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🍪 Lexer step + parser combinators + great error messages [nibble fork]

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chomp src chomp@pratt.erl
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src/chomp@pratt.erl

-module(chomp@pratt).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).
-export([sub_expression/2, expression/3, prefix_custom/3, prefix/3, infix_custom/3, infix/3, postfix_custom/3, postfix/3, operator_custom/1]).
-export_type([config/4, operator/4, precedence/0]).
-opaque config(IPR, IPS, IPT, IPU) :: {config,
list(fun((config(IPR, IPS, IPT, IPU)) -> chomp:parser(IPR, IPS, IPT, IPU))),
IPS,
list(operator(IPR, IPS, IPT, IPU))}.
-opaque operator(IPV, IPW, IPX, IPY) :: {operator,
fun((config(IPV, IPW, IPX, IPY)) -> {integer(),
fun((IPV) -> chomp:parser(IPV, IPW, IPX, IPY))})}.
-type precedence() :: {left, integer()} | {right, integer()}.
-spec operation(IRH, config(IRH, IRI, IRJ, IRK), integer()) -> chomp:parser(IRH, IRI, IRJ, IRK).
operation(Expr, Config, Current_precedence) ->
_pipe = erlang:element(4, Config),
_pipe@1 = gleam@list:filter_map(
_pipe,
fun(Operator) ->
{operator, Op} = Operator,
case Op(Config) of
{Precedence, Parser} when Precedence > Current_precedence ->
{ok, Parser(Expr)};
_ ->
{error, nil}
end
end
),
chomp:one_of(_pipe@1).
-spec sub_expression(config(IQV, IQW, IQX, IQY), integer()) -> chomp:parser(IQV, IQW, IQX, IQY).
sub_expression(Config, Precedence) ->
Expr = (chomp:lazy(fun() -> _pipe = erlang:element(2, Config),
_pipe@1 = gleam@list:map(_pipe, fun(P) -> P(Config) end),
_pipe@2 = chomp:one_of(_pipe@1),
chomp:or_error(_pipe@2, erlang:element(3, Config)) end)),
Go = fun(Expr@1) ->
chomp:one_of(
[begin
_pipe@3 = operation(Expr@1, Config, Precedence),
chomp:map(_pipe@3, fun(Field@0) -> {continue, Field@0} end)
end,
begin
_pipe@4 = chomp:return(Expr@1),
chomp:map(_pipe@4, fun(Field@0) -> {break, Field@0} end)
end]
)
end,
chomp:do(Expr, fun(E) -> chomp:loop(E, Go) end).
-spec expression(
list(fun((config(IPZ, IQA, IQB, IQC)) -> chomp:parser(IPZ, IQA, IQB, IQC))),
IQA,
list(operator(IPZ, IQA, IQB, IQC))
) -> chomp:parser(IPZ, IQA, IQB, IQC).
expression(First, Or_error, Then) ->
Config = {config, First, Or_error, Then},
sub_expression(Config, 0).
-spec prefix_custom(
integer(),
chomp:parser(ISK, ISL, ISM, ISN),
fun((ISS, ISK) -> ISS)
) -> fun((config(ISS, ISL, ISM, ISN)) -> chomp:parser(ISS, ISL, ISM, ISN)).
prefix_custom(Precedence, Operator, Apply) ->
fun(Config) ->
chomp:do(
Operator,
fun(Op) ->
chomp:do(
sub_expression(Config, Precedence),
fun(Subexpr) -> chomp:return(Apply(Subexpr, Op)) end
)
end
)
end.
-spec prefix(integer(), chomp:parser(any(), IRU, IRV, IRW), fun((ISB) -> ISB)) -> fun((config(ISB, IRU, IRV, IRW)) -> chomp:parser(ISB, IRU, IRV, IRW)).
prefix(Precedence, Operator, Apply) ->
prefix_custom(Precedence, Operator, fun(A, _) -> Apply(A) end).
-spec infix_custom(
precedence(),
chomp:parser(ITO, ITP, ITQ, ITR),
fun((ITW, ITW, ITO) -> ITW)
) -> operator(ITW, ITP, ITQ, ITR).
infix_custom(Precedence, Operator, Apply) ->
{Left_precedence, Right_precedence} = case Precedence of
{left, P} ->
{P, P};
{right, P@1} ->
{P@1, P@1 - 1}
end,
{operator,
fun(Config) ->
{Left_precedence,
fun(Lhs) ->
chomp:do(
Operator,
fun(Op) ->
chomp:do(
sub_expression(Config, Right_precedence),
fun(Subexpr) ->
chomp:return(Apply(Lhs, Subexpr, Op))
end
)
end
)
end}
end}.
-spec infix(
precedence(),
chomp:parser(any(), ITC, ITD, ITE),
fun((ITJ, ITJ) -> ITJ)
) -> operator(ITJ, ITC, ITD, ITE).
infix(Precedence, Operator, Apply) ->
infix_custom(Precedence, Operator, fun(A, B, _) -> Apply(A, B) end).
-spec postfix_custom(
integer(),
chomp:parser(IUO, IUP, IUQ, IUR),
fun((IUW, IUO) -> IUW)
) -> operator(IUW, IUP, IUQ, IUR).
postfix_custom(Precedence, Operator, Apply) ->
{operator,
fun(_) ->
{Precedence,
fun(Lhs) ->
chomp:do(
Operator,
fun(Op) -> chomp:return(Apply(Lhs, Op)) end
)
end}
end}.
-spec postfix(integer(), chomp:parser(any(), IUC, IUD, IUE), fun((IUJ) -> IUJ)) -> operator(IUJ, IUC, IUD, IUE).
postfix(Precedence, Operator, Apply) ->
postfix_custom(Precedence, Operator, fun(A, _) -> Apply(A) end).
-spec operator_custom(
fun((config(IVB, IVC, IVD, IVE)) -> {integer(),
fun((IVB) -> chomp:parser(IVB, IVC, IVD, IVE))})
) -> operator(IVB, IVC, IVD, IVE).
operator_custom(Build) ->
{operator, Build}.