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as: scan: change ungetc/2 to crash on error, remove error check from callers

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This commit is contained in:
Mikael Pettersson
2019-12-28 19:24:16 +01:00
parent ac426a91f8
commit 9ff138e590
1 changed files with 12 additions and 20 deletions
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32
erlang/apps/as/src/scan.erl
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@@ -101,7 +101,7 @@ do_fopen(Filename, IoDev) ->
put(Handle, ScanState),
{ok, Handle}.
-spec ungetc(byte(), scan_state()) -> ok | {error, {module(), term()}}.
-spec ungetc(byte(), scan_state()) -> ok.
ungetc(Ch, Handle) ->
ScanState = #scan_state{} = get(Handle),
case ScanState#scan_state.ungetc of
@@ -109,7 +109,8 @@ ungetc(Ch, Handle) ->
put(Handle, ScanState#scan_state{ungetc = Ch}),
ok;
_ ->
{error, {?MODULE, ungetc}}
%% deliberately crash on internal logic error
error({?MODULE, ungetc})
end.
-spec location(scan_state()) -> {ok, location()}.
@@ -233,11 +234,9 @@ do_octal_escape(ScanState, Val, N) ->
{ok, Ch} ->
if $0 =< Ch, Ch =< $t -> do_octal_escape(ScanState, Val * 8 + (Ch - $0), N - 1);
true ->
case ungetc(Ch, ScanState) of
{error, _Reason} = Error -> Error;
ok -> {ok, Val}
end
end
ungetc(Ch, ScanState),
{ok, Val}
end
end.
do_symbol(ScanState, Location, Chars) ->
@@ -252,10 +251,8 @@ do_symbol(ScanState, Location, Chars) ->
Ch =:= $$ orelse
Ch =:= $_ -> do_symbol(ScanState, Location, [Ch | Chars]);
true ->
case ungetc(Ch, ScanState) of
{error, _Reason} = Error -> Error;
ok -> do_symbol(Location, lists:reverse(Chars))
end
ungetc(Ch, ScanState),
do_symbol(Location, lists:reverse(Chars))
end
end.
@@ -286,10 +283,8 @@ do_number(ScanState, Location, Dig0) ->
end
end;
true ->
case ungetc(Ch, ScanState) of
{error, _Reason} = Error -> Error;
ok -> do_number(ScanState, Location, _Base = 8, _Val = 0)
end
ungetc(Ch, ScanState),
do_number(ScanState, Location, _Base = 8, _Val = 0)
end
end;
_ -> do_number(ScanState, Location, _Base = 10, _Val = Dig0 - $0)
@@ -306,10 +301,8 @@ do_number(ScanState, Location, Base, Val) ->
_ChVal when Base =< 10 andalso (Ch =:= $b orelse Ch =:= $f) ->
{ok, {Location, {?T_LOCAL_LABEL, Val, Ch}}};
_ChVal ->
case ungetc(Ch, ScanState) of
{error, _Reason} = Error -> Error;
ok -> {ok, {Location, {?T_UINTEGER, Val}}}
end
ungetc(Ch, ScanState),
{ok, {Location, {?T_UINTEGER, Val}}}
end
end.
@@ -325,7 +318,6 @@ badchar(ScanState, Ch, Context) ->
{error, {?MODULE, {FileName, LineNr, Ch, Context}}}.
-spec format_error(term()) -> io_lib:chars().
format_error(ungetc) -> "internal error: invalid ungetc";
format_error({FileName, LineNr, Ch, Context}) ->
io_lib:format("~s line ~p: invalid character '~s' ~s",
[FileName, LineNr, char_to_string(Ch), Context]).