-module(glisp@environment).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([new/0, get/2, set/3]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC("// A module for managing environments that map variable names to expressions.\n").

-file("src/glisp/environment.gleam", 12).
?DOC(" Create a new empty environment\n").
-spec new() -> gleam@dict:dict(binary(), glisp@ast:expr()).
new() ->
    maps:new().

-file("src/glisp/environment.gleam", 17).
?DOC(" Get a value from the environment\n").
-spec get(gleam@dict:dict(binary(), glisp@ast:expr()), binary()) -> {ok,
        glisp@ast:expr()} |
    {error, binary()}.
get(Env, Key) ->
    case gleam_stdlib:map_get(Env, Key) of
        {ok, Value} ->
            {ok, Value};

        {error, _} ->
            {error, <<"Unknown variable: "/utf8, Key/binary>>}
    end.

-file("src/glisp/environment.gleam", 25).
?DOC(" Set a value in the environment\n").
-spec set(
    gleam@dict:dict(binary(), glisp@ast:expr()),
    binary(),
    glisp@ast:expr()
) -> gleam@dict:dict(binary(), glisp@ast:expr()).
set(Env, Key, Value) ->
    gleam@dict:insert(Env, Key, Value).