The ycmd code completion support for nano is found in the ymcd-code-completion branch.

• The master branch contains upstreams gnu nano source code untouched.
• The ymcd-code-completion contains a modification to gnu nano that has ycmd support.

You can use the following which have been tested:

Compatible ycmd core versions:

• NA = Not Available
• Support for a particular ycmd core version is based on version availability of Python on the developer(s)' distro.
• The End of Life (EOL) column is interpreted from the last tested commit snapshot of nano-ycmd.
• For 2025, the commits supported for compatible ycmd core version has changed and is based on the version bump of CORE_VERSION. The version bump is assumed to be the final version and is based on other Python projects that bump the version variable in setup.py or __init__.py while simultaneously tagging the release on the repo. For ycmd, it is unclear and ambiguous which version is the official final release because there are no repo tags. The core version bump can be interpreted as either the final version or the beginning of the new development cycle.

You can use nano-ycmd fairly quickly with Docker. More information can be found at https://github.com/orsonteodoro/docker-gentoo-nano-ycmd

• [1] You must choose at least one cryptographic library.
• [2] The package must be built with --enable-strmax=131072 (128 KiB) or higher.
• [3] See the ycmd core versions table
• [4] It requires the LD_PRELOAD=$(clang --print-file-name=libclang_rt.scudo_standalone-<arch>.so) environment variable to use the standalone hardened allocator. arch is either i386, x86_64, arm, armhf, aarch64, mips, mipsel, mips64, mips64el, powerpc64, powerpc64le, hexagon, loongarch64, riscv64. It requires the kernel built with ASLR. Only use 64-bit arches for security-critical to decrease chances of ASLR bypass.
• [5] Any compatible linker
• [6] Any compatible compiler
• [7] Must add --with-scudo-lib=<PATH> and --with-lib-safe-paths=<PATH(S)> to configure. If Scudo is updated or recompiled, nano-ycmd must be rebuilt.

If you are using nano-ycmd for passwords or untrusted data (e.g. opening files from the web or without file extension), it is recommended to install hardened libraries.

• [1] A shared library Makefile patch is required for NXJSON.

You can look at my gentoo package overlay https://github.com/orsonteodoro/oiledmachine-overlay to see how to properly compile them or you can research them to build packages for your distribution.

The hotkeys Ctrl-` brings up the completer commands menu. The table below in the which completer commands work section lists additional hotkeys that follow.

See https://github.com/orsonteodoro/nano-ycmd/blob/ymcd-code-completion/src/global.c#L1389 .

Some of these features require the user to begin to type their code before the completere commands menu shows.

Your distribution has not packaged the xml files properly. Compile nano-ycmd in debug mode and inspect the logs (ynano.txt, jedihttp_.log, omnisharp_.log) in the /tmp folder to see which xml documentation files are required.

Just type and press Ctrl-letter when suggestions show.

Do Ctrl-X to exit the code completion suggestions list.

Completer commands add beyond code completion. It is optional but powerful features for the developer.

The features below are still in development. Some may be feature complete.

Do Alt-` to bring up the completer commands menu.

Do Ctrl-letter to execute a completer command.

Do Ctrl-space to exit the completer commands.

Some completer commands may not work or not made available for the particular language that you working with.

• (1) It triggers randomly (in a not deterministic way). It works for %d->%s format specifier, missing semicolon, identifier spelling errors. It was tested only with the C language.
• (2) It needs more test cases.
• (3) Subserver problems were encountered.
• (4) Interactive testing is performed.
• (5) The results currently shown are from an older evaluated version. Breakage may be encountered for newer versions.

ycmd allows to you use IntelliSense for C# sources using omnisharp-server/omnisharp-roslyn that the big IDE editors have. It goes beyond word completion providing documentation about method signatures and real time syntax checking (currently not supported in nano-ycmd).

• JavaScript (1)
• C# (2)
• C (3)
• C++ (3)
• CUDA
• Go
• Python
• Objective-C (3)
• Objective-C++ (3)
• Rust
• TypeScript

Working with some of these languages require additional requirements:

• (1) JavaScript support requires both .tern-project and .tern-config project files to work.
• (2) C# support requires a .sln project file to work.
• (3) C, C++, Objective-C, Objective-C++ requires either a *.pro, configure, CMakeList.txt, GNUmakefile, Makefile, or makefile to work. An optional *.ninja file may be supplied in your project and would require additional steps to handle. build.meson is supported through the YCM-Generator's develop branch.

You may forgot to have a Makefile, makefile GNUmakefile for make, *.pro for qmake, configure for autotools, CMakeLists.txt for cmake or forgot to set the YCMG_PROJECT_PATH to point to your top level project folder. nano-ycmd will pass it to bear and YCM-Generator to properly create a .ycm_extra_conf.py and compile_commands.json. The compile_commands.json is for clang compliation database system (https://clang.llvm.org/docs/JSONCompilationDatabase.html). .ycm_extra_conf.py contains headers and constants that are per project defined.

Try deleting the compile_commands.json file and .ycm_extra_conf.py in the current (working) directory. Those files should be only in the directory mentioned in the YCMG_PROJECT_PATH environmental variable passed into nano-ycmd.

You didn't set up ycmd correctly. It needs to see a sln file or maybe project.json file if json is supported in ycmd.

I don't have an update bot yet.

I don't see any plugin support in nano.

Your setup may vary depending on if your distro patched ycmd. In my case, I modified ycmd to use absolute paths. The vanilla ycmd uses relative path to the thirdparty folder.

• --with-libgcrypt

• --with-nettle

• --with-openssl

• For license compatibility reasons, do not use older than OpenSSL 3.x.

--enable-ycmd

(IMPORTANT) The python version must be the same as the compiled ycmd scripts.

YCMD_PATH="/usr/lib/python3.10/site-packages/ycmd"
PYTHON_PATH="/usr/bin/python3.10" 

RACERD_PATH="/usr/bin/racerd" 
RUST_SRC_PATH="/usr/share/rust/src" 

GODEF_PATH="/usr/bin/godef" 
GOCODE_PATH="/usr/bin/gocode" 

YCMG_PATH="/usr/bin/config_gen.py"

./autogen.sh
CFLAGS="-g" \
YCMG_PATH="/usr/bin/config_gen.py" \
YCMG_PYTHON_PATH="/usr/bin/python3" \
YCMD_PYTHON_PATH="/usr/bin/python3" \
RACERD_PATH="/usr/bin/racerd" \
RUST_SRC_PATH="/usr/share/rust/src" \
GODEF_PATH="/usr/bin/godef" \
GOCODE_PATH="/usr/bin/gocode" \
YCMD_PATH="/usr/lib/python3.10/site-packages/ycmd" \
./configure --enable-ycmd --with-openssl
make

The -g adds debugging information for developers for the gdb debugger but not needed for regular users.

• YCMG_PYTHON_PATH, YCMD_PYTHON_PATH is used in commit 61b82be3e3b18b642ef75a1eee693f890127ba77. YCMG is refers to ycm-generator.

• PYTHON_PATH is used for earlier builds.

The following environmental variables are defined by nano-ycmd are required for C family support (C/C++/ObjC/ObjC++):

• YCMG_PROJECT_PATH - This should point to the folder containing the top-level Makefile, configure, CMakeList.txt. (REQUIRED)
• YCMG_FLAGS - This adds extra parameters to config_gen.py. I recommend using make over autotools specifically -b make because more include files are exposed instead of allowing YCM-Generator autodetect. This environment variable is optional but recommended be in use in certain situations.

So to use it in combination of nano-ycmd (ynano) without Ninja, it would look like:

YCMG_FLAGS="-b make" \
YCMG_PROJECT_PATH="/var/tmp/portage/app-editors/nano-ycmd-9999.20170201/work/nano-ycmd-7611e4eb827980da1057f6768d00bd322fa1c58f" \
ynano ycmd.c

Also, if you add new libraries or files, you should delete both the .ycm_extra_conf.py and compile_commands.json so that nano-ycmd can regenerate them.

Also, if you change languages between C, C++, Objective-C, Objective-C++ because your project uses multiple languages, you should regenerate them when using them because it will produce new header include lists for that particular language. Currently no hotkey exist to delete and regenerate those files. nano-ycmd automatically skips generation to save time if they already exist.

We need the YCMG_PROJECT_PATH above plus the two required environment variables below:

• NINJA_BUILD_PATH - This should point to the folder containing your *.ninja file (REQUIRED)
• NINJA_BUILD_TARGETS - This should be the rule(s) space seperated and listed under the # Rules for compiling comment section and having the line begin with command = clang or whatever compiler you are using. (REQUIRED)

For NINJA_BUILD_TARGETS, the contents of gst-transcoder's build.ninja is presented below:

# This is the build file for project "gst-renderer"
# It is autogenerated by the Meson build system.
# Do not edit by hand.
ninja_required_version = 1.5.1
# Rules for compiling.
rule c_COMPILER
 command = clang  $ARGS '-MMD' '-MQ' $out '-MF' '$DEPFILE' -o $out -c $in
 deps = gcc
 depfile = $DEPFILE
 description = Compiling c object $out
rule c_PCH
 command = clang  $ARGS '-MMD' '-MQ' $out '-MF' '$DEPFILE' -o $out -c $in
 deps = gcc
 depfile = $DEPFILE
 description = Precompiling header $in
# Rules for linking.
rule STATIC_LINKER
 command = ar $LINK_ARGS $out $in
 description = Static linking library $out

NINJA_BUILD_TARGETS can only be c_COMPILER and/or c_PCH but not STATIC_LINKER. Also it only works if your project is using both YCMG_PROJECT_PATH and NINJA_BUILD_TARGETS for Ninja support.

In the above example, we have a Makefile and a configure. We override the YCM-Generator autodetection because the .ycm_extra_conf.py contains more headers with the Makefile preference over the autodetected configure with first come first serve priority.

For Ninja + Other build system, it should look like:

NINJA_BUILD_PATH="/var/tmp/portage/media-plugins/gst-transcoder-1.8.2-r1/work/gst-transcoder-1.8.2/mesonbuild" \
NINJA_BUILD_TARGETS="c_COMPILER" \
YCMG_PROJECT_PATH="/var/tmp/portage/media-plugins/gst-transcoder-1.8.2-r1/work/gst-transcoder-1.8.2" \
ynano gst/transcode/gst-cpu-throttling-clock.c 2>out.txt

In the above example there is only a configure script in /var/tmp/portage/media-plugins/gst-transcoder-1.8.2-r1/work/gst-transcoder-1.8.2 folder and is autodetected by YCM-Generator. A build.ninja file is located in /var/tmp/portage/media-plugins/gst-transcoder-1.8.2-r1/work/gst-transcoder-1.8.2/mesonbuild folder.

We are working on that. Feel free to merge your changes.

The example reference script used it that way.

Code completion as in looking outside of the current opened buffers in nano is feature complete but the entire feature set of the completer commands is not feature complete. The UX could also be improved.

GPL version 3 or newer

It is GPL version 3 or newer

Add better user interface or user interaction. Emacs-ycmd is a good example.

Fix bugs or improve the speed. Solve why clang/llvm 3.9.1 doesn't show FixIts 100% of the time as expected.

After the UX has been polished and all the features are feature complete. If they do not want to include this patchset, we will fork nano. I want this merged eventually if possible or someone do it if I am gone or no longer working on it.

Yes you can, but you need to change the src/Makefile.am. Rerun autogen.sh. Do configure again specifying features then make. Just keep the binary only. I recommend installing both since nano-ycmd is still a work in progress.

If you compiled nano-ycmd with --enable-debug then you can redirect the stderr to a file to inspect it later. You should use --disable-debug if you are not a developer.

For example:

nano 2>/tmp/out.txt

This is a security precaution against automatically running a malicious compromised script or against exfiltrating sensitive data to an unauthorized threat actor. Before accepting it, you should inspect the contents carefully from top to bottom for suspicious code. Do not accept if it contains unauthorized domains, obfuscated text, attempts to touch sensitive data, attempts to access the network, etc.

ycmd will run this file after it has been confirmed safe to use by you in order for ycmd to work on this kind of project or this type of programming language.

To add popup support, compile add --enable-ycmd-popup to configure.

Optionally these environment variables before calling nano.

• NANO_YCMD_UI_MODE - Set to bottom or popup to choose between classic bottom bar UI mode or popup UI mode.
• NANO_YCMD_COMPLETION_LIMIT - Set to 3-10 to control the number of rows suggestions to choose for popup UI mode.

The popup UI mode is a new introduction. Features from the classic mode still need to be integrated with the popup UI. The popup support is enabled by default.

To use it, press <CTRL>-Space for the word you are trying to complete.

There is a limit on the string buffers. This limit controls how much data can be processed by string functions to a mitigate an availability attack. It is set by an environment variable before calling nano. It is to prevent a buffer overflow or calling unbounded strlen to unreasonable limit.

• NANO_YCMD_SMAX - Set between 1024 - 10485760 (or 1KB - 10 MB) to control buffer size. The default is 1048576 (1 MB).

To increase the mitigation against path traversal vulnerability pass a semicolon (;) list of dir paths to depenencies using --with-bin-safe-paths= and --with-lib-safe-paths=. This is to mitigate against a misconfiguration of default_settings.json that leads to Code Execution (CE), Privilege Escalation (PE), Data Tampering (DT), Information Disclosure (ID), Denial of Service (DoS). In addition mitigate against LD_PRELOAD hijack. For LD_PRELOAD, it is restricted to allow only Scudo and libsandbox with extra path prefix checks to prevent path traversal attack and CE, PE, DT, ID, DoS. Provide only the absolute paths to the bin folders or library. You can use realpath to resolve relative paths.

The directories for YCMD_PATH, YCMD_PYTHON_PATH, YCMG_PYTHON_PATH, GOCODE_PATH, GODEF_PATH, RUST_SRC_PATH, RACERD_PATH, YCMG_PATH, COMPDB_PATH, NINJA_PATH should be added to --with-bin-safe-paths.

Example:

--with-bin-safe-paths="/usr/lib/python3.11/site-packages/ycmd/48/third_party/clangd/output/bin;/usr/lib/python3.11/site-packages/ycmd/48/third_party/go/bin;/usr/lib/python3.11/site-packages/ycmd/48/third_party/gocode;/usr/lib/python3.11/site-packages/ycmd/48/third_party/godef;/usr/lib/python3.11/site-packages/ycmd/48/third_party/omnisharp-roslyn;/usr/lib/python3.11/site-packages/ycmd/48/third_party/omnisharp-roslyn/bin;/usr/lib/python3.11/site-packages/ycmd/48/third_party/racerd;/usr/lib/python3.11/site-packages/ycmd/48/third_party/rls/bin;/usr/lib/python3.11/site-packages/ycmd/48/third_party/rust-analyzer;/usr/lib/python3.11/site-packages/ycmd/48/third_party/tsserver/node_modules/typescript/bin"

--with-lib-safe-paths="/usr/lib64;/usr/lib/clang/18/lib/linux"

If --with-scudo-lib= is used, if Scudo is recompiled or updated, nano-ycmd must be recompiled to update the fingerprint associated with Scudo.

marchelzo and twkm from freenode ##C channel for the clear excess stdin fix.

Also see --version or

1. Click fork at the top of this page to create a repository on your account
2. git clone https://github.com/orsonteodoro/nano-ycmd.git
3. cd into folder
4. git checkout -b myfeaturename
5. make changes
6. git commit -m "My description here"
7. git push -u origin myfeaturename
8. go to your repository
9. make pull request