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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>
975 lines
40 KiB
Plaintext
975 lines
40 KiB
Plaintext
;; lib/go/parse.sx — Go parser. Tokenises via go-tokenize (lib/go/lex.sx),
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;; builds canonical AST nodes per lib/guest/ast.sx, and uses
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;; pratt-op-lookup from lib/guest/pratt.sx for operator-precedence climbing.
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;;
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;; Slices so far:
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;; 1. Primary expressions — literal / identifier → ast-literal / ast-var
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;; 2. Binary operators — Pratt precedence climbing against
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;; go-precedence-table; binary application
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;; emitted as (ast-app (ast-var OP) [LHS RHS]).
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;;
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;; The climbing loop is per-language (see lib/guest/pratt.sx header on why)
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;; but the entry shape and lookup are shared.
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;;
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;; All scanner locals are gp- prefixed: SX host primitives silently shadow
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;; guest-language defines.
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(define
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go-precedence-table
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(list
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(list "*" 5 :left)
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(list "/" 5 :left)
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(list "%" 5 :left)
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(list "<<" 5 :left)
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(list ">>" 5 :left)
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(list "&" 5 :left)
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(list "&^" 5 :left)
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(list "+" 4 :left)
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(list "-" 4 :left)
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(list "|" 4 :left)
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(list "^" 4 :left)
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(list "==" 3 :left)
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(list "!=" 3 :left)
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(list "<" 3 :left)
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(list "<=" 3 :left)
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(list ">" 3 :left)
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(list ">=" 3 :left)
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(list "&&" 2 :left)
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(list "||" 1 :left)))
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(define
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go-parse
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(fn
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(src)
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(let
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((gp-tokens (go-tokenize src)) (gp-idx 0) (gp-no-comp-lit 0))
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(define gp-cur (fn () (nth gp-tokens gp-idx)))
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(define gp-advance! (fn () (set! gp-idx (+ gp-idx 1))))
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(define gp-tok-type (fn () (get (gp-cur) :type)))
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(define gp-tok-value (fn () (get (gp-cur) :value)))
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(define
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gp-parse-primary
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(fn
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()
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(let
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((ty (gp-tok-type)) (v (gp-tok-value)))
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(cond
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(or
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(= ty "int")
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(= ty "float")
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(= ty "imag")
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(= ty "string")
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(= ty "rune"))
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(do (gp-advance!) (ast-literal v))
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(= ty "ident")
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(do (gp-advance!) (ast-var v))
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;; Type-prefixed composite literal starters: [, map, struct.
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;; We parse a full type, then if '{' follows it's a composite
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;; literal; otherwise the type is the operand (the caller
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;; decides what to do — currently statement parsing isn't here).
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(or (and (= ty "op") (= v "["))
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(and (= ty "keyword")
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(or (= v "map") (= v "struct"))))
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(let ((tytree (gp-parse-type)))
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
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(do
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(gp-advance!)
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(list :composite tytree (gp-parse-composite-elems)))
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:else tytree))
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:else nil))))
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(define
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gp-parse-composite-elems
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;; Caller has consumed '{'. Parses elements until '}'.
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;; Each element: either an expression, or KEY ':' VALUE.
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;; KEY can be an ident (struct field name) or an expression
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;; (map key) — parser is permissive, types phase disambiguates.
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;; Returns a list of expression nodes or (list :kv KEY VALUE).
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(fn
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()
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(let ((elems (list)))
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(define
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gp-comp-loop
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(fn
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()
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(cond
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(= (gp-tok-type) "semi")
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(do (gp-advance!) (gp-comp-loop))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "}"))
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(gp-advance!)
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:else
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(do
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(let ((saved-idx gp-idx))
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(let ((first (gp-parse-expr 1)))
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(cond
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(and (= (gp-tok-type) "op")
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(= (gp-tok-value) ":"))
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(do
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(gp-advance!)
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(let ((val (gp-parse-expr 1)))
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(append! elems (list :kv first val))))
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:else
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(when (not (= first nil))
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(append! elems first))))
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(when (and (= (gp-tok-type) "op")
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(= (gp-tok-value) ","))
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(gp-advance!))
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(when (= gp-idx saved-idx) (gp-advance!)))
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(gp-comp-loop)))))
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(gp-comp-loop)
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elems)))
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(define
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gp-parse-call-args
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;; Parse comma-separated args inside (...). Caller has already
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;; consumed the opening "(". Consumes the closing ")".
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;; Returns a list of argument AST nodes.
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(fn
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()
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(let ((args (list)))
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) ")"))
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(do (gp-advance!) args)
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:else
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(do
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(let ((first (gp-parse-expr 1)))
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(when (not (= first nil)) (append! args first)))
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(define
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gp-args-rest
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(fn
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()
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) ","))
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(do
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(gp-advance!)
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(let ((arg (gp-parse-expr 1)))
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(when (not (= arg nil)) (append! args arg)))
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(gp-args-rest))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) ")"))
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(gp-advance!)
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:else nil)))
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(gp-args-rest)
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args)))))
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(define
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gp-parse-interface-elems
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;; Caller positioned BEFORE '{'. Parses elements until '}'.
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;; Two element shapes:
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;; M(params) [results] → (list :method "M" PARAMS RESULTS)
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;; T or pkg.T → (list :embed TYPE)
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;; Type sets (Go 1.18+: ~int | ~float64) deferred.
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(fn
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()
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(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
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(gp-advance!))
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(let ((elems (list)))
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(define
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gp-iface-loop
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(fn
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()
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(cond
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(= (gp-tok-type) "semi")
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(do (gp-advance!) (gp-iface-loop))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "}"))
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(gp-advance!)
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(= (gp-tok-type) "ident")
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(do
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(let ((name (gp-tok-value)))
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(gp-advance!)
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(cond
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(and (= (gp-tok-type) "op")
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(= (gp-tok-value) "("))
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(let ((params (gp-parse-func-type-params)))
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(let ((results (gp-parse-func-type-results)))
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(append! elems
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(list :method name params results))))
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(and (= (gp-tok-type) "op")
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(= (gp-tok-value) "."))
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(do
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(gp-advance!)
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(cond
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(= (gp-tok-type) "ident")
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(let ((sel-name (gp-tok-value)))
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(gp-advance!)
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(append! elems
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(list :embed
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(list :ty-sel name sel-name))))
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:else
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(append! elems
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(list :embed (list :ty-name name)))))
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:else
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(append! elems (list :embed (list :ty-name name)))))
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(gp-iface-loop))
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:else nil)))
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(gp-iface-loop)
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elems)))
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(define
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gp-parse-struct-fields
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;; Caller positioned BEFORE '{'. Parses fields until '}'.
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;; field := name [, name]* TYPE
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;; Tolerates ASI-inserted semis between fields. Embedded fields
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;; (anonymous type without preceding names) and field tags are
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;; deferred. Returns a list of (list :field NAMES TYPE).
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(fn
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()
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(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
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(gp-advance!))
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(let ((fields (list)))
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(define
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gp-struct-loop
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(fn
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()
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(cond
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(= (gp-tok-type) "semi")
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(do (gp-advance!) (gp-struct-loop))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "}"))
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(gp-advance!)
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(= (gp-tok-type) "ident")
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(do
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(let ((names (list (gp-tok-value))))
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(gp-advance!)
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(define
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gp-names-rest
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(fn
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()
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(when (and (= (gp-tok-type) "op")
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(= (gp-tok-value) ","))
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(gp-advance!)
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(when (= (gp-tok-type) "ident")
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(append! names (gp-tok-value))
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(gp-advance!))
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(gp-names-rest))))
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(gp-names-rest)
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(let ((ty (gp-parse-type)))
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(append! fields (list :field names ty))))
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(gp-struct-loop))
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:else nil)))
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(gp-struct-loop)
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fields)))
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(define
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gp-parse-func-type-params
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;; Anonymous-only func-type params: caller is positioned BEFORE
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;; the opening "(". Returns a list of type AST nodes.
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;; Named params (a int, b string) are deferred — they're needed
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;; for func DECLARATIONS, not pure func-type expressions.
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(fn
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()
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(let ((params (list)))
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(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "("))
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(gp-advance!))
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) ")"))
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(do (gp-advance!) params)
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:else
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(do
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(let ((first (gp-parse-type)))
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(when (not (= first nil)) (append! params first)))
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(define
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gp-params-rest
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(fn
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()
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) ","))
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(do
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(gp-advance!)
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(let ((t (gp-parse-type)))
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(when (not (= t nil)) (append! params t)))
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(gp-params-rest))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) ")"))
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(gp-advance!)
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:else nil)))
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(gp-params-rest)
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params)))))
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(define
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gp-parse-func-type-results
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;; Zero, one, or many return types. Caller is positioned after
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;; the closing ')' of params.
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;; no return — next token is not a type-starter
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;; single return — bare type follows
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;; multi return — '(' T, T, ... ')'
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(fn
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()
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "("))
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(gp-parse-func-type-params)
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:else
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(let ((t (gp-parse-type)))
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(cond
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(= t nil) (list)
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:else (list t))))))
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(define
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gp-parse-type
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;; Go type-expression parser. Covers:
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;; *T → (list :ty-ptr T)
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;; name → (list :ty-name "name")
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;; pkg.Name → (list :ty-sel "pkg" "Name")
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;; []T → (list :ty-slice T)
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;; [N]T → (list :ty-array N T)
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;; map[K]V → (list :ty-map K V)
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;; chan T → (list :ty-chan :both T)
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;; chan<- T → (list :ty-chan :send T)
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;; <-chan T → (list :ty-chan :recv T)
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;; Struct, interface, func types are deferred to a later slice.
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(fn
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()
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "*"))
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(do (gp-advance!) (list :ty-ptr (gp-parse-type)))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "["))
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(do
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(gp-advance!)
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "]"))
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(do (gp-advance!) (list :ty-slice (gp-parse-type)))
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:else
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(let ((sz (gp-parse-expr 1)))
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(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "]"))
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(gp-advance!))
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(list :ty-array sz (gp-parse-type)))))
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(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "map"))
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(do
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(gp-advance!)
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(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "["))
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(gp-advance!))
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(let ((k (gp-parse-type)))
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(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "]"))
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(gp-advance!))
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(let ((v (gp-parse-type)))
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(list :ty-map k v))))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "<-"))
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(do
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(gp-advance!)
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(when (and (= (gp-tok-type) "keyword") (= (gp-tok-value) "chan"))
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(gp-advance!))
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(list :ty-chan :recv (gp-parse-type)))
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(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "chan"))
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(do
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(gp-advance!)
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "<-"))
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(do (gp-advance!) (list :ty-chan :send (gp-parse-type)))
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:else (list :ty-chan :both (gp-parse-type))))
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(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "func"))
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(do
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(gp-advance!)
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(let ((params (gp-parse-func-type-params)))
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(let ((results (gp-parse-func-type-results)))
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(list :ty-func params results))))
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(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "struct"))
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(do
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(gp-advance!)
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(list :ty-struct (gp-parse-struct-fields)))
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(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "interface"))
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(do
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(gp-advance!)
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(list :ty-interface (gp-parse-interface-elems)))
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(= (gp-tok-type) "ident")
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(let ((name (gp-tok-value)))
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(gp-advance!)
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "."))
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(do
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(gp-advance!)
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(cond
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(= (gp-tok-type) "ident")
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(let ((sel-name (gp-tok-value)))
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(gp-advance!)
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(list :ty-sel name sel-name))
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:else (list :ty-name name)))
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:else (list :ty-name name)))
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:else nil)))
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(define
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gp-parse-bracket-expr
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;; Optional expression inside brackets — returns nil if next token
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;; is ':' or ']' (the slice "omitted" cases).
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(fn
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()
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(cond
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(and (= (gp-tok-type) "op")
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(or (= (gp-tok-value) ":") (= (gp-tok-value) "]")))
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nil
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:else (gp-parse-expr 1))))
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(define
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gp-parse-bracket
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;; Caller has consumed '['. Parses index or slice and ']'.
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;; x[i] → (list :index BASE i)
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;; x[a:b] → (list :slice BASE LOW HIGH nil) (LOW/HIGH may be nil)
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;; x[a:b:c] → (list :slice BASE LOW HIGH MAX)
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;; Returns the AST node based on BASE.
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(fn
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(base)
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(let ((low (gp-parse-bracket-expr)))
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "]"))
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(do (gp-advance!) (list :index base low))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) ":"))
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|
(do
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|
(gp-advance!)
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(let ((high (gp-parse-bracket-expr)))
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(cond
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(and (= (gp-tok-type) "op") (= (gp-tok-value) "]"))
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(do (gp-advance!) (list :slice base low high nil))
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(and (= (gp-tok-type) "op") (= (gp-tok-value) ":"))
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(do
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(gp-advance!)
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(let ((maxe (gp-parse-bracket-expr)))
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(when (and (= (gp-tok-type) "op")
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(= (gp-tok-value) "]"))
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(gp-advance!))
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(list :slice base low high maxe)))
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:else (list :slice base low high nil))))
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:else base))))
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(define
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gp-parse-postfix
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;; Left-associative postfix loop on top of gp-parse-primary:
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;; x.field → (list :select x "field") — Go-specific
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;; f(args...) → (ast-app f args) — canonical
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;; x[i] → (list :index x i) — Go-specific
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;; x[a:b] → (list :slice x low high max) — Go-specific
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|
(fn
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()
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(let ((base (gp-parse-primary)))
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(gp-postfix-loop base))))
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|
(define
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gp-postfix-loop
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|
(fn
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|
(base)
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(cond
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|
(= base nil) nil
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|
:else
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|
(let ((tok (gp-cur)))
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|
(cond
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|
(and (= (get tok :type) "op") (= (get tok :value) "."))
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|
(do
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|
(gp-advance!)
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|
(let ((next-tok (gp-cur)))
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|
(cond
|
|
;; .(T) — type assertion
|
|
(and (= (get next-tok :type) "op")
|
|
(= (get next-tok :value) "("))
|
|
(do
|
|
(gp-advance!)
|
|
(let ((ty (gp-parse-type)))
|
|
(when (and (= (gp-tok-type) "op")
|
|
(= (gp-tok-value) ")"))
|
|
(gp-advance!))
|
|
(gp-postfix-loop (list :assert base ty))))
|
|
;; .ident — selector / member access
|
|
(= (get next-tok :type) "ident")
|
|
(do
|
|
(gp-advance!)
|
|
(gp-postfix-loop
|
|
(list :select base (get next-tok :value))))
|
|
:else base)))
|
|
(and (= (get tok :type) "op") (= (get tok :value) "("))
|
|
(do
|
|
(gp-advance!)
|
|
(gp-postfix-loop (ast-app base (gp-parse-call-args))))
|
|
(and (= (get tok :type) "op") (= (get tok :value) "["))
|
|
(do
|
|
(gp-advance!)
|
|
(gp-postfix-loop (gp-parse-bracket base)))
|
|
;; Ident-prefixed composite literal: T{...}. The base is
|
|
;; the AST expression for the type-name (an ast-var or a
|
|
;; :select node); a later phase resolves it as a type.
|
|
;; SUPPRESSED inside control-flow conditions (if/for/switch)
|
|
;; — Go spec: top-level composite literals must be parenthesised
|
|
;; in those positions. gp-no-comp-lit acts as a re-entrant
|
|
;; counter so nested constructs nest correctly.
|
|
(and (= (get tok :type) "op") (= (get tok :value) "{")
|
|
(= gp-no-comp-lit 0))
|
|
(do
|
|
(gp-advance!)
|
|
(gp-postfix-loop
|
|
(list :composite base (gp-parse-composite-elems))))
|
|
:else base)))))
|
|
(define
|
|
gp-unary-ops
|
|
;; Go spec § Operators: prefix unary, all higher precedence than
|
|
;; any binary operator. <- is the channel receive form (send is a
|
|
;; statement, not an expression, so never appears here as binary).
|
|
(list "+" "-" "!" "^" "*" "&" "<-"))
|
|
(define
|
|
gp-parse-unary
|
|
(fn
|
|
()
|
|
(let ((tok (gp-cur)))
|
|
(cond
|
|
(and (= (get tok :type) "op")
|
|
(some (fn (u) (= u (get tok :value))) gp-unary-ops))
|
|
(do
|
|
(gp-advance!)
|
|
(let ((operand (gp-parse-unary)))
|
|
(cond
|
|
(= operand nil) nil
|
|
:else (ast-app (ast-var (get tok :value)) (list operand)))))
|
|
:else (gp-parse-postfix)))))
|
|
(define
|
|
gp-parse-expr
|
|
(fn
|
|
(min-prec)
|
|
(let ((left (gp-parse-unary))) (gp-pratt-loop left min-prec))))
|
|
(define
|
|
gp-pratt-loop
|
|
(fn
|
|
(left min-prec)
|
|
(cond
|
|
(= left nil) nil
|
|
:else
|
|
(let
|
|
((tok (gp-cur)))
|
|
(cond
|
|
(not (= (get tok :type) "op"))
|
|
left
|
|
:else (let
|
|
((entry (pratt-op-lookup go-precedence-table (get tok :value))))
|
|
(cond
|
|
(= entry nil)
|
|
left
|
|
(< (pratt-op-prec entry) min-prec)
|
|
left
|
|
:else (do
|
|
(gp-advance!)
|
|
(let
|
|
((next-min (if (= (pratt-op-assoc entry) :left) (+ (pratt-op-prec entry) 1) (pratt-op-prec entry))))
|
|
(let
|
|
((right (gp-parse-expr next-min)))
|
|
(gp-pratt-loop
|
|
(ast-app
|
|
(ast-var (get tok :value))
|
|
(list left right))
|
|
min-prec)))))))))))
|
|
(define
|
|
gp-parse-expr-list
|
|
;; Comma-separated expressions; reused by var/const initialisers.
|
|
(fn
|
|
()
|
|
(let ((exprs (list)))
|
|
(let ((first (gp-parse-expr 1)))
|
|
(when (not (= first nil)) (append! exprs first)))
|
|
(define
|
|
gp-exprs-rest
|
|
(fn
|
|
()
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) ","))
|
|
(gp-advance!)
|
|
(let ((e (gp-parse-expr 1)))
|
|
(when (not (= e nil)) (append! exprs e)))
|
|
(gp-exprs-rest))))
|
|
(gp-exprs-rest)
|
|
exprs)))
|
|
(define
|
|
gp-parse-var-or-const
|
|
;; Caller has consumed 'var' or 'const'. TAG is :var-decl or :const-decl.
|
|
;; Shape: TAG (list :field NAMES TYPE-OR-NIL) EXPRS-OR-NIL
|
|
;; Both type and init are optional (must have at least one in Go;
|
|
;; lexer is permissive).
|
|
(fn
|
|
(tag)
|
|
(let ((names (list)))
|
|
(when (= (gp-tok-type) "ident")
|
|
(append! names (gp-tok-value))
|
|
(gp-advance!))
|
|
(define
|
|
gp-names-rest
|
|
(fn
|
|
()
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) ","))
|
|
(gp-advance!)
|
|
(when (= (gp-tok-type) "ident")
|
|
(append! names (gp-tok-value))
|
|
(gp-advance!))
|
|
(gp-names-rest))))
|
|
(gp-names-rest)
|
|
(let ((ty nil) (exprs nil))
|
|
(when (and (not (= (gp-tok-type) "eof"))
|
|
(not (= (gp-tok-type) "semi"))
|
|
(not (and (= (gp-tok-type) "op")
|
|
(= (gp-tok-value) "="))))
|
|
(set! ty (gp-parse-type)))
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "="))
|
|
(gp-advance!)
|
|
(set! exprs (gp-parse-expr-list)))
|
|
(list tag (list :field names ty) exprs)))))
|
|
(define
|
|
gp-parse-type-decl
|
|
;; Caller has consumed 'type'. Single-decl form only:
|
|
;; type NAME TYPE → (list :type-decl "NAME" TYPE)
|
|
(fn
|
|
()
|
|
(cond
|
|
(= (gp-tok-type) "ident")
|
|
(let ((name (gp-tok-value)))
|
|
(gp-advance!)
|
|
(let ((t (gp-parse-type)))
|
|
(list :type-decl name t)))
|
|
:else nil)))
|
|
(define
|
|
gp-parse-decl-param-group
|
|
;; Parses one parameter binding group inside a func decl param list.
|
|
;; Returns (list :field NAMES TYPE). Named-greedy: collects all
|
|
;; consecutive idents separated by commas, then a type. Fails for
|
|
;; mixed anonymous lists like func(int, string) — flagged in plan.
|
|
(fn
|
|
()
|
|
(cond
|
|
(not (= (gp-tok-type) "ident"))
|
|
(list :field (list) (gp-parse-type))
|
|
:else
|
|
(let ((names (list)) (candidate (gp-tok-value)))
|
|
(gp-advance!)
|
|
(define
|
|
gp-dpg-loop
|
|
(fn
|
|
()
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) ","))
|
|
(let ((saved-idx gp-idx))
|
|
(gp-advance!)
|
|
(cond
|
|
(= (gp-tok-type) "ident")
|
|
(do
|
|
(append! names candidate)
|
|
(set! candidate (gp-tok-value))
|
|
(gp-advance!)
|
|
(gp-dpg-loop))
|
|
:else
|
|
(set! gp-idx saved-idx))))))
|
|
(gp-dpg-loop)
|
|
(cond
|
|
(and (= (gp-tok-type) "op")
|
|
(or (= (gp-tok-value) ")") (= (gp-tok-value) ",")))
|
|
(list :field names (list :ty-name candidate))
|
|
:else
|
|
(do
|
|
(append! names candidate)
|
|
(list :field names (gp-parse-type))))))))
|
|
(define
|
|
gp-parse-func-decl-params
|
|
;; Func-decl parameter list — comma-separated binding groups.
|
|
;; Caller positioned BEFORE '('. Consumes ')'.
|
|
(fn
|
|
()
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "("))
|
|
(gp-advance!))
|
|
(let ((groups (list)))
|
|
(cond
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) ")"))
|
|
(do (gp-advance!) groups)
|
|
:else
|
|
(do
|
|
(append! groups (gp-parse-decl-param-group))
|
|
(define
|
|
gp-fdp-rest
|
|
(fn
|
|
()
|
|
(cond
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) ","))
|
|
(do
|
|
(gp-advance!)
|
|
(append! groups (gp-parse-decl-param-group))
|
|
(gp-fdp-rest))
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) ")"))
|
|
(gp-advance!)
|
|
:else nil)))
|
|
(gp-fdp-rest)
|
|
groups)))))
|
|
(define
|
|
gp-skip-block!
|
|
;; Brace-balanced skip. Caller has consumed the opening '{'.
|
|
;; Statement parsing arrives in a later iteration; for now the
|
|
;; body is opaque and stored as the keyword :body in the AST.
|
|
(fn
|
|
()
|
|
(let ((depth 1))
|
|
(define
|
|
gp-block-loop
|
|
(fn
|
|
()
|
|
(cond
|
|
(= (gp-tok-type) "eof") nil
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
|
|
(do (set! depth (+ depth 1)) (gp-advance!) (gp-block-loop))
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) "}"))
|
|
(do
|
|
(set! depth (- depth 1))
|
|
(gp-advance!)
|
|
(when (> depth 0) (gp-block-loop)))
|
|
:else (do (gp-advance!) (gp-block-loop)))))
|
|
(gp-block-loop))))
|
|
(define
|
|
gp-parse-func-decl
|
|
;; Caller has consumed 'func'.
|
|
;; func NAME (params) [results] { body }
|
|
;; func (recv) NAME (params) [results] { body } — method
|
|
;; AST:
|
|
;; (list :func-decl NAME PARAMS RESULTS BODY)
|
|
;; (list :method-decl RECV NAME PARAMS RESULTS BODY)
|
|
;; BODY is :body (opaque) if a block was present, else nil.
|
|
(fn
|
|
()
|
|
(let ((recv nil))
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "("))
|
|
(gp-advance!)
|
|
(set! recv (gp-parse-decl-param-group))
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) ")"))
|
|
(gp-advance!)))
|
|
(cond
|
|
(= (gp-tok-type) "ident")
|
|
(let ((name (gp-tok-value)))
|
|
(gp-advance!)
|
|
(let ((params (gp-parse-func-decl-params)))
|
|
(let ((results (gp-parse-func-type-results)))
|
|
(let ((body nil))
|
|
(when (and (= (gp-tok-type) "op")
|
|
(= (gp-tok-value) "{"))
|
|
(gp-advance!)
|
|
(set! body (gp-parse-block-body)))
|
|
(cond
|
|
(= recv nil)
|
|
(list :func-decl name params results body)
|
|
:else
|
|
(list :method-decl recv name params results body))))))
|
|
:else nil))))
|
|
(define
|
|
gp-parse-control-cond
|
|
;; Parses an expression as a control-flow condition with the
|
|
;; composite-literal '{' suppression engaged (Go spec: top-level
|
|
;; composite literals require explicit parens in if/for/switch
|
|
;; condition positions).
|
|
(fn
|
|
()
|
|
(set! gp-no-comp-lit (+ gp-no-comp-lit 1))
|
|
(let ((e (gp-parse-expr 1)))
|
|
(set! gp-no-comp-lit (- gp-no-comp-lit 1))
|
|
e)))
|
|
(define
|
|
gp-parse-if
|
|
;; Caller has consumed 'if'.
|
|
;; if COND { BODY }
|
|
;; if COND { BODY } else { BODY }
|
|
;; if COND { BODY } else if ... (chained, recursive ELSE)
|
|
;; AST: (list :if COND THEN ELSE) where ELSE may be nil, a
|
|
;; nested :if, or a :block.
|
|
(fn
|
|
()
|
|
(let ((cnd (gp-parse-control-cond)) (then nil) (els nil))
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
|
|
(gp-advance!)
|
|
(set! then (gp-parse-block-body)))
|
|
;; Skip ASI semis between } and else
|
|
(when (= (gp-tok-type) "semi") (gp-advance!))
|
|
(when (and (= (gp-tok-type) "keyword") (= (gp-tok-value) "else"))
|
|
(gp-advance!)
|
|
(cond
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "if"))
|
|
(do (gp-advance!) (set! els (gp-parse-if)))
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
|
|
(do (gp-advance!) (set! els (gp-parse-block-body)))))
|
|
(list :if cnd then els))))
|
|
(define
|
|
gp-parse-for
|
|
;; Caller has consumed 'for'.
|
|
;; for { BODY } — infinite
|
|
;; for COND { BODY } — while-like
|
|
;; for INIT; COND; POST { BODY } — C-style
|
|
;; for k, v := range coll { BODY } — deferred (range)
|
|
;; AST: (list :for INIT COND POST BODY); any of INIT/COND/POST may be nil.
|
|
(fn
|
|
()
|
|
(set! gp-no-comp-lit (+ gp-no-comp-lit 1))
|
|
(let ((init nil) (cnd nil) (post nil) (body nil))
|
|
(cond
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
|
|
nil
|
|
:else
|
|
(let ((first (gp-parse-stmt)))
|
|
(cond
|
|
(= (gp-tok-type) "semi")
|
|
(do
|
|
(set! init first)
|
|
(gp-advance!)
|
|
(when (not (and (= (gp-tok-type) "op")
|
|
(= (gp-tok-value) ";")))
|
|
(cond
|
|
(= (gp-tok-type) "semi") nil
|
|
:else (set! cnd (gp-parse-expr 1))))
|
|
(when (= (gp-tok-type) "semi") (gp-advance!))
|
|
(when (not (and (= (gp-tok-type) "op")
|
|
(= (gp-tok-value) "{")))
|
|
(set! post (gp-parse-stmt))))
|
|
:else (set! cnd first))))
|
|
(set! gp-no-comp-lit (- gp-no-comp-lit 1))
|
|
(when (and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
|
|
(gp-advance!)
|
|
(set! body (gp-parse-block-body)))
|
|
(list :for init cnd post body))))
|
|
(define
|
|
gp-stmt-assign-ops
|
|
;; Compound assignment operators per Go spec § Assignment operations.
|
|
(list "+=" "-=" "*=" "/=" "%=" "&=" "|=" "^="
|
|
"<<=" ">>=" "&^="))
|
|
(define
|
|
gp-parse-stmt
|
|
;; Parses one Go statement. Recognises:
|
|
;; return [exprs]
|
|
;; { ... } — nested block
|
|
;; lhs := exprs — short declaration
|
|
;; lhs = exprs — assignment
|
|
;; lhs OP= expr — compound assignment
|
|
;; expr — expression statement
|
|
;; LHS may be a comma-separated list. Block-level declarations
|
|
;; (var/const/type/func) route through gp-parse-decl.
|
|
(fn
|
|
()
|
|
(cond
|
|
(= (gp-tok-type) "semi")
|
|
(do (gp-advance!) (gp-parse-stmt))
|
|
(and (= (gp-tok-type) "keyword")
|
|
(or (= (gp-tok-value) "var") (= (gp-tok-value) "const")
|
|
(= (gp-tok-value) "type") (= (gp-tok-value) "func")))
|
|
(gp-parse-decl)
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "return"))
|
|
(do
|
|
(gp-advance!)
|
|
(cond
|
|
(or (= (gp-tok-type) "semi") (= (gp-tok-type) "eof")
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) "}")))
|
|
(list :return (list))
|
|
:else (list :return (gp-parse-expr-list))))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "break"))
|
|
(do (gp-advance!) (list :break nil))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "continue"))
|
|
(do (gp-advance!) (list :continue nil))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "if"))
|
|
(do (gp-advance!) (gp-parse-if))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "for"))
|
|
(do (gp-advance!) (gp-parse-for))
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) "{"))
|
|
(do (gp-advance!) (gp-parse-block-body))
|
|
:else
|
|
(let ((lhs (gp-parse-expr 1)))
|
|
(cond
|
|
(= lhs nil) nil
|
|
:else
|
|
(let ((lhs-list (list lhs)))
|
|
(define
|
|
gp-stmt-lhs-rest
|
|
(fn
|
|
()
|
|
(when (and (= (gp-tok-type) "op")
|
|
(= (gp-tok-value) ","))
|
|
(gp-advance!)
|
|
(let ((e (gp-parse-expr 1)))
|
|
(when (not (= e nil)) (append! lhs-list e)))
|
|
(gp-stmt-lhs-rest))))
|
|
(gp-stmt-lhs-rest)
|
|
(cond
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) ":="))
|
|
(do (gp-advance!)
|
|
(list :short-decl lhs-list (gp-parse-expr-list)))
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) "="))
|
|
(do (gp-advance!)
|
|
(list :assign lhs-list (gp-parse-expr-list)))
|
|
(and (= (gp-tok-type) "op")
|
|
(some (fn (o) (= o (gp-tok-value)))
|
|
gp-stmt-assign-ops))
|
|
(let ((op (gp-tok-value)))
|
|
(gp-advance!)
|
|
(list :assign-op op lhs-list
|
|
(list (gp-parse-expr 1))))
|
|
(and (= (gp-tok-type) "op")
|
|
(or (= (gp-tok-value) "++")
|
|
(= (gp-tok-value) "--")))
|
|
(let ((op (gp-tok-value)))
|
|
(gp-advance!)
|
|
(list :inc-dec op lhs))
|
|
:else
|
|
;; Plain expression statement — return the single expr.
|
|
;; (If somehow there was a comma chain without =/:=, just
|
|
;; return the first expr; permissive.)
|
|
(cond
|
|
(= (len lhs-list) 1) lhs
|
|
:else lhs))))))))
|
|
(define
|
|
gp-parse-block-body
|
|
;; Caller has consumed '{'. Parses statements (and possibly nested
|
|
;; declarations) until '}'. Returns (list :block STMTS).
|
|
(fn
|
|
()
|
|
(let ((stmts (list)))
|
|
(define
|
|
gp-block-body-loop
|
|
(fn
|
|
()
|
|
(cond
|
|
(= (gp-tok-type) "eof") nil
|
|
(and (= (gp-tok-type) "op") (= (gp-tok-value) "}"))
|
|
(gp-advance!)
|
|
(= (gp-tok-type) "semi")
|
|
(do (gp-advance!) (gp-block-body-loop))
|
|
:else
|
|
(do
|
|
;; Progress guard: if gp-parse-stmt returns nil without
|
|
;; advancing, force one token forward to avoid spinning
|
|
;; on unsupported syntax (e.g., 'if' before stmt parser
|
|
;; learns it). Belt-and-braces against future bugs too.
|
|
(let ((saved-idx gp-idx))
|
|
(let ((s (gp-parse-stmt)))
|
|
(when (not (= s nil)) (append! stmts s)))
|
|
(when (= gp-idx saved-idx) (gp-advance!)))
|
|
(gp-block-body-loop)))))
|
|
(gp-block-body-loop)
|
|
(list :block stmts))))
|
|
(define
|
|
gp-parse-decl
|
|
;; Single declaration: package / import / var / const / type.
|
|
;; Grouped/parenthesized forms and func decls are deferred.
|
|
(fn
|
|
()
|
|
(cond
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "package"))
|
|
(do
|
|
(gp-advance!)
|
|
(cond
|
|
(= (gp-tok-type) "ident")
|
|
(let ((name (gp-tok-value)))
|
|
(gp-advance!)
|
|
(list :package name))
|
|
:else nil))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "import"))
|
|
(do
|
|
(gp-advance!)
|
|
(cond
|
|
(= (gp-tok-type) "string")
|
|
(let ((path (gp-tok-value)))
|
|
(gp-advance!)
|
|
(ast-import path))
|
|
:else nil))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "var"))
|
|
(do (gp-advance!) (gp-parse-var-or-const :var-decl))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "const"))
|
|
(do (gp-advance!) (gp-parse-var-or-const :const-decl))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "type"))
|
|
(do (gp-advance!) (gp-parse-type-decl))
|
|
(and (= (gp-tok-type) "keyword") (= (gp-tok-value) "func"))
|
|
(do (gp-advance!) (gp-parse-func-decl))
|
|
:else nil)))
|
|
(define
|
|
gp-parse-top
|
|
;; Top-level dispatch: declaration keywords go to gp-parse-decl,
|
|
;; everything else is parsed as an expression. ASI semis at the
|
|
;; start are skipped.
|
|
(fn
|
|
()
|
|
(cond
|
|
(= (gp-tok-type) "semi")
|
|
(do (gp-advance!) (gp-parse-top))
|
|
(and (= (gp-tok-type) "keyword")
|
|
(or (= (gp-tok-value) "package")
|
|
(= (gp-tok-value) "import")
|
|
(= (gp-tok-value) "var")
|
|
(= (gp-tok-value) "const")
|
|
(= (gp-tok-value) "type")
|
|
(= (gp-tok-value) "func")))
|
|
(gp-parse-decl)
|
|
:else (gp-parse-stmt))))
|
|
(gp-parse-top))))
|