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033892777a
See issue #587. * Merge eval-ast and eval into a single conditional. * Expand macros during the apply phase, removing lots of duplicate tests, and increasing the overall consistency by allowing the macro to be computed instead of referenced by name (`((defmacro! cond (...)))` is currently illegal for example). * Print "EVAL: $ast" at the top of EVAL if DEBUG-EVAL exists in the MAL environment. * Remove macroexpand and quasiquoteexpand special forms. * Use pattern-matching style in process/step*.txt. Unresolved issues: c.2: unable to reproduce with gcc 11.12.0. elm: the directory is unchanged. groovy: sometimes fail, but not on each rebuild. nasm: fails some new soft tests, but the issue is unreproducible when running the interpreter manually. objpascal: unreproducible with fpc 3.2.2. ocaml: unreproducible with 4.11.1. perl6: unreproducible with rakudo 2021.09. Unrelated changes: Reduce diff betweens steps. Prevent defmacro! from mutating functions: c forth logo miniMAL vb. dart: fix recent errors and warnings ocaml: remove metadata from symbols. Improve the logo implementation. Encapsulate all representation in types.lg and env.lg, unwrap numbers. Replace some manual iterations with logo control structures. Reduce the diff between steps. Use native iteration in env_get and env_map Rewrite the reader with less temporary strings. Reduce the number of temporary lists (for example, reverse iteration with butlast requires O(n^2) allocations). It seems possible to remove a few exceptions: GC settings (Dockerfile), NO_SELF_HOSTING (IMPLS.yml) and step5_EXCLUDES (Makefile.impls) .
70 lines
2.1 KiB
Standard ML
70 lines
2.1 KiB
Standard ML
exception NotDefined of string
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exception NotApplicable of string
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fun read s =
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readStr s
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(* TextIO.print ("EVAL: " ^ prReadableStr ast ^ "\n") *)
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fun eval e ast = case ast of
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LIST (_::_,_) => evalApply e ast
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| _ => evalAst e ast
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and evalAst e ast = case ast of
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SYMBOL s => (case lookup e s of SOME v => v | NONE => raise NotDefined ("unable to resolve symbol '" ^ s ^ "'"))
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| LIST (l,_) => LIST (List.map (eval e) l, NO_META)
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| VECTOR (v,_) => VECTOR (List.map (eval e) v, NO_META)
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| MAP (m,_) => MAP (List.map (fn (k, v) => (k, eval e v)) m, NO_META)
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| _ => ast
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and evalApply e ast = case evalAst e ast of
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LIST ((FN (f,_))::args, _) => f args
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| _ => raise NotApplicable "eval_apply needs a non-empty list"
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fun print f =
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prReadableStr f
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fun rep e s =
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s |> read |> eval e |> print
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handle Nothing => ""
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| e => "ERROR: " ^ (exnMessage e)
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fun malPlus (INT a, INT b) = INT (a + b)
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| malPlus _ = raise NotApplicable "can only add integers"
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fun malTimes (INT a, INT b) = INT (a * b)
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| malTimes _ = raise NotApplicable "can only multiply integers"
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fun malMinus (INT b, INT a) = INT (a - b)
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| malMinus _ = raise NotApplicable "can only subtract integers"
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fun malDiv (INT b, INT a) = INT (a div b)
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| malDiv _ = raise NotApplicable "can only divide integers"
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val replEnv = ENV (NS (ref [
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("+", FN (foldl malPlus (INT 0), NO_META)),
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("*", FN (foldl malTimes (INT 1), NO_META)),
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("-", FN (
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fn [x] => malMinus (x, INT 0)
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| x::xs => foldr malMinus x xs
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| _ => raise NotApplicable "'-' requires at least one argument"
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, NO_META
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)),
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("/", FN (
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fn [x] => malDiv (x, INT 1)
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| x::xs => foldr malDiv x xs
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| _ => raise NotApplicable "'/' requires at least one argument"
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, NO_META
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))
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]))
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fun repl () =
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let open TextIO
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in (
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print("user> ");
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case inputLine(stdIn) of
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SOME(line) => (
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print((rep replEnv line) ^ "\n");
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repl ()
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)
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| NONE => ()
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) end
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fun main () = repl ()
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