diff --git a/System/Process.hsc b/System/Process.hsc --- a/System/Process.hsc +++ b/System/Process.hsc @@ -40,7 +40,9 @@ callCommand, spawnProcess, spawnCommand, + readCreateProcess, readProcess, + readCreateProcessWithExitCode, readProcessWithExitCode, -- ** Related utilities @@ -298,7 +300,7 @@ -- /Since: 1.2.0.0/ callProcess :: FilePath -> [String] -> IO () callProcess cmd args = do - exit_code <- withCreateProcess_ "callCommand" + exit_code <- withCreateProcess_ "callProcess" (proc cmd args) { delegate_ctlc = True } $ \_ _ _ p -> waitForProcess p case exit_code of @@ -413,13 +415,28 @@ -> [String] -- ^ any arguments -> String -- ^ standard input -> IO String -- ^ stdout -readProcess cmd args input = do - let cp_opts = (proc cmd args) { +readProcess cmd args = readCreateProcess $ proc cmd args + +-- | @readCreateProcess@ works exactly like 'readProcess' except that it +-- lets you pass 'CreateProcess' giving better flexibility. +-- +-- > > readCreateProcess (shell "pwd" { cwd = "/etc/" }) "" +-- > "/etc\n" +-- +-- Note that @Handle@s provided for @std_in@ or @std_out@ via the CreateProcess +-- record will be ignored. +-- /Since: 1.2.3.0/ + +readCreateProcess + :: CreateProcess + -> String -- ^ standard input + -> IO String -- ^ stdout +readCreateProcess cp input = do + let cp_opts = cp { std_in = CreatePipe, - std_out = CreatePipe, - std_err = Inherit + std_out = CreatePipe } - (ex, output) <- withCreateProcess_ "readProcess" cp_opts $ + (ex, output) <- withCreateProcess_ "readCreateProcess" cp_opts $ \(Just inh) (Just outh) _ ph -> do -- fork off a thread to start consuming the output @@ -442,16 +459,24 @@ case ex of ExitSuccess -> return output - ExitFailure r -> processFailedException "readProcess" cmd args r + ExitFailure r -> processFailedException "readCreateProcess" cmd args r + where + cmd = case cp of + CreateProcess { cmdspec = ShellCommand sc } -> sc + CreateProcess { cmdspec = RawCommand fp _ } -> fp + args = case cp of + CreateProcess { cmdspec = ShellCommand _ } -> [] + CreateProcess { cmdspec = RawCommand _ args' } -> args' + -- | @readProcessWithExitCode@ is like @readProcess@ but with two differences: --- +-- -- * it returns the 'ExitCode' of the process, and does not throw any -- exception if the code is not 'ExitSuccess'. -- -- * it reads and returns the output from process' standard error handle, -- rather than the process inheriting the standard error handle. --- +-- -- On Unix systems, see 'waitForProcess' for the meaning of exit codes -- when the process died as the result of a signal. -- @@ -460,13 +485,27 @@ -> [String] -- ^ any arguments -> String -- ^ standard input -> IO (ExitCode,String,String) -- ^ exitcode, stdout, stderr -readProcessWithExitCode cmd args input = do - let cp_opts = (proc cmd args) { +readProcessWithExitCode cmd args = + readCreateProcessWithExitCode $ proc cmd args + +-- | @readCreateProcessWithExitCode@ works exactly like 'readProcessWithExitCode' except that it +-- lets you pass 'CreateProcess' giving better flexibility. +-- +-- Note that @Handle@s provided for @std_in@, @std_out@, or @std_err@ via the CreateProcess +-- record will be ignored. +-- +-- /Since: 1.2.3.0/ +readCreateProcessWithExitCode + :: CreateProcess + -> String -- ^ standard input + -> IO (ExitCode,String,String) -- ^ exitcode, stdout, stderr +readCreateProcessWithExitCode cp input = do + let cp_opts = cp { std_in = CreatePipe, std_out = CreatePipe, std_err = CreatePipe } - withCreateProcess_ "readProcessWithExitCode" cp_opts $ + withCreateProcess_ "readCreateProcessWithExitCode" cp_opts $ \(Just inh) (Just outh) (Just errh) ph -> do out <- hGetContents outh diff --git a/System/Process/Internals.hs b/System/Process/Internals.hs --- a/System/Process/Internals.hs +++ b/System/Process/Internals.hs @@ -463,11 +463,20 @@ runInteractiveProcess_lock :: MVar () runInteractiveProcess_lock = unsafePerformIO $ newMVar () +-- The following functions are always present in the export list. For +-- compatibility with the non-Windows code, we provide the same functions with +-- matching type signatures, but implemented as no-ops. For details, see: +-- startDelegateControlC :: IO () startDelegateControlC = return () endDelegateControlC :: ExitCode -> IO () endDelegateControlC _ = return () + +stopDelegateControlC :: IO () +stopDelegateControlC = return () + +-- End no-op functions foreign import ccall unsafe "runInteractiveProcess" c_runInteractiveProcess diff --git a/cbits/runProcess.c b/cbits/runProcess.c --- a/cbits/runProcess.c +++ b/cbits/runProcess.c @@ -200,7 +200,9 @@ } // XXX Not the pipe for (i = 3; i < max_fd; i++) { - close(i); + if (i != forkCommunicationFds[1]) { + close(i); + } } } diff --git a/changelog.md b/changelog.md --- a/changelog.md +++ b/changelog.md @@ -1,5 +1,12 @@ # Changelog for [`process` package](http://hackage.haskell.org/package/process) +## 1.2.3.0 *March 2015* + + * [Meaningful error message when exe not found on close\_fds is + True](https://ghc.haskell.org/trac/ghc/ticket/3649#comment:10) + + * New functions `readCreateProcess` and `readCreateProcessWithExitCode` + ## 1.2.2.0 *Jan 2015* * Fix delegated CTRL-C handling in `createProcess` in case of failed diff --git a/configure b/configure --- a/configure +++ b/configure @@ -1,11 +1,13 @@ #! /bin/sh # Guess values for system-dependent variables and create Makefiles. -# Generated by GNU Autoconf 2.69 for Haskell process package 1.0. +# Generated by GNU Autoconf 2.68 for Haskell process package 1.0. # # Report bugs to . # # -# Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc. +# Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, +# 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software +# Foundation, Inc. # # # This configure script is free software; the Free Software Foundation @@ -134,31 +136,6 @@ # CDPATH. (unset CDPATH) >/dev/null 2>&1 && unset CDPATH -# Use a proper internal environment variable to ensure we don't fall - # into an infinite loop, continuously re-executing ourselves. - if test x"${_as_can_reexec}" != xno && test "x$CONFIG_SHELL" != x; then - _as_can_reexec=no; export _as_can_reexec; - # We cannot yet assume a decent shell, so we have to provide a -# neutralization value for shells without unset; and this also -# works around shells that cannot unset nonexistent variables. -# Preserve -v and -x to the replacement shell. -BASH_ENV=/dev/null -ENV=/dev/null -(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV -case $- in # (((( - *v*x* | *x*v* ) as_opts=-vx ;; - *v* ) as_opts=-v ;; - *x* ) as_opts=-x ;; - * ) as_opts= ;; -esac -exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"} -# Admittedly, this is quite paranoid, since all the known shells bail -# out after a failed `exec'. -$as_echo "$0: could not re-execute with $CONFIG_SHELL" >&2 -as_fn_exit 255 - fi - # We don't want this to propagate to other subprocesses. - { _as_can_reexec=; unset _as_can_reexec;} if test "x$CONFIG_SHELL" = x; then as_bourne_compatible="if test -n \"\${ZSH_VERSION+set}\" && (emulate sh) >/dev/null 2>&1; then : emulate sh @@ -192,8 +169,7 @@ else exitcode=1; echo positional parameters were not saved. fi -test x\$exitcode = x0 || exit 1 -test -x / || exit 1" +test x\$exitcode = x0 || exit 1" as_suggested=" as_lineno_1=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_1a=\$LINENO as_lineno_2=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_2a=\$LINENO eval 'test \"x\$as_lineno_1'\$as_run'\" != \"x\$as_lineno_2'\$as_run'\" && @@ -238,25 +214,21 @@ if test "x$CONFIG_SHELL" != x; then : - export CONFIG_SHELL - # We cannot yet assume a decent shell, so we have to provide a -# neutralization value for shells without unset; and this also -# works around shells that cannot unset nonexistent variables. -# Preserve -v and -x to the replacement shell. -BASH_ENV=/dev/null -ENV=/dev/null -(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV -case $- in # (((( - *v*x* | *x*v* ) as_opts=-vx ;; - *v* ) as_opts=-v ;; - *x* ) as_opts=-x ;; - * ) as_opts= ;; -esac -exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"} -# Admittedly, this is quite paranoid, since all the known shells bail -# out after a failed `exec'. -$as_echo "$0: could not re-execute with $CONFIG_SHELL" >&2 -exit 255 + # We cannot yet assume a decent shell, so we have to provide a + # neutralization value for shells without unset; and this also + # works around shells that cannot unset nonexistent variables. + # Preserve -v and -x to the replacement shell. + BASH_ENV=/dev/null + ENV=/dev/null + (unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV + export CONFIG_SHELL + case $- in # (((( + *v*x* | *x*v* ) as_opts=-vx ;; + *v* ) as_opts=-v ;; + *x* ) as_opts=-x ;; + * ) as_opts= ;; + esac + exec "$CONFIG_SHELL" $as_opts "$as_myself" ${1+"$@"} fi if test x$as_have_required = xno; then : @@ -359,14 +331,6 @@ } # as_fn_mkdir_p - -# as_fn_executable_p FILE -# ----------------------- -# Test if FILE is an executable regular file. -as_fn_executable_p () -{ - test -f "$1" && test -x "$1" -} # as_fn_executable_p # as_fn_append VAR VALUE # ---------------------- # Append the text in VALUE to the end of the definition contained in VAR. Take @@ -488,10 +452,6 @@ chmod +x "$as_me.lineno" || { $as_echo "$as_me: error: cannot create $as_me.lineno; rerun with a POSIX shell" >&2; as_fn_exit 1; } - # If we had to re-execute with $CONFIG_SHELL, we're ensured to have - # already done that, so ensure we don't try to do so again and fall - # in an infinite loop. This has already happened in practice. - _as_can_reexec=no; export _as_can_reexec # Don't try to exec as it changes $[0], causing all sort of problems # (the dirname of $[0] is not the place where we might find the # original and so on. Autoconf is especially sensitive to this). @@ -526,16 +486,16 @@ # ... but there are two gotchas: # 1) On MSYS, both `ln -s file dir' and `ln file dir' fail. # 2) DJGPP < 2.04 has no symlinks; `ln -s' creates a wrapper executable. - # In both cases, we have to default to `cp -pR'. + # In both cases, we have to default to `cp -p'. ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe || - as_ln_s='cp -pR' + as_ln_s='cp -p' elif ln conf$$.file conf$$ 2>/dev/null; then as_ln_s=ln else - as_ln_s='cp -pR' + as_ln_s='cp -p' fi else - as_ln_s='cp -pR' + as_ln_s='cp -p' fi rm -f conf$$ conf$$.exe conf$$.dir/conf$$.file conf$$.file rmdir conf$$.dir 2>/dev/null @@ -547,8 +507,28 @@ as_mkdir_p=false fi -as_test_x='test -x' -as_executable_p=as_fn_executable_p +if test -x / >/dev/null 2>&1; then + as_test_x='test -x' +else + if ls -dL / >/dev/null 2>&1; then + as_ls_L_option=L + else + as_ls_L_option= + fi + as_test_x=' + eval sh -c '\'' + if test -d "$1"; then + test -d "$1/."; + else + case $1 in #( + -*)set "./$1";; + esac; + case `ls -ld'$as_ls_L_option' "$1" 2>/dev/null` in #(( + ???[sx]*):;;*)false;;esac;fi + '\'' sh + ' +fi +as_executable_p=$as_test_x # Sed expression to map a string onto a valid CPP name. as_tr_cpp="eval sed 'y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g'" @@ -1141,6 +1121,8 @@ if test "x$host_alias" != x; then if test "x$build_alias" = x; then cross_compiling=maybe + $as_echo "$as_me: WARNING: if you wanted to set the --build type, don't use --host. + If a cross compiler is detected then cross compile mode will be used" >&2 elif test "x$build_alias" != "x$host_alias"; then cross_compiling=yes fi @@ -1373,9 +1355,9 @@ if $ac_init_version; then cat <<\_ACEOF Haskell process package configure 1.0 -generated by GNU Autoconf 2.69 +generated by GNU Autoconf 2.68 -Copyright (C) 2012 Free Software Foundation, Inc. +Copyright (C) 2010 Free Software Foundation, Inc. This configure script is free software; the Free Software Foundation gives unlimited permission to copy, distribute and modify it. _ACEOF @@ -1706,7 +1688,7 @@ test ! -s conftest.err } && test -s conftest$ac_exeext && { test "$cross_compiling" = yes || - test -x conftest$ac_exeext + $as_test_x conftest$ac_exeext }; then : ac_retval=0 else @@ -1809,8 +1791,7 @@ main () { static int test_array [1 - 2 * !(($2) >= 0)]; -test_array [0] = 0; -return test_array [0]; +test_array [0] = 0 ; return 0; @@ -1826,8 +1807,7 @@ main () { static int test_array [1 - 2 * !(($2) <= $ac_mid)]; -test_array [0] = 0; -return test_array [0]; +test_array [0] = 0 ; return 0; @@ -1853,8 +1833,7 @@ main () { static int test_array [1 - 2 * !(($2) < 0)]; -test_array [0] = 0; -return test_array [0]; +test_array [0] = 0 ; return 0; @@ -1870,8 +1849,7 @@ main () { static int test_array [1 - 2 * !(($2) >= $ac_mid)]; -test_array [0] = 0; -return test_array [0]; +test_array [0] = 0 ; return 0; @@ -1905,8 +1883,7 @@ main () { static int test_array [1 - 2 * !(($2) <= $ac_mid)]; -test_array [0] = 0; -return test_array [0]; +test_array [0] = 0 ; return 0; @@ -1979,7 +1956,7 @@ running configure, to aid debugging if configure makes a mistake. It was created by Haskell process package $as_me 1.0, which was -generated by GNU Autoconf 2.69. Invocation command line was +generated by GNU Autoconf 2.68. Invocation command line was $ $0 $@ @@ -2361,7 +2338,7 @@ IFS=$as_save_IFS test -z "$as_dir" && as_dir=. for ac_exec_ext in '' $ac_executable_extensions; do - if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then + if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then ac_cv_prog_CC="${ac_tool_prefix}gcc" $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5 break 2 @@ -2401,7 +2378,7 @@ IFS=$as_save_IFS test -z "$as_dir" && as_dir=. for ac_exec_ext in '' $ac_executable_extensions; do - if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then + if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then ac_cv_prog_ac_ct_CC="gcc" $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5 break 2 @@ -2454,7 +2431,7 @@ IFS=$as_save_IFS test -z "$as_dir" && as_dir=. for ac_exec_ext in '' $ac_executable_extensions; do - if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then + if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then ac_cv_prog_CC="${ac_tool_prefix}cc" $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5 break 2 @@ -2495,7 +2472,7 @@ IFS=$as_save_IFS test -z "$as_dir" && as_dir=. for ac_exec_ext in '' $ac_executable_extensions; do - if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then + if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then if test "$as_dir/$ac_word$ac_exec_ext" = "/usr/ucb/cc"; then ac_prog_rejected=yes continue @@ -2553,7 +2530,7 @@ IFS=$as_save_IFS test -z "$as_dir" && as_dir=. for ac_exec_ext in '' $ac_executable_extensions; do - if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then + if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then ac_cv_prog_CC="$ac_tool_prefix$ac_prog" $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5 break 2 @@ -2597,7 +2574,7 @@ IFS=$as_save_IFS test -z "$as_dir" && as_dir=. for ac_exec_ext in '' $ac_executable_extensions; do - if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then + if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then ac_cv_prog_ac_ct_CC="$ac_prog" $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5 break 2 @@ -3043,7 +3020,8 @@ /* end confdefs.h. */ #include #include -struct stat; +#include +#include /* Most of the following tests are stolen from RCS 5.7's src/conf.sh. */ struct buf { int x; }; FILE * (*rcsopen) (struct buf *, struct stat *, int); @@ -3284,7 +3262,7 @@ for ac_prog in grep ggrep; do for ac_exec_ext in '' $ac_executable_extensions; do ac_path_GREP="$as_dir/$ac_prog$ac_exec_ext" - as_fn_executable_p "$ac_path_GREP" || continue + { test -f "$ac_path_GREP" && $as_test_x "$ac_path_GREP"; } || continue # Check for GNU ac_path_GREP and select it if it is found. # Check for GNU $ac_path_GREP case `"$ac_path_GREP" --version 2>&1` in @@ -3350,7 +3328,7 @@ for ac_prog in egrep; do for ac_exec_ext in '' $ac_executable_extensions; do ac_path_EGREP="$as_dir/$ac_prog$ac_exec_ext" - as_fn_executable_p "$ac_path_EGREP" || continue + { test -f "$ac_path_EGREP" && $as_test_x "$ac_path_EGREP"; } || continue # Check for GNU ac_path_EGREP and select it if it is found. # Check for GNU $ac_path_EGREP case `"$ac_path_EGREP" --version 2>&1` in @@ -4214,16 +4192,16 @@ # ... but there are two gotchas: # 1) On MSYS, both `ln -s file dir' and `ln file dir' fail. # 2) DJGPP < 2.04 has no symlinks; `ln -s' creates a wrapper executable. - # In both cases, we have to default to `cp -pR'. + # In both cases, we have to default to `cp -p'. ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe || - as_ln_s='cp -pR' + as_ln_s='cp -p' elif ln conf$$.file conf$$ 2>/dev/null; then as_ln_s=ln else - as_ln_s='cp -pR' + as_ln_s='cp -p' fi else - as_ln_s='cp -pR' + as_ln_s='cp -p' fi rm -f conf$$ conf$$.exe conf$$.dir/conf$$.file conf$$.file rmdir conf$$.dir 2>/dev/null @@ -4283,16 +4261,28 @@ as_mkdir_p=false fi - -# as_fn_executable_p FILE -# ----------------------- -# Test if FILE is an executable regular file. -as_fn_executable_p () -{ - test -f "$1" && test -x "$1" -} # as_fn_executable_p -as_test_x='test -x' -as_executable_p=as_fn_executable_p +if test -x / >/dev/null 2>&1; then + as_test_x='test -x' +else + if ls -dL / >/dev/null 2>&1; then + as_ls_L_option=L + else + as_ls_L_option= + fi + as_test_x=' + eval sh -c '\'' + if test -d "$1"; then + test -d "$1/."; + else + case $1 in #( + -*)set "./$1";; + esac; + case `ls -ld'$as_ls_L_option' "$1" 2>/dev/null` in #(( + ???[sx]*):;;*)false;;esac;fi + '\'' sh + ' +fi +as_executable_p=$as_test_x # Sed expression to map a string onto a valid CPP name. as_tr_cpp="eval sed 'y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g'" @@ -4314,7 +4304,7 @@ # values after options handling. ac_log=" This file was extended by Haskell process package $as_me 1.0, which was -generated by GNU Autoconf 2.69. Invocation command line was +generated by GNU Autoconf 2.68. Invocation command line was CONFIG_FILES = $CONFIG_FILES CONFIG_HEADERS = $CONFIG_HEADERS @@ -4367,10 +4357,10 @@ ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`" ac_cs_version="\\ Haskell process package config.status 1.0 -configured by $0, generated by GNU Autoconf 2.69, +configured by $0, generated by GNU Autoconf 2.68, with options \\"\$ac_cs_config\\" -Copyright (C) 2012 Free Software Foundation, Inc. +Copyright (C) 2010 Free Software Foundation, Inc. This config.status script is free software; the Free Software Foundation gives unlimited permission to copy, distribute and modify it." @@ -4450,7 +4440,7 @@ _ACEOF cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1 if \$ac_cs_recheck; then - set X $SHELL '$0' $ac_configure_args \$ac_configure_extra_args --no-create --no-recursion + set X '$SHELL' '$0' $ac_configure_args \$ac_configure_extra_args --no-create --no-recursion shift \$as_echo "running CONFIG_SHELL=$SHELL \$*" >&6 CONFIG_SHELL='$SHELL' diff --git a/process.cabal b/process.cabal --- a/process.cabal +++ b/process.cabal @@ -1,5 +1,5 @@ name: process -version: 1.2.2.0 +version: 1.2.3.0 -- NOTE: Don't forget to update ./changelog.md license: BSD3 license-file: LICENSE @@ -61,10 +61,18 @@ build-depends: base >= 4.4 && < 4.9, directory >= 1.1 && < 1.3, - filepath >= 1.2 && < 1.4, + filepath >= 1.2 && < 1.5, deepseq >= 1.1 && < 1.5 if os(windows) build-depends: Win32 >=2.2 && < 2.4 extra-libraries: kernel32 else build-depends: unix >= 2.5 && < 2.8 + +test-suite test + default-language: Haskell2010 + hs-source-dirs: test + main-is: main.hs + type: exitcode-stdio-1.0 + build-depends: base + , process diff --git a/test/main.hs b/test/main.hs new file mode 100644 --- /dev/null +++ b/test/main.hs @@ -0,0 +1,14 @@ +import Control.Exception +import System.IO.Error +import System.Process + +main :: IO () +main = do + res <- handle (return . Left . isDoesNotExistError) $ do + (_, _, _, ph) <- createProcess (proc "definitelydoesnotexist" []) + { close_fds = True + } + fmap Right $ waitForProcess ph + case res of + Left True -> return () + _ -> error $ show res