feat: Add lang list and lang dump commands

AGENTS.md

@@ -172,15 +172,16 @@ docs/
 
 Run: `cargo run -p plotnik -- <command>`
 
-| Command | Purpose                         |
-| ------- | ------------------------------- |
-| `ast`   | Show AST of query and/or source |
-| `check` | Validate query                  |
-| `dump`  | Show compiled bytecode          |
-| `infer` | Generate TypeScript types       |
-| `exec`  | Execute query, output JSON      |
-| `trace` | Trace execution for debugging   |
-| `langs` | List supported languages        |
+| Command     | Purpose                         |
+| ----------- | ------------------------------- |
+| `ast`       | Show AST of query and/or source |
+| `check`     | Validate query                  |
+| `dump`      | Show compiled bytecode          |
+| `infer`     | Generate TypeScript types       |
+| `exec`      | Execute query, output JSON      |
+| `trace`     | Trace execution for debugging   |
+| `lang list` | List supported languages        |
+| `lang dump` | Dump grammar for a language     |
 
 ## ast
 
@@ -265,12 +266,14 @@ cargo run -p plotnik -- trace query.ptk app.ts --no-result -vv
 
 Options: `-v` (verbose), `-vv` (very verbose), `--no-result`, `--fuel <N>`
 
-## langs
+## lang
 
-List supported tree-sitter languages.
+Language information and grammar tools.
 
 ```sh
-cargo run -p plotnik -- langs
+cargo run -p plotnik -- lang list                  # List languages with aliases
+cargo run -p plotnik -- lang dump json             # Dump JSON grammar
+cargo run -p plotnik -- lang dump typescript       # Dump TypeScript grammar
 ```
 
 # Coding Rules

crates/plotnik-cli/Cargo.toml

@@ -240,4 +240,7 @@ plotnik-lib = { version = "0.2", path = "../plotnik-lib" }
 arborium-tree-sitter = "2.5.0"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-thiserror = "2.0"
+thiserror = "2.0"
+
+[dev-dependencies]
+insta = "=1.46.0"

crates/plotnik-cli/src/cli/commands.rs

@@ -53,7 +53,7 @@ pub fn build_cli() -> Command {
         .subcommand(infer_command())
         .subcommand(exec_command())
         .subcommand(trace_command())
-        .subcommand(langs_command())
+        .subcommand(lang_command())
 }
 
 /// Show AST of query and/or source file.
@@ -260,7 +260,29 @@ pub fn trace_command() -> Command {
     )
 }
 
+/// Language information commands.
+pub fn lang_command() -> Command {
+    Command::new("lang")
+        .about("Language information and grammar dump")
+        .subcommand_required(true)
+        .arg_required_else_help(true)
+        .subcommand(lang_list_command())
+        .subcommand(lang_dump_command())
+}
+
 /// List supported languages.
-pub fn langs_command() -> Command {
-    Command::new("langs").about("List supported languages")
+fn lang_list_command() -> Command {
+    Command::new("list").about("List supported languages with aliases")
+}
+
+/// Dump grammar for a language.
+fn lang_dump_command() -> Command {
+    Command::new("dump")
+        .about("Dump grammar in Plotnik-like syntax")
+        .arg(
+            clap::Arg::new("lang")
+                .help("Language name or alias")
+                .required(true)
+                .index(1),
+        )
 }

crates/plotnik-cli/src/cli/dispatch.rs

@@ -310,14 +310,26 @@ impl From<TraceParams> for TraceArgs {
     }
 }
 
-pub struct LangsParams;
+pub struct LangListParams;
 
-impl LangsParams {
+impl LangListParams {
     pub fn from_matches(_m: &ArgMatches) -> Self {
         Self
     }
 }
 
+pub struct LangDumpParams {
+    pub lang: String,
+}
+
+impl LangDumpParams {
+    pub fn from_matches(m: &ArgMatches) -> Self {
+        Self {
+            lang: m.get_one::<String>("lang").cloned().unwrap(),
+        }
+    }
+}
+
 /// Parse --color flag into ColorChoice.
 fn parse_color(m: &ArgMatches) -> ColorChoice {
     match m.get_one::<String>("color").map(|s| s.as_str()) {

crates/plotnik-cli/src/cli/mod.rs

@@ -7,7 +7,8 @@ mod dispatch_tests;
 
 pub use commands::build_cli;
 pub use dispatch::{
-    AstParams, CheckParams, DumpParams, ExecParams, InferParams, LangsParams, TraceParams,
+    AstParams, CheckParams, DumpParams, ExecParams, InferParams, LangDumpParams, LangListParams,
+    TraceParams,
 };
 
 /// Color output mode for CLI commands.