v-tools

# V tools Most of V's command surface is reached by habit. This is the part that is not: commands that answer a question, shrink a failure, or keep a project honest. `v help topics` lists everything; the ones below are the ones worth knowing. ## Look at code before changing it ```sh v ast -p file.v # print the AST as JSON; without -p it writes file.json v where fn NAME # where a symbol is declared; also struct, method, enum, const v mod why MODULE # which import chain pulls a module into the build ``` `v where` finds declarations only, and searches vlib as well as the project; `-mod main` keeps it to the project. Where a symbol is used is answered by the `v_references` tool of the MCP server. `v mod why` is the one that answers a question people otherwise guess at: nothing in `v.mod` records what a build actually reaches, so a dependency can outlive the code that needed it. Through the MCP server the same ground is covered with less shell work; see v-mcp. ## Shrink a compiler error ```sh v reduce -m 'text of the error' file.v # the smallest source that still errors ``` Without `-m`, `v reduce` only looks for a C compilation error, so a checker error such as `unknown function: nope` needs its text passed in. The reduction lands in `rpdc_<file>.v` (`rpdc_bad.v` for `bad.v`) in the current directory. Pair it with `v bug`, which opens a prefilled issue, and the report carries a minimal reproducer instead of the file you happened to be editing. ## Project hygiene ```sh v missdoc src/ # public functions with no documentation comment v check-md README.md # are the ```v blocks in this markdown correct? v bump --patch # or --minor / --major; bumps the version in v.mod v git-fmt-hook install # format on commit ``` `v check-md` is worth knowing about specifically: it compiles the V examples in a markdown file, which catches a snippet that stopped compiling long after anyone looked at the prose. `v missdoc` takes `-p` to include private functions and `-t` to include function tags. ## Embed binary files ```sh v bin2v -m main -w assets.v assets/logo.png assets/font.ttf ``` Writes each file into `assets.v` as a byte-array constant (`logo_png`, with its length in `logo_png_len`), so a program carries its images and fonts instead of reading them from disk at runtime. Without `-w` the source goes to stdout. The constants are private, so generate them into the module that uses them. For a single file, `$embed_file('assets/logo.png')` does the same at compile time. ## Shell integration ```sh v complete setup bash # print the completion setup script; bash, fish, zsh, powershell ``` Load it from the shell's startup file; for bash, add `source /dev/stdin <<<"$(v complete setup bash)"` to `~/.bashrc`. ## Time, repeat, retry ```sh v time CMD # how long CMD took, and what it exited with v repeat CMD... # repeat commands and collect statistics v retry CMD # rerun until it succeeds, for up to 10 retries or 10 minutes ``` `v retry` is the one to reach for when a flaky network call or a busy port is the thing in the way; `-r` and `-t` change its limits. `v time` is the one when the question is which of two approaches is actually cheaper. ## Compiler upkeep ```sh v up # update V itself v clean # remove what a default build leaves behind v env # the environment variables that steer the compiler v tracev # a tracing build of the compiler ``` `v env` is the first thing to read when the compiler or one of its tools behaves differently on another machine, because most of that behaviour is an environment variable. `v help build-c` documents the C-backend flags — `-cc`, `-glibc`, `-musl` — when the C toolchain itself is the thing in question. ## Other commands worth knowing ```sh v ls # install and run the V language server v repl # the V REPL v watch file.v # rebuild when the sources it needs change v crun file.v # build and run, keeping the executable v tool NAME # run a tool module by name v share file.v # send a .v file to the V Playground v download URL # fetch a file over http or https v symlink # put v on PATH ``` `v download -RD URL` also runs the downloaded file with `v run` and deletes it afterwards. That executes remote code, so read the file first. Package management is `v search`, `v show`, `v list`, `v outdated`, `v update`, `v upgrade` and `v remove`, over the VPM registry. ## The command that installs this skill ```sh v skills list # what is bundled, and what is installed v skills add v-tools # install one v skills update # refresh what a new V revision changed ``` ## Related Skills - **Scripts**: see [v-scripts](../v-scripts/SKILL.md) for `.vsh` script mode and its executable cache. - **The build and test loop**: see [v-workflow](../v-workflow/SKILL.md). - **The language rules**: see [v-lang](../v-lang/SKILL.md). - **Reading a project through the compiler**: see [v-mcp](../v-mcp/SKILL.md) for declarations, references and diagnostics without shell commands.