io/dir/use.fz
# This file is part of the Fuzion language implementation.
#
# The Fuzion language implementation is free software: you can redistribute it
# and/or modify it under the terms of the GNU General Public License as published
# by the Free Software Foundation, version 3 of the License.
#
# The Fuzion language implementation is distributed in the hope that it will be
# useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
# License for more details.
#
# You should have received a copy of the GNU General Public License along with The
# Fuzion language implementation. If not, see <https://www.gnu.org/licenses/>.
# -----------------------------------------------------------------------
#
# Tokiwa Software GmbH, Germany
#
# Source code of Fuzion standard library feature io.dir.use
#
# -----------------------------------------------------------------------
# this opens a directory and installs the (open T) effect to be used
# in `code()`.
#
# type parameter T is used to distinguish between several open
# directories.
#
# usage example:
# ```
# use some_type path ()->
# match (open some_type).read
# e error => e
# s String => say s
# ```
public use(T, R type, path String, code ()-> outcome R) outcome R =>
match fuzion.sys.fileio.open_dir path
fd i64 =>
# install effect `open T` and run `code`
r := open T fd path
.go code
# close file
fuzion.sys.fileio.close_dir fd
# return result
r
e error =>
e
# short hand for use when
# it is not necessary to distinguish between opens
#
# usage example:
# ```
# use path ()->
# match open.read
# e error => e
# s String => say s
# ```
public use(R type, path String, code ()-> outcome R) outcome R =>
use open_unique_type R path code
last changed: 2024-03-07