)
chan T → (list :ty-chan :both T)
chan<- T → (list :ty-chan :send T)
<-chan T → (list :ty-chan :recv T)
gp-parse-type now dispatches on the head token: *, [, map, chan, <-,
or ident; each branch recurses for nested types. Channel direction
is encoded as :both / :send / :recv (Go-specific tag).
Coverage: nested types end-to-end — []*T, [][]int, map[string][]int,
chan map[K]V, *[]int — all via the v.(T) assertion carrier.
Logged a concrete kit-gap proposal in plans/go-on-sx.md Blockers for
canonical type-node shapes. The first six (:ty-name, :ty-sel, :ty-ptr,
:ty-slice, :ty-array, :ty-map) are universal across statically-typed
guests and worth promoting on the next consumer; channel/func shapes
stay guest-specific until a second user.
Phase 2 parse acceptance bar (80+ tests) crossed: parse 81/81, total
210/210. Func / struct / interface types and full decls + stmts still
keep Phase 2 open.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Postfix '.' branch now peeks at the next token to disambiguate:
.ident → selector / member access (list :select OBJ "field")
.(TYPE) → type assertion (list :assert OBJ TYPE)
New gp-parse-type covers the minimum types needed for assertions:
name → (list :ty-name "int")
pkg.Name → (list :ty-sel "pkg" "Name")
*T / **T → (list :ty-ptr (list :ty-ptr ...))
Full type grammar — slice []T, array [N]T, map[K]V, chan, func,
struct, interface — is a separate Phase 2 sub-deliverable.
Type AST shapes are Go-specific tagged lists; the canonical AST kit
has no type-system primitives at all yet. Worth a richer kit
discussion once Phase 3 (bidirectional type checker) lands and the
sister plan static-types-bidirectional has a real surface to react to.
parse 70/70, total 199/199.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds the bracket postfix branch:
a[0] / a[i] / a[i+1] / m["key"] → (list :index OBJ IDX)
a[:] / a[1:] / a[:2] / a[1:2] / a[1:2:3] → (list :slice OBJ LOW HIGH MAX)
LOW/HIGH/MAX are AST nodes or nil for omitted indices. The 4th MAX
slot is only populated by the three-index full-slice form.
Two new lib/guest/ast.sx kit gaps surfaced (logged in plans/go-on-sx.md
Blockers):
* No :index node — universal across guests with arrays/maps.
* No :slice node — Python/Rust/Swift/JS/Ruby all need at minimum the
two-index form. Go's three-index variant is more specialised but
fits in the same shape with an optional fourth slot.
Parser is permissive on a[1::3] (strict Go rejects, but the type phase
can enforce the grammar; lexer/parser stays loose).
Chained (a[0][1]) and mixed-with-selector (a[0].field) cases work via
the existing left-associative postfix loop.
parse 61/61, total 190/190.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds postfix expression forms per Go spec:
f() f(x) f(x, y, z) — function calls
x.y x.y.z obj.method(x) — selector / member access
gp-parse-postfix sits between gp-parse-unary and gp-parse-primary,
so calls and selectors bind tighter than any unary prefix — `-f(x)`
parses as `-(f(x))`, not `(-f)(x)`. Postfix is left-associative
(`x.y.z` = `(x.y).z`), so the loop iterates rather than recurses
on the LHS.
AST shapes:
Call: (ast-app FN ARGS) — canonical
Selector: (list :select OBJ "field") — Go-specific tag
The selector shape is a kit gap — lib/guest/ast.sx ships ast-app but
no ast-select, despite `obj.field` being universal across Go, Rust,
Swift, TS, JS, Python, Ruby, Java, C#. Logged in Blockers; tagging
[proposes-ast]. Worth promoting on the next nominally-typed guest.
parse 49/49, total 178/178.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go unary prefix operators per Go spec § Operators:
+x -x !x ^x *p &v <-ch
gp-parse-unary is recursive (so !!x and -^x chain correctly) and
sits between gp-parse-expr and gp-parse-primary — unary therefore
always binds tighter than any binary op without needing a unary
entry in the precedence table.
Symbols +, -, *, &, ^ are shared between unary and binary forms;
the positional split (expression-start sees unary, mid-expression
sees binary) disambiguates them cleanly with no lookback.
Unary nodes are single-arg ast-app:
(ast-app (ast-var OP) (list OPERAND))
parse 37/37, total 166/166.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
gp-parse-expr / gp-pratt-loop implement classic Pratt climbing
against go-precedence-table (entry shape from lib/guest/pratt.sx).
The kit gives us pratt-op-lookup + accessors; the climbing loop
itself stays per-language (per kit header — Lua and Prolog have
opposite conventions).
Left-associative ops raise the right-recursion min by 1; right-
associative would keep prec. All Go binary operators are left-assoc.
AST shape: a binary node is emitted as
(ast-app (ast-var OP) [LHS RHS])
— canonical ast-app rather than a Go-specific binary node, since a
future evaluator can recognise operator-named apps without losing
information.
Coverage: equal-prec left-to-right, * tighter than +, && tighter
than ||, comparison tighter than &&, long left-assoc chains, mixed
literal+ident operands.
parse 26/26, total 155/155.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Starts Phase 2. lib/go/parse.sx defines:
* go-precedence-table — Go's five operator-precedence levels in the
(NAME PREC ASSOC) entry shape from lib/guest/pratt.sx, ready for the
binary-operator iteration to consume via pratt-op-lookup.
* go-parse(src) — tokenises and parses ONE primary expression: int,
float, imag, string, rune literals become (ast-literal VALUE);
identifiers become (ast-var NAME). Built directly on lib/guest/ast.sx
constructors — no intermediate AST shape.
Conformance.sh extended to load lib/guest/{ast,pratt}.sx and run the
new parse suite. Scoreboard cleanup: drop the "pending" parse row since
the suite is now real.
parse 17/17 (lex still 129/129). Total 146/146.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds the missing tilde operator '~' (Go 1.18+ generics type-set
constraint, e.g. 'interface { ~int | ~float64 }') to the longest-match
operator table. Adds an exhaustive 'op-audit:' test block covering
every Go operator/punctuation token by category — arithmetic +
assignment, bitwise + assignment, comparison + logical, decls /
arrows / variadic / inc-dec, punctuation, and tilde.
Phase 1 (tokenizer) is now complete. Two kit gaps surfaced and logged
in plans/go-on-sx.md Blockers for the substrate maintainer / next
statically-typed guest loop:
* lib/guest/lex.sx lacks lex-oct-digit? / lex-bin-digit?
(we rolled local gl-* equivalents for 0o.. and 0b.. literals).
* lib/guest/lex.sx lacks a table-driven longest-prefix operator
matcher; our gl-match-op is a 25-clause cond ladder. Rust/Swift/TS
will each hit the same shape with 50+ ops apiece.
lex 129/129. Phase 2 (parser) next.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go raw string literals per Go spec § String literals:
backtick-delimited, no escape processing, may span multiple
lines, '\r' chars discarded from the value.
gl-read-raw-string! mirrors gl-read-string! but skips escape
handling and the \r filter. scan! routes the leading backtick
to it; emits "string" type (same as interpreted strings — no
need to distinguish at parse/type time).
lex 123/123.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds Go float and imaginary literal forms per Go spec § Floating-point
literals and § Imaginary literals:
3.14 .5 1. 1e10 1.5e-3 2.0e+2 1E5 (floats)
2i 3.14i 1e2i (imag)
gl-read-number! returns one of "int" / "float" / "imag"; gl-finish-number!
factors out the post-mantissa exponent + 'i' suffix logic so the int /
float / leading-dot-float paths all share it. scan! adds a .<digit>
branch ahead of the operator matcher so '.5' tokenises as float.
ASI trigger list extended to include float + imag (Go spec § Semicolons:
all literal types trigger).
Greedy-grammar pin (a single test '1.method' lexes as float ident),
since the Go spec says the '.' after a digit always belongs to the
number, never to a following identifier.
Hex floats (0x1.fp0) deferred — not commonly used.
lex 114/114.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds prefixed integer forms per Go spec § Integer literals:
0x.. / 0X.. (hex), 0b.. / 0B.. (binary), 0o.. / 0O.. (octal),
legacy 0123 octal also accepted. Underscores allowed between digits
in any run; lexer is permissive (parser/types phase can enforce
strict placement).
Dispatch lives in gl-read-number! against the first 1-2 chars;
hex digit run consumes lex-hex-digit? from lib/guest/lex.sx. Octal
and binary use local gl-oct-digit?/gl-bin-digit? — narrow enough
that promoting them to the kit is premature.
lex 92/92.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
First Go-on-SX iteration. Tokenizer consumes lib/guest/lex.sx character-class
predicates. Automatic semicolon insertion per Go spec § Semicolons fires on
newline, EOF, and block comments containing a newline, after
ident/int/string/rune/{break,continue,fallthrough,return}/{++,--,),],}}.
Scoreboard + conformance.sh wired; lex 78/78. Plan Phase 1 sub-items
checked; floats/raw-strings/hex-ints still ⬜.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
- go-on-sx.md: rewrite of 2026-04-26 draft to integrate lib/guest framework.
Adds Phase 3 (independent bidirectional type checker — first static-typed
guest), Phase 10 (extraction enabler), chisel discipline, conformance
scoreboard model. Phases 1-2 now consume lib/guest/core lex+pratt+ast.
- lib-guest-scheduler.md: NEW. Extraction plan for the fork/yield/block/
resume scheduler shared by Erlang (addressed processes + mailboxes) and
Go (anonymous channels + goroutines). Two-language rule blocks extraction
until both consumers independently work; rejected-extraction is a valid
outcome.
- lib-guest-static-types-bidirectional.md: NEW. Sister to lib/guest/hm.sx.
Bidirectional checker kit (synth/check judgments, pluggable subtype +
unify) for the languages HM doesn't fit — Go, Rust, TS, Swift, Kotlin,
Scala 3, Hack. First consumer: Go-on-SX. Second TBD; recommendation
TypeScript.
The three plans cross-reference each other. Go-on-SX implements scheduler +
checker independently of the kits; extraction is its own workstream once
two consumers exist.
