giles
99753580b4
Salvaged from worktree-agent-* branches killed during sx-tree MCP outage: - lua: tokenizer + parser + phase-2 transpile (~157 tests) - prolog: tokenizer + parser + unification (72 tests, plan update lost to WIP) - forth: phase-1 reader/interpreter + phase-2 colon/VARIABLE (134 tests) - erlang: tokenizer + parser (114 tests) - haskell: tokenizer + parse tests (43 tests) Cherry-picked file contents only, not branch history, to avoid pulling in unrelated ocaml-vm merge commits that were in those branches' bases.
50 lines
1.2 KiB
Plaintext
50 lines
1.2 KiB
Plaintext
;; Core parser helpers — shared by er-parse-expr and er-parse-module.
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;; Everything reads/mutates a parser state dict:
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;; {:toks TOKS :idx INDEX}
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(define er-state-make (fn (toks) {:idx 0 :toks toks}))
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(define
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er-peek
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(fn
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(st offset)
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(let
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((toks (get st :toks)) (idx (+ (get st :idx) offset)))
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(if (< idx (len toks)) (nth toks idx) (nth toks (- (len toks) 1))))))
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(define er-cur (fn (st) (er-peek st 0)))
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(define er-cur-type (fn (st) (get (er-cur st) :type)))
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(define er-cur-value (fn (st) (get (er-cur st) :value)))
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(define er-advance! (fn (st) (dict-set! st :idx (+ (get st :idx) 1))))
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(define er-at-eof? (fn (st) (= (er-cur-type st) "eof")))
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(define
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er-is?
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(fn
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(st type value)
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(and
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(= (er-cur-type st) type)
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(or (= value nil) (= (er-cur-value st) value)))))
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(define
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er-expect!
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(fn
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(st type value)
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(if
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(er-is? st type value)
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(let ((t (er-cur st))) (er-advance! st) t)
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(error
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(str
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"Erlang parse: expected "
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type
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(if value (str " '" value "'") "")
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" but got "
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(er-cur-type st)
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" '"
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(er-cur-value st)
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"' at pos "
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(get (er-cur st) :pos))))))
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