Update documentation

You can disable this in the bindings file using: search / none

Closes #6

.clang-format

@@ -0,0 +1,14 @@
+BasedOnStyle: LLVM
+ColumnLimit: 80
+IndentWidth: 4
+TabWidth: 4
+UseTab: ForContinuationAndIndentation
+SpaceAfterCStyleCast: true
+SpaceBeforeParens: Always
+AlignAfterOpenBracket: DontAlign
+AlignEscapedNewlines: DontAlign
+AlignOperands: DontAlign
+AlignConsecutiveMacros: Consecutive
+BreakBeforeTernaryOperators: true
+SpacesBeforeTrailingComments: 2
+WhitespaceSensitiveMacros: ['XX', 'ACTIONS', 'LS']

CMakeLists.txt

@@ -1,46 +1,55 @@
 # target_compile_features has been introduced in that version
-cmake_minimum_required (VERSION 3.1.0)
-
-project (sdn CXX)
-set (version 0.1)
+cmake_minimum_required (VERSION 3.1...3.27)
+project (sdn VERSION 1.0 LANGUAGES CXX)
 
 if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU")
-	set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -pedantic")
-endif ()
-
-# Since we use a language with slow compilers, let's at least use a fast linker
-execute_process (COMMAND ${CMAKE_CXX_COMPILER} -fuse-ld=gold -Wl,--version
-	ERROR_QUIET OUTPUT_VARIABLE ld_version)
-if ("${ld_version}" MATCHES "GNU gold")
-	set (CMAKE_EXE_LINKER_FLAGS "-fuse-ld=gold ${CMAKE_EXE_LINKER_FLAGS}")
+	set (CMAKE_CXX_FLAGS
+		"${CMAKE_CXX_FLAGS} -Wall -Wextra -Wno-misleading-indentation -pedantic")
 endif ()
 
 find_package (PkgConfig REQUIRED)
-pkg_check_modules (NCURSESW QUIET ncursesw)
+pkg_check_modules (ACL libacl)
+pkg_check_modules (NCURSESW ncursesw)
+if (NOT NCURSESW_FOUND)
+	find_library (NCURSESW_LIBRARIES NAMES ncursesw)
+	find_path (NCURSESW_INCLUDE_DIRS ncurses.h PATH_SUFFIXES ncurses)
+endif ()
 
 add_executable (${PROJECT_NAME} ${PROJECT_NAME}.cpp)
-target_include_directories (${PROJECT_NAME} PUBLIC ${NCURSESW_INCLUDE_DIRS})
-target_link_libraries (${PROJECT_NAME} PUBLIC ${NCURSESW_LIBRARIES} acl)
+target_include_directories (${PROJECT_NAME}
+	PUBLIC ${NCURSESW_INCLUDE_DIRS} ${ACL_INCLUDE_DIRS})
+target_link_directories (${PROJECT_NAME}
+	PUBLIC ${NCURSESW_LIBRARY_DIRS} ${ACL_LIBRARY_DIRS})
+target_link_libraries (${PROJECT_NAME}
+	PUBLIC ${NCURSESW_LIBRARIES} ${ACL_LIBRARIES})
 target_compile_features (${PROJECT_NAME} PUBLIC cxx_std_14)
 target_compile_definitions (${PROJECT_NAME} PUBLIC
-	-DPROJECT_NAME=\"${PROJECT_NAME}\" -DPROJECT_VERSION=\"${version}\")
+	-DPROJECT_NAME=\"${PROJECT_NAME}\" -DPROJECT_VERSION=\"${PROJECT_VERSION}\")
+
+add_executable (${PROJECT_NAME}-mc-ext ${PROJECT_NAME}-mc-ext.cpp)
+target_compile_features (${PROJECT_NAME}-mc-ext PUBLIC cxx_std_17)
 
 include (GNUInstallDirs)
-install (TARGETS ${PROJECT_NAME} DESTINATION ${CMAKE_INSTALL_BINDIR})
+# sdn-mc-ext should be in libexec, but we prefer it in PATH.
+install (TARGETS sdn sdn-mc-ext
+	DESTINATION ${CMAKE_INSTALL_BINDIR})
+install (PROGRAMS sdn-install sdn-view
+	DESTINATION ${CMAKE_INSTALL_BINDIR})
+install (FILES sdn.1 sdn-install.1 sdn-view.1
+	DESTINATION ${CMAKE_INSTALL_MANDIR}/man1)
 install (FILES LICENSE DESTINATION ${CMAKE_INSTALL_DOCDIR})
 
 set (CPACK_PACKAGE_DESCRIPTION_SUMMARY "Directory navigator")
-set (CPACK_PACKAGE_VENDOR "Premysl Janouch")
-set (CPACK_PACKAGE_CONTACT "Přemysl Janouch <p@janouch.name>")
+set (CPACK_PACKAGE_VENDOR "Premysl Eric Janouch")
+set (CPACK_PACKAGE_CONTACT "Přemysl Eric Janouch <p@janouch.name>")
 set (CPACK_RESOURCE_FILE_LICENSE "${PROJECT_SOURCE_DIR}/LICENSE")
-set (CPACK_PACKAGE_VERSION ${version})
 set (CPACK_GENERATOR "TGZ;ZIP")
 set (CPACK_PACKAGE_FILE_NAME
-	"${PROJECT_NAME}-${version}-${CMAKE_SYSTEM_NAME}-${CMAKE_SYSTEM_PROCESSOR}")
-set (CPACK_PACKAGE_INSTALL_DIRECTORY "${PROJECT_NAME}-${version}")
+	"${PROJECT_NAME}-${PROJECT_VERSION}-${CMAKE_SYSTEM_NAME}-${CMAKE_SYSTEM_PROCESSOR}")
+set (CPACK_PACKAGE_INSTALL_DIRECTORY "${PROJECT_NAME}-${PROJECT_VERSION}")
 set (CPACK_SOURCE_GENERATOR "TGZ;ZIP")
 set (CPACK_SOURCE_IGNORE_FILES "/\\\\.git;/build;/CMakeLists.txt.user")
-set (CPACK_SOURCE_PACKAGE_FILE_NAME "${PROJECT_NAME}-${version}")
+set (CPACK_SOURCE_PACKAGE_FILE_NAME "${PROJECT_NAME}-${PROJECT_VERSION}")
 
 set (CPACK_SET_DESTDIR TRUE)
 include (CPack)

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2017 - 2018, Přemysl Janouch <p@janouch.name>
+Copyright (c) 2017 - 2024, Přemysl Eric Janouch <p@janouch.name>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted.

Makefile

@@ -1,12 +1,19 @@
+.POSIX:
 SHELL = /bin/sh
-CXXFLAGS = -g -std=c++14 -Wall -Wextra -pedantic -static-libstdc++
+CXXFLAGS = -g -std=c++14 -Wall -Wextra -Wno-misleading-indentation -pedantic
+CPPFLAGS = `sed -ne '/^project (\([^ )]*\) VERSION \([^ )]*\).*/ \
+	s//-DPROJECT_NAME="\1" -DPROJECT_VERSION="\2"/p' CMakeLists.txt`
 
-all: sdn
-%: %.cpp CMakeLists.txt
-	$(CXX) $(CXXFLAGS) $< -o $@ `pkg-config --libs --cflags ncursesw` -lacl \
-	`sed -ne 's/^project (\([^ )]*\).*/-DPROJECT_NAME="\1"/p' \
-	-e 's/^set (version \([^ )]*\).*/-DPROJECT_VERSION="\1"/p' CMakeLists.txt`
+sdn: sdn.cpp CMakeLists.txt
+	$(CXX) $(CXXFLAGS) $(CPPFLAGS) $< -o $@ \
+	-lacl `pkg-config --libs --cflags ncursesw`
+sdn-static: sdn.cpp CMakeLists.txt
+	$(CXX) $(CXXFLAGS) $(CPPFLAGS) $< -o $@ \
+	-static-libstdc++ \
+	-Wl,--start-group,-Bstatic \
+	-lacl `pkg-config --static --libs --cflags ncursesw` \
+	-Wl,--end-group,-Bdynamic
 clean:
-	rm -f sdn
+	rm -f sdn sdn-static
 
-.PHONY: all clean
+.PHONY: clean

NEWS

@@ -0,0 +1,20 @@
+Unreleased
+
+ * Added selection functionality, and adjusted key bindings:
+    - C-t or Insert toggle whether the current item is selected;
+    - + and - adjust the selection using shell globs;
+    - t and T insert the selection into the external command line
+      in relative or absolute form, respectively;
+	- Enter is like t but enters directories, and M-Enter is synonymous to t;
+    - C-g or Escape clear the selection, similarly to the editor.
+
+ * Added an sdn-view script that can process Midnight Commander mc.ext.ini files
+   and apply matching filters; this script has been made the default F3 binding,
+   while the original direct pager invocation has been moved to F13 (which also
+   reflects Midnight Commander)
+
+
+1.0.0 (2024-12-21)
+
+ * Initial release
+

README.adoc

@@ -5,21 +5,35 @@ sdn
 'sdn' is a simple directory navigator that you can invoke while editing shell
 commands.  It enables you to:
 
- * take a quick peek at directory contents without running `ls`
+ * take a quick peek at directory contents without running `ls`;
+ * select files to insert into the command line;
  * browse the filesystem without all the mess that Midnight Commander does:
    there's no need to create a subshell in a new pty.  The current command line
    can be simply forwarded if it is to be edited.  What's more, it will always
    be obvious whether the navigator is running.
 
-Development has just started and the only supported platform is Linux.
-I wanted to try a different, simpler approach here.
+'sdn' runs on Linux and all BSD derivatives.  I wanted to try a different,
+simpler approach here, and the end result is very friendly to tinkering.
+
+image::sdn.png[align="center"]
+
+Packages
+--------
+Regular releases are sporadic.  git master should be stable enough.
+You can get a package with the latest development version using Arch Linux's
+https://aur.archlinux.org/packages/sdn-git[AUR],
+or as a https://git.janouch.name/p/nixexprs[Nix derivation].
 
 Building
 --------
-Build dependencies: CMake and/or make, a C++14 compiler, pkg-config +
-Runtime dependencies: ncursesw
+Build dependencies: CMake and/or make, a C++17 compiler, pkg-config +
+Runtime dependencies: ncursesw, libacl (on Linux)
 
- $ git clone https://github.com/pjanouch/sdn.git
+// Working around libasciidoc's missing support for escaping it like \++
+Unfortunately most LLVM libc{plus}{plus} versions have a bug that crashes 'sdn'
+on start.  Use GNU libstdc{plus}{plus} if you're affected.
+
+ $ git clone https://git.janouch.name/p/sdn.git
  $ mkdir sdn/build
  $ cd sdn/build
  $ cmake .. -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Debug
@@ -37,64 +51,68 @@ Or you can try telling CMake to make a package for you.  For Debian it is:
 There is also a Makefile you can use to quickly build a binary to be copied
 into the PATH of any machine you want to have 'sdn' on.
 
-zsh
----
-To start using this navigator, put the following in your .zshrc:
-....
-sdn-navigate () {
-  # ... possibly zle-line-init
-  eval `sdn`
-  [ -z "$cd" ] || cd "$cd"
-  [ -z "$insert" ] || LBUFFER="$LBUFFER$insert "
-  zle reset-prompt
-  # ... possibly zle-line-finish
-}
-zle -N sdn-navigate
-bindkey '\eo' sdn-navigate
-....
+Configuration
+-------------
+For a slightly more technical explanation please refer to manual pages.
 
-bash
-----
-Here we can't reset the prompt from within a `bind -x` handler but there is
-an acceptable workaround:
-....
-sdn-navigate () {
-  SDN_L=$READLINE_LINE SDN_P=$READLINE_POINT
-  READLINE_LINE=
+Integration
+~~~~~~~~~~~
+The package contains an installation script called 'sdn-install' which will bind
+'sdn' to Alt-o in your shell's initialisation file.  The supported shells are:
 
-  eval `sdn`
-  [[ -z "$cd" ]] || cd "$cd"
-  [[ -z "$insert" ]] || {
-    SDN_L="${SDN_L:0:$SDN_P}$insert ${SDN_L:$SDN_P}"
-    ((SDN_P=SDN_P+${#insert}+1))
-  }
-}
-sdn-restore () {
-  READLINE_LINE=$SDN_L READLINE_POINT=$SDN_P
-  unset SDN_L SDN_P
-}
+ - *zsh*: works well
+ - *bash*: minor issue: exiting the navigator confirms an empty prompt
+ - *fish*: works well
+ - *elvish*: version 0.14.1 and above, an unstable API is used, works well
++
+elvish is absolutely perverse.  And so is integrating 'sdn' into it because it
+already includes a custom file manager, bound to Ctrl-N (though I find the
+ranger-like interface confusing and resource-demanding).
 
-bind -x '"\200": sdn-navigate'
-bind -x '"\201": sdn-restore'
-bind '"\eo":"\200\C-m\201"'
-....
-
-Colors
-------
+Colours
+~~~~~~~
 Here is an example of a '~/.config/sdn/look' file; the format is similar to
-that of git, only named colors aren't supported:
+that of git, only named colours aren't supported:
+
 ....
 cursor 231 202
+select 202 bold
 bar 16 255 ul
 cwd bold
 input
+cmdline 145
 ....
 
-Similar software
-----------------
- * https://elvish.io/ is an entire shell with an integrated ranger-like file
-   manager on Ctrl-N (I find this confusing and resource-demanding, preferring
-   to keep closer to "orthodox file managers")
+Filename colours are taken from the `LS_COLORS` environment variable.
+Run `dircolors` to get some defaults.
+
+Bindings
+~~~~~~~~
+To obtain more vifm-like controls, you may write the following to your
+'~/.config/sdn/bindings' file:
+
+....
+normal h parent
+normal l enter
+....
+
+Helper programs
+~~~~~~~~~~~~~~~
+The F3, F13 and F4 keys are normally bound to actions 'view', 'view-raw',
+and 'edit', similarly to Norton Commander and other orthodox file managers.
+The helper programs used here may be changed by setting the PAGER and VISUAL
+(or EDITOR) environment variables.
+
+If 'view' finds Midnight Commander, it will make use of its configuration
+to apply any matching filter, such as to produce archive listings,
+or it will run the respective command.
+
+While it is mostly possible to get 'mcview' working using an invocation like
+`PAGER='mcview -u' sdn`, beware that this helper cannot read files from its
+standard input, nor does it enable overstrike processing by default (F9, could
+be hacked around in 'mc.ext' by turning on the `nroff` switch for a custom file
+extension, just without actually invoking 'nroff'), and thus it can't show the
+program help.  'sdn' is currently optimised for 'less' as the pager.
 
 Contributing and Support
 ------------------------

sdn-install

@@ -0,0 +1,182 @@
+#!/bin/sh -e
+# sdn-install: integrate sdn with the shell, binding to M-o
+# vim: set sw=2 ts=2 sts=2 et tw=80:
+
+zsh() {
+cat <<'EOF'
+sdn-navigate () {
+  # optionally: zle zle-line-finish
+  while eval "`SDN=1 sdn "$BUFFER" "$CURSOR"`"
+  do
+    [ -z "$cd" ] || cd "$cd"
+    [ -z "$insert" ] || LBUFFER="$LBUFFER$insert "
+    [ -z "$helper" ] && break
+
+    # Workaround for "zsh: suspended (tty output)" when invoking
+    # helpers after the terminal has been resized while running sdn
+    command true
+
+    # Add to history, see https://www.zsh.org/mla/workers/2020/msg00633.html
+    fc -R =(print -- "$helper")
+
+    /bin/sh -c "$helper" </dev/tty || break
+  done
+  # optionally: zle zle-line-init
+  zle reset-prompt
+}
+
+zle -N sdn-navigate
+bindkey '\eo' sdn-navigate
+EOF
+}
+
+bash() {
+cat <<'EOF'
+# We can't make the shell update the prompt on directory changes
+# since there's no way to invoke `prompt_again()` from a `bind -x`
+# handler but we can work around it by submitting a blank line.
+sdn-cursor () {
+  if [[ $BASH_VERSINFO -lt 5 ]]
+  then echo -n "$SDN_L" | wc -m
+  else echo "$SDN_P"
+  fi
+}
+
+sdn-navigate () {
+  SDN_L=$READLINE_LINE SDN_P=$READLINE_POINT
+  READLINE_LINE=
+
+  while eval "`SDN=1 sdn "$SDN_L" "$(sdn-cursor)"`"
+  do
+    [[ -z $cd ]] || cd "$cd"
+    [[ -z $insert ]] || {
+      SDN_L="${SDN_L:0:$SDN_P}$insert ${SDN_L:$SDN_P}"
+      ((SDN_P=SDN_P+${#insert}+1))
+    }
+    [[ -z $helper ]] && break
+    history -s -- "$helper"
+    /bin/sh -c "$helper" || break
+  done
+}
+
+sdn-restore () {
+  READLINE_LINE=$SDN_L READLINE_POINT=$SDN_P
+  unset SDN_L SDN_P
+}
+
+# These never occur in UTF-8: \300-\301 \365-\367 \370-\377
+bind -x '"\300": sdn-navigate'
+bind -x '"\301": sdn-restore'
+bind '"\eo": "\300\C-m\301"'
+EOF
+}
+
+fish() {
+cat <<'EOF'
+function sdn-navigate
+  set --local IFS
+  set --local buffer (commandline)
+  set --local cursor (commandline --cursor)
+  while eval (SDN=1 sdn $buffer $cursor | \
+    string replace -ar '^(.*?)=' 'set --$1 ')
+    test -z "$cd" || cd "$cd"
+    test -z "$insert" || commandline --insert "$insert "
+    test -z "$helper" && break
+    /bin/sh -c "$helper" || break
+  end
+  commandline --function repaint
+end
+bind \eo sdn-navigate
+EOF
+}
+
+elvish() {
+cat <<'EOF'
+edit:insert:binding[Alt-o] = {
+  use str
+  local:reesc = [posix]{ str:replace "'\\''"  "''" $posix }
+  local:posix = [cmd]{ /bin/sh -c $cmd </dev/tty >/dev/tty 2>&1 }
+
+  # XXX: the -dot is not a stable API, and may hence break soon
+  # https://elv.sh/ref/builtin.html#do-not-use-functions-and-variables
+  local:buffer = $edit:current-command
+  local:cursor = (str:to-codepoints $buffer[0..$edit:-dot] | count)
+  local:ns = (ns [&])
+  while ?(eval ($reesc (E:SDN=1 sdn $buffer $cursor |
+    sed 's/^local //' | slurp)) &ns=$ns) {
+    if (not-eq $ns[cd] "") { cd $ns[cd] }
+    if (not-eq $ns[insert] "") { edit:insert-at-dot $ns[insert]" " }
+    if (or (eq $ns[helper] "") (not ?($posix $ns[helper]))) { break }
+  }
+  edit:redraw &full=$true
+}
+EOF
+}
+
+shell= path=
+while getopts s:f:h opt
+do
+  case $opt in
+  s) shell=$OPTARG;;
+  f) path=$OPTARG;;
+  *) echo "Usage: $0 [-s SHELL] [-f RCPATH | -]"; exit 2
+  esac
+done
+
+# Figure out the shell to integrate with
+login=$(basename "$SHELL")
+actual=$(ps -p $$ -o ppid= | xargs ps -o comm= -p | sed 's/^-//')
+if [ -z "$shell" ]
+then
+  if [ "$login" != "$actual" ]
+  then
+    echo "Conflict between login ($login) and invoking ($actual) shell."
+    echo "Specify the shell with the -s option."
+    exit 1
+  fi
+  shell=$actual
+fi
+
+# Figure out the default initialisation file
+case "$shell" in
+zsh|bash)
+  rc=~/.${shell}rc;;
+fish)
+  rc=${XDG_CONFIG_HOME:-$HOME/.config}/fish/conf.d/sdn.fish;;
+elvish)
+  rc=~/.elvish/rc.elv;;
+*)
+  echo "$shell is not supported."
+  exit 1
+esac
+
+# Just print out the snippet if requested
+if [ "$path" = "-" ]
+then
+  $shell
+  exit 0
+fi
+
+# Finally append to or update the appropriate file
+b="# sdn-install begin"
+e="# sdn-install end"
+[ -z "$path" ] && path=$rc
+mkdir -p "$(dirname "$path")"
+touch "$path"
+
+if ! grep -q "^$b" "$path" 2>/dev/null || ! grep -q "^$e" "$path" 2>/dev/null
+then
+  printf "\n$b\n%s\n$e\n" "$($shell)" >> "$path"
+  echo "The snippet has been added to $path"
+  exit 0
+fi
+
+# POSIX-compliant in-place sed, trying to retain permissions here
+temp=$path.sdn.new
+cp -p -- "$path" "$temp"
+sed < "$path" > "$temp" "/^$b/,/^$e/c\\
+$b\\
+$($shell | sed 's/\\/&&/g; s/$/\\/')
+$e"
+mv -- "$temp" "$path"
+echo "The snippet in $path has been updated."

sdn-install.1

@@ -0,0 +1,35 @@
+.Dd October 27, 2020
+.Dt SDN-INSTALL 1
+.Os
+.Sh NAME
+.Nm sdn-install
+.Nd integrate sdn with the shell
+.Sh SYNOPSIS
+.Nm sdn-install
+.Op Fl s Ar shell
+.Op Fl p Ar - | rcpath
+.Sh DESCRIPTION
+.Nm
+integrates
+.Xr sdn 1
+with your shell, binding it to M-o.  If the navigator has already been
+integrated, it updates the snippet in-place.
+.Pp
+The options are as follows:
+.Bl -tag -width Ds
+.It Fl p Ar -
+Merely print the integration snippet for the appropriate shell to the standard
+output, not changing anything.
+.It Fl p Ar rcpath
+Install the integration snippet into a different shell initialization file than
+the default one for your user.
+.It Fl s Ar shell
+If you want to integrate
+.Xr sdn 1
+with a different shell than the one you're running, use this option to specify
+it.
+.El
+.Sh REPORTING BUGS
+Use
+.Lk https://git.janouch.name/p/sdn
+to report bugs, request features, or submit pull requests.

sdn-mc-ext.cpp

@@ -0,0 +1,222 @@
+//
+// sdn-mc-ext: Midnight Commander extension file processor
+//
+// Copyright (c) 2024, Přemysl Eric Janouch <p@janouch.name>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+
+#include <cstdlib>
+#include <cctype>
+#include <iostream>
+#include <regex>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+// Trailing return types make C++ syntax suck considerably less
+#define fun static auto
+
+using namespace std;
+
+// It is completely fine if this only modifies ASCII letters.
+fun tolower (const string &s) -> string {
+    string result;
+	for (auto c : s) result += tolower (c);
+    return result;
+}
+
+fun shell_escape (const string &v) -> string {
+    return "'" + regex_replace (v, regex {"'"}, "'\\''") + "'";
+}
+
+string arg_type, arg_path, arg_basename, arg_dirname, arg_verb;
+unordered_map<string, unordered_map<string, string>> sections;
+
+fun expand_command (string command) -> pair<string, string> {
+	regex re_sequence {R"(%(%|[[:alpha:]]*\{([^}]*)\}|[[:alpha:]]+))"};
+	regex re_name {R"([^{}]*)"};
+	regex re_parameter {R"([^,]+")"};
+	string kind, out, pipe; smatch m;
+	while (regex_search (command, m, re_sequence)) {
+		out.append (m.prefix ());
+		auto seq = m.str (1);
+		command = m.suffix ();
+
+		string argument = m.str (2);
+		if (regex_search (seq, m, re_name))
+			seq = m.str ();
+
+		if (seq == "%") {
+			out += "%";
+		} else if (seq == "p") {
+			out += shell_escape (arg_basename);
+		} else if (seq == "f") {
+			out += shell_escape (arg_path);
+		} else if (seq == "d") {
+			out += shell_escape (arg_dirname);
+		} else if (seq == "var") {
+			string value;
+			if (auto colon = argument.find (':'); colon == argument.npos) {
+				if (auto v = getenv (argument.c_str ()))
+					value = v;
+			} else {
+				value = argument.substr (colon + 1);
+				if (auto v = getenv (argument.substr (0, colon).c_str ()))
+					value = v;
+			}
+			out += shell_escape (value);
+		} else if (seq == "cd") {
+			kind = seq;
+			command = regex_replace (command, regex {"^ +"}, "");
+		} else if (seq == "view") {
+			kind = seq;
+			command = regex_replace (command, regex {"^ +"}, "");
+
+			sregex_token_iterator it (argument.begin (), argument.end (),
+				re_parameter, 0), end;
+			for (; it != end; it++) {
+				if (*it == "hex")
+					pipe.append (" | od -t x1");
+
+				// more(1) and less(1) either ignore or display this:
+				//if (*it == "nroff")
+				//	pipe.append (" | col -b");
+			}
+		} else if (seq == "") {
+			cerr << "sdn-mc-ext: prompting not supported" << endl;
+			return {};
+		} else {
+			cerr << "sdn-mc-ext: unsupported: %" << seq << endl;
+			return {};
+		}
+	}
+	return {kind,
+		pipe.empty () ? out.append (command) : "(" + out + ")" + pipe};
+}
+
+fun print_command (string cmd) {
+	auto command = expand_command (cmd);
+	cout << get<0> (command) << endl << get<1> (command) << endl;
+}
+
+fun section_matches (const unordered_map<string, string> &section) -> bool {
+	if (section.count ("Directory"))
+		return false;
+
+	// The configuration went through some funky changes;
+	// unescape \\ but leave other escapes alone.
+	auto filter_re = [](const string &s) {
+		string result;
+		for (size_t i = 0; i < s.length (); ) {
+			auto c = s[i++];
+			if (c == '\\' && i < s.length ())
+				if (c = s[i++]; c != '\\')
+					result += '\\';
+			result += c;
+		}
+		return result;
+	};
+	auto is_true = [&](const string &name) {
+		auto value = section.find (name);
+		return value != section.end () && value->second == "true";
+	};
+	if (auto kv = section.find ("Type"); kv != section.end ()) {
+		auto flags = std::regex::ECMAScript;
+		if (is_true ("TypeIgnoreCase"))
+			flags |= regex_constants::icase;
+		if (!regex_search (arg_type, regex {filter_re (kv->second), flags}))
+			return false;
+	}
+	auto basename = arg_basename;
+	if (auto kv = section.find ("Regex"); kv != section.end ()) {
+		auto flags = std::regex::ECMAScript;
+		if (is_true ("RegexIgnoreCase"))
+			flags |= regex_constants::icase;
+		return regex_search (basename, regex {filter_re (kv->second), flags});
+	}
+	if (auto kv = section.find ("Shell"); kv != section.end ()) {
+		auto value = kv->second;
+		if (is_true ("ShellIgnoreCase")) {
+			value = tolower (value);
+			basename = tolower (arg_basename);
+		}
+		if (value.empty () || value[0] != '.')
+			return value == basename;
+		return basename.length () >= value.length () &&
+			basename.substr (basename.length () - value.length ()) == value;
+	}
+	return !arg_type.empty ();
+}
+
+fun process (const string &section) -> bool {
+	auto full = sections.at (section);
+	if (auto include = full.find ("Include"); include != full.end ()) {
+		full.erase ("Open");
+		full.erase ("View");
+		full.erase ("Edit");
+
+		if (auto included = sections.find ("Include/" + include->second);
+			included != sections.end ()) {
+			for (const auto &kv : included->second)
+				full[kv.first] = kv.second;
+		}
+	}
+	if (getenv ("SDN_MC_EXT_DEBUG")) {
+		cerr << "[" << section << "]" << endl;
+		for (const auto &kv : full)
+			cerr << "  " << kv.first << ": " << kv.second << endl;
+	}
+	if (full.count (arg_verb) && section_matches (full)) {
+		print_command (full[arg_verb]);
+		return true;
+	}
+	return false;
+}
+
+int main (int argc, char *argv[]) {
+	if (argc != 6) {
+		cerr << "Usage: " << argv[0]
+			<< " TYPE PATH BASENAME DIRNAME VERB < mc.ext.ini" << endl;
+		return 2;
+	}
+
+	arg_type = argv[1];
+	arg_path = argv[2], arg_basename = argv[3], arg_dirname = argv[4];
+	arg_verb = argv[5];
+
+	string line, section;
+	vector<string> order;
+	regex re_entry {R"(^([-\w]+) *= *(.*)$)"};
+	smatch m;
+	while (getline (cin, line)) {
+		if (line.empty () || line[0] == '#') {
+			continue;
+		} else if (auto length = line.length();
+			line.find_last_of ('[') == 0 &&
+			line.find_first_of (']') == length - 1) {
+			order.push_back ((section = line.substr (1, length - 2)));
+		} else if (regex_match (line, m, re_entry)) {
+			sections[section][m[1]] = m[2];
+		}
+	}
+	for (const auto &section : order) {
+		if (section == "mc.ext.ini" ||
+			section == "Default" ||
+			section.substr (0, 8) == "Include/")
+			continue;
+		if (process (section))
+			return 0;
+	}
+	print_command (sections["Default"][arg_verb]);
+	return 0;
+}

sdn-view

@@ -0,0 +1,54 @@
+#!/bin/sh -e
+# sdn-view: a viewer for sdn that makes use of Midnight Commander configuration
+# to make more kinds of files directly viewable
+
+if [ "$#" -ne 1 ]
+then
+	echo "Usage: $0 FILE" >&2
+	exit 2
+fi
+
+# This handles both MC_DATADIR and odd installation locations.
+datadir=
+if command -v mc >/dev/null
+then datadir=$(mc --datadir | sed 's/ (.*)$//')
+fi
+
+config=
+for dir in "$HOME"/.config/mc "$datadir" /etc/mc
+do
+	if [ -n "$dir" -a -f "$dir/mc.ext.ini" ]
+	then
+		config=$dir/mc.ext.ini
+		break
+	fi
+done
+
+# This is often used in %env{} expansion, so let's be on the same page.
+export PAGER=${PAGER:-less}
+
+export MC_EXT_FILENAME=$(realpath "$1")
+export MC_EXT_BASENAME=$(basename "$1")
+export MC_EXT_CURRENTDIR=$(dirname "$MC_EXT_FILENAME")
+output=$(sdn-mc-ext <"$config" "$(file -Lbz "$1")" \
+	"$MC_EXT_FILENAME" "$MC_EXT_BASENAME" "$MC_EXT_CURRENTDIR" View || :)
+kind=$(echo "$output" | sed -n 1p)
+command=$(echo "$output" | sed -n 2p)
+
+case "$kind" in
+view)
+	if [ -n "$command" ]
+	then eval "$command" | "$PAGER"
+	else "$PAGER" -- "$MC_EXT_FILENAME"
+	fi
+	;;
+'')
+	if [ -n "$command" ]
+	then eval "$command"
+	else "$PAGER" -- "$MC_EXT_FILENAME"
+	fi
+	;;
+*)
+	echo "Unsupported: $kind" >&2
+	exit 1
+esac

sdn-view.1

@@ -0,0 +1,24 @@
+.Dd December 30, 2024
+.Dt SDN-VIEW 1
+.Os
+.Sh NAME
+.Nm sdn-view
+.Nd run Midnight Commander view configuration externally
+.Sh SYNOPSIS
+.Nm sdn-view
+.Ar path
+.Sh DESCRIPTION
+.Nm
+invokes
+.Ev PAGER
+or a fallback pager on the passed filename.
+.Pp
+If it succeeds in finding a
+.Xr mc 1
+.Pa mc.ext.ini
+file, it will first process it, and apply any matching filter,
+or run the respective command.
+.Sh REPORTING BUGS
+Use
+.Lk https://git.janouch.name/p/sdn
+to report bugs, request features, or submit pull requests.

sdn.1

@@ -0,0 +1,132 @@
+\" https://mandoc.bsd.lv/man/roff.7.html#Sentence_Spacing
+.Dd December 30, 2024
+.Dt SDN 1
+.Os
+.Sh NAME
+.Nm sdn
+.Nd directory navigator
+.Sh SYNOPSIS
+.Nm sdn
+.Op Ar line Ar point
+.Nm sdn
+.Cm --version
+.Sh DESCRIPTION
+.Nm
+is a simple directory navigator that you can launch while editing shell
+commands.
+Use the
+.Xr sdn-install 1
+script to integrate it with your shell, then invoke it at any time with M-o.
+.Pp
+Press F1 to get a list of active key bindings and their assigned actions,
+grouped by their contexts.
+.Pp
+Program arguments are only used by integration snippets to forward the parent
+shell's command line.
+The
+.Ar point
+is given in terms of characters.
+.Sh OPTIONS
+While some behaviour can be toggled from within the program, some can only be
+changed by modifying configuration files manually.
+.Pp
+The files follow a simple syntax derived from the Bourne shell: each option is
+on its own line, with words separated by linear whitespace.
+Comments start with a hash (#) and continue until the end of the line.
+All special characters may be quoted using either a backslash or single-quoted
+strings.
+.Pp
+The options and the default key bindings controlling them are as follows:
+.Bl -tag
+.It full-view Em bool No (t)
+If non-zero, the equivalent format to
+.Ql ls -l
+is used to display directory contents rather than simply listing the filenames.
+.It gravity Em bool
+If non-zero, all entries stick to the bottom of the screen, i.e., all empty
+space is at the top.
+.It reverse-sort Em bool No (R)
+If non-zero, the order of entries is reversed.
+.It show-hidden Em bool No (M-.)
+If non-zero, filenames beginning with a full stop are shown.
+.It ext-helpers Em bool
+If non-zero, viewers and editors are launched from the parent shell.
+This way you can suspend them and use job control features of the shell.
+However it also enforces any pending change to the shell's working directory.
+.It sort-column Em number No (< >)
+The zero-based index of the
+.Ql full-view
+column that entries are ordered by.
+.El
+.Sh ENVIRONMENT
+.Bl -tag -width 15n
+.It Ev LS_COLORS
+Used to retrieve filename colours.
+The format is described in
+.Xr dir_colors 5
+and you can use the
+.Xr dircolors 1
+utility to initialize this variable.
+.It Ev PAGER
+The viewer program to be launched by the F3 and F13 key bindings as well as
+to show the internal help message.
+If none is set, it defaults to
+.Xr less 1 .
+.It Ev VISUAL , Ev EDITOR
+The editor program to be launched by the F4 key binding.
+If neither variable is set, it defaults to
+.Xr vi 1 .
+.El
+.Sh FILES
+.Bl -tag -width 25n -compact
+.It Pa ~/.config/sdn/config
+Program configuration and navigation state, initialized or overwritten on exit.
+.It Pa ~/.config/sdn/bindings
+Custom key binding overrides.
+.It Pa ~/.config/sdn/look
+Redefine terminal attributes for UI elements.
+.El
+.Sh EXAMPLES
+.Ss Pa bindings
+Key names or combinations follow the Emacs syntax for Control and Meta prefixes
+and
+.Xr terminfo 5
+names are used for special keys.
+To obtain more vifm-like controls and Windows-like quit abilities:
+.Bd -literal -offset indent
+normal h parent
+normal l enter
+normal M-f4 quit
+.Ed
+.Pp
+Midnight Commander binds the same traversal actions to sequences normally
+unknown to ncurses, due to them being missing from terminfo.
+You'll need to define them manually to match your terminal.
+For rxvt, that would be:
+.Bd -literal -offset indent
+define C-ppage ^[[5^
+define C-npage ^[[6^
+normal C-ppage parent
+normal C-npage enter
+.Ed
+.Pp
+Escape characters must be inserted verbatim, e.g., by pressing C-v ESC in vi,
+or C-q ESC in Emacs.
+.Ss Pa look
+Terminal attributes are accepted in a format similar to that of
+.Xr git-config 1 ,
+only named colours aren't supported.
+For a black-on-white terminal supporting 256 colours, a theme such as the
+following may work:
+.Bd -literal -offset indent
+cursor 231 202
+select 202 bold
+bar 16 255 ul
+cwd bold
+input
+cmdline 145
+.Ed
+.Sh REPORTING BUGS
+Use
+.Lk https://git.janouch.name/p/sdn
+to report bugs, request features, or submit pull requests.