refactor: Reorganize parser directory

AGENTS.md

@@ -10,15 +10,16 @@ Lexer (logos) + parser (rowan) are resilient: collect errors, don't fail-fast.
 crates/
   plotnik-lib/         # Core library
     src/
-      ast/             # Syntax infrastructure
+      parser/          # Syntax infrastructure
         lexer.rs       # Token definitions (logos)
-        syntax_kind.rs # SyntaxKind enum
-        nodes.rs       # Typed AST wrappers over CST
-        parser/
-          core.rs      # Parser infrastructure
-          grammar.rs   # Grammar rules
-          error.rs     # Parse errors
-          tests/       # Parser tests (snapshots)
+        cst.rs         # SyntaxKind enum
+        ast.rs         # Typed AST wrappers over CST
+        core.rs        # Parser infrastructure
+        grammar.rs     # Grammar rules
+        error.rs       # Parse errors
+        invariants.rs  # Parser invariant checks
+        mod.rs         # Re-exports, Parse struct, parse()
+        tests/         # Parser tests (snapshots)
       query/           # Query processing
         mod.rs         # Query struct, new(), pipeline
         dump.rs        # dump_* debug output methods
@@ -38,7 +39,7 @@ docs/
 ## Pipeline
 
 ```rust
-ast::parse()                      // Parse → CST
+parser::parse()                   // Parse → CST
 alt_kind::validate()              // Validate alternation kinds
 named_defs::resolve()             // Resolve names → SymbolTable
 ref_cycles::validate()            // Validate recursion termination
@@ -97,7 +98,7 @@ Stages: `Parse` → `Validate` → `Resolve` → `Escape`. Use `Query::errors_fo
 - New scopes only from captured `{...}@s` or `[...]@c`
 - `?`/`*`/`+` = optional/list/non-empty list
 
-## AST Layer (`ast/nodes.rs`)
+## AST Layer (`parser/ast.rs`)
 
 Types: `Root`, `Def`, `Tree`, `Ref`, `Str`, `Alt`, `Branch`, `Seq`, `Capture`, `Type`, `Quantifier`, `Field`, `NegatedField`, `Wildcard`, `Anchor`, `Expr`
 

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

@@ -4,7 +4,7 @@ use std::fs;
 use std::io::{self, Read};
 
 use plotnik_lib::Query;
-use plotnik_lib::ast::RenderOptions;
+use plotnik_lib::RenderOptions;
 
 use source::{dump_source, load_source, parse_tree, resolve_lang};
 

crates/plotnik-lib/src/lib.rs

@@ -17,10 +17,10 @@
 
 #![cfg_attr(coverage_nightly, feature(coverage_attribute))]
 
-pub mod ast;
+pub mod parser;
 pub mod query;
 
-pub use ast::{Diagnostic, RenderOptions, Severity};
+pub use parser::{Diagnostic, RenderOptions, Severity};
 pub use query::{Query, QueryBuilder};
 
 /// Errors that can occur during query parsing.

crates/plotnik-lib/src/ast/nodes.rs → crates/plotnik-lib/src/parser/ast.rs

@@ -3,7 +3,7 @@
 //! Each struct wraps a `SyntaxNode` and provides typed accessors.
 //! Cast is infallible for correct `SyntaxKind` - validation happens elsewhere.
 
-use super::syntax_kind::{SyntaxKind, SyntaxNode, SyntaxToken};
+use super::cst::{SyntaxKind, SyntaxNode, SyntaxToken};
 
 macro_rules! ast_node {
     ($name:ident, $kind:ident) => {

crates/plotnik-lib/src/ast/parser/core.rs → crates/plotnik-lib/src/parser/core.rs

@@ -9,12 +9,12 @@
 
 use rowan::{Checkpoint, GreenNode, GreenNodeBuilder, TextRange, TextSize};
 
+use super::cst::token_sets::ROOT_EXPR_FIRST;
+use super::cst::{SyntaxKind, TokenSet};
 use super::error::{Diagnostic, Fix, RelatedInfo};
+use super::lexer::{Token, token_text};
 
 use crate::Error;
-use crate::ast::lexer::{Token, token_text};
-use crate::ast::syntax_kind::token_sets::ROOT_EXPR_FIRST;
-use crate::ast::syntax_kind::{SyntaxKind, TokenSet};
 
 const DEFAULT_EXEC_FUEL: u32 = 1_000_000;
 const DEFAULT_RECURSION_FUEL: u32 = 4096;

crates/plotnik-lib/src/ast/syntax_kind_tests.rs → crates/plotnik-lib/src/parser/cst_tests.rs

@@ -1,4 +1,4 @@
-use crate::ast::syntax_kind::{QLang, SyntaxKind::*, TokenSet};
+use crate::parser::cst::{QLang, SyntaxKind::*, TokenSet};
 use rowan::Language;
 
 #[test]

crates/plotnik-lib/src/ast/parser/error_tests.rs → crates/plotnik-lib/src/parser/error_tests.rs

@@ -1,4 +1,4 @@
-use super::*;
+use super::error::*;
 use rowan::TextRange;
 
 #[test]

crates/plotnik-lib/src/ast/parser/grammar.rs → crates/plotnik-lib/src/parser/grammar.rs

@@ -9,11 +9,11 @@ use super::core::Parser;
 use super::error::{Fix, RelatedInfo};
 use super::invariants::assert_nonempty;
 
-use crate::ast::lexer::token_text;
-use crate::ast::syntax_kind::token_sets::{
+use super::cst::token_sets::{
     ALT_RECOVERY, EXPR_FIRST, QUANTIFIERS, SEPARATORS, SEQ_RECOVERY, TREE_RECOVERY,
 };
-use crate::ast::syntax_kind::{SyntaxKind, TokenSet};
+use super::cst::{SyntaxKind, TokenSet};
+use super::lexer::token_text;
 
 impl Parser<'_> {
     pub fn parse_root(&mut self) {

crates/plotnik-lib/src/ast/parser/invariants.rs → crates/plotnik-lib/src/parser/invariants.rs

@@ -3,7 +3,7 @@
 #![cfg_attr(coverage_nightly, coverage(off))]
 
 use super::core::Parser;
-use crate::ast::syntax_kind::SyntaxKind;
+use super::cst::SyntaxKind;
 
 impl Parser<'_> {
     #[inline]

crates/plotnik-lib/src/ast/lexer.rs → crates/plotnik-lib/src/parser/lexer.rs

@@ -11,7 +11,7 @@ use logos::Logos;
 use rowan::TextRange;
 use std::ops::Range;
 
-use super::syntax_kind::SyntaxKind;
+use super::cst::SyntaxKind;
 
 /// Zero-copy token: kind + span, text retrieved via [`token_text`] when needed.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]

crates/plotnik-lib/src/ast/parser/mod.rs → crates/plotnik-lib/src/parser/mod.rs

@@ -1,4 +1,4 @@
-//! Resilient LL parser for the query language.
+//! Parser infrastructure for the query language.
 //!
 //! # Architecture
 //!
@@ -20,43 +20,47 @@
 //! 4. On recursion limit, remaining input goes into single Error node
 //!
 //! However, fuel exhaustion (exec_fuel, recursion_fuel) returns an error immediately.
-//!
-//! # Grammar (EBNF-ish)
-//!
-//! ```text
-//! root       = expr*
-//! expr       = tree | alternation | wildcard | anon_node
-//!            | anchor | negated_field | field | ident
-//! tree       = "(" [node_type] expr* ")"
-//! alternation= "[" expr* "]"
-//! wildcard   = "_"
-//! anon_node  = STRING
-//! capture    = "@" LOWER_IDENT
-//! anchor     = "."
-//! negated_field = "!" IDENT
-//! field      = IDENT ":" expr
-//! quantifier = expr ("*" | "+" | "?" | "*?" | "+?" | "??")
-//! capture    = expr "@" IDENT ["::" TYPE]
-//! ```
+
+pub mod ast;
+pub mod cst;
+pub mod lexer;
 
 mod core;
 mod error;
 mod grammar;
 mod invariants;
 
+#[cfg(test)]
+mod ast_tests;
+#[cfg(test)]
+mod cst_tests;
+#[cfg(test)]
+mod error_tests;
+#[cfg(test)]
+mod lexer_tests;
+#[cfg(test)]
+mod tests;
+
+// Re-exports from cst (was syntax_kind)
+pub use cst::{SyntaxKind, SyntaxNode, SyntaxToken};
+
+// Re-exports from ast (was nodes)
+pub use ast::{
+    Alt, AltKind, Anchor, Branch, Capture, Def, Expr, Field, NegatedField, Quantifier, Ref, Root,
+    Seq, Str, Tree, Type, Wildcard,
+};
+
+// Re-exports from error
 pub use error::{
     Diagnostic, ErrorStage, Fix, RelatedInfo, RenderOptions, Severity, SyntaxError,
     render_diagnostics, render_errors,
 };
 
+// Internal use
 pub(crate) use core::Parser;
 
-use super::lexer::lex;
-use super::syntax_kind::SyntaxNode;
 use crate::Result;
-
-#[cfg(test)]
-mod error_tests;
+use lexer::lex;
 
 /// Parse result containing the green tree and any errors.
 ///
@@ -79,7 +83,7 @@ impl Parse {
         SyntaxNode::new_root(self.inner.green.clone())
     }
 
-    pub fn errors(&self) -> &[SyntaxError] {
+    pub fn errors(&self) -> &[Diagnostic] {
         &self.inner.errors
     }
 
@@ -106,6 +110,3 @@ pub(crate) fn parse_with_parser(mut parser: Parser) -> Result<Parse> {
         inner: parser.finish()?,
     })
 }
-
-#[cfg(test)]
-mod tests;

crates/plotnik-lib/src/ast/parser/tests/json_serialization_tests.rs → crates/plotnik-lib/src/parser/tests/json_serialization_tests.rs

@@ -1,4 +1,4 @@
-use crate::ast::parser::parse;
+use crate::parser::parse;
 
 #[test]
 fn error_json_serialization() {

crates/plotnik-lib/src/query/alt_kind.rs

@@ -8,8 +8,8 @@ use rowan::TextRange;
 use super::invariants::{
     assert_alt_no_bare_exprs, assert_root_no_bare_exprs, ensure_both_branch_kinds,
 };
-use crate::ast::{Alt, AltKind, Branch, Expr, Root};
-use crate::ast::{Diagnostic, ErrorStage, RelatedInfo};
+use crate::parser::{Alt, AltKind, Branch, Expr, Root};
+use crate::parser::{Diagnostic, ErrorStage, RelatedInfo};
 
 pub fn validate(root: &Root) -> Vec<Diagnostic> {
     let mut errors = Vec::new();

crates/plotnik-lib/src/query/dump.rs

@@ -1,7 +1,7 @@
 #[cfg(test)]
 mod test_helpers {
     use crate::Query;
-    use crate::ast::{RenderOptions, render_diagnostics};
+    use crate::parser::{RenderOptions, render_diagnostics};
 
     impl Query<'_> {
         pub fn dump_cst(&self) -> String {

crates/plotnik-lib/src/query/errors.rs

@@ -1,4 +1,4 @@
-use crate::ast::{Diagnostic, ErrorStage, RenderOptions, Severity, render_diagnostics};
+use crate::parser::{Diagnostic, ErrorStage, RenderOptions, Severity, render_diagnostics};
 
 use super::Query;
 

crates/plotnik-lib/src/query/errors_tests.rs

@@ -1,5 +1,5 @@
 use super::Query;
-use crate::ast::{ErrorStage, RenderOptions, Severity};
+use crate::parser::{ErrorStage, RenderOptions, Severity};
 
 #[test]
 fn diagnostics_alias() {

crates/plotnik-lib/src/query/invariants.rs

@@ -2,7 +2,7 @@
 
 #![cfg_attr(coverage_nightly, coverage(off))]
 
-use crate::ast::{Alt, Branch, Ref, Root, SyntaxNode, SyntaxToken};
+use crate::parser::{Alt, Branch, Ref, Root, SyntaxNode, SyntaxToken};
 
 #[inline]
 pub fn assert_root_no_bare_exprs(root: &Root) {

crates/plotnik-lib/src/query/mod.rs

@@ -29,9 +29,9 @@ mod shape_cardinalities_tests;
 use std::collections::HashMap;
 
 use crate::Result;
-use crate::ast::lexer::lex;
-use crate::ast::parser::{self, Parser};
-use crate::ast::{Diagnostic, Parse, Root, SyntaxNode};
+use crate::parser::lexer::lex;
+use crate::parser::{self, Parser};
+use crate::parser::{Diagnostic, Parse, Root, SyntaxNode};
 use named_defs::SymbolTable;
 use shape_cardinalities::ShapeCardinality;
 

crates/plotnik-lib/src/query/named_defs.rs

@@ -7,8 +7,8 @@
 use indexmap::{IndexMap, IndexSet};
 use rowan::TextRange;
 
-use crate::ast::{Diagnostic, ErrorStage};
-use crate::ast::{Expr, Ref, Root};
+use crate::parser::{Diagnostic, ErrorStage};
+use crate::parser::{Expr, Ref, Root};
 
 #[derive(Debug, Clone)]
 pub struct SymbolTable {

crates/plotnik-lib/src/query/printer.rs

@@ -2,7 +2,7 @@ use std::fmt::Write;
 
 use rowan::NodeOrToken;
 
-use crate::ast::{self, SyntaxNode};
+use crate::parser::{self as ast, SyntaxNode};
 
 use super::Query;
 use super::shape_cardinalities::ShapeCardinality;

crates/plotnik-lib/src/query/ref_cycles.rs

@@ -7,8 +7,8 @@ use indexmap::{IndexMap, IndexSet};
 use rowan::TextRange;
 
 use super::named_defs::SymbolTable;
-use crate::ast::{Def, Expr, Root, SyntaxKind};
-use crate::ast::{Diagnostic, ErrorStage, RelatedInfo};
+use crate::parser::{Def, Expr, Root, SyntaxKind};
+use crate::parser::{Diagnostic, ErrorStage, RelatedInfo};
 
 pub fn validate(root: &Root, symbols: &SymbolTable) -> Vec<Diagnostic> {
     let sccs = find_sccs(symbols);

crates/plotnik-lib/src/query/shape_cardinalities.rs

@@ -11,8 +11,8 @@ use super::invariants::{
     assert_ref_in_symbols, ensure_ref_body, ensure_ref_name, panic_unexpected_node,
 };
 use super::named_defs::SymbolTable;
-use crate::ast::{Branch, Def, Expr, Field, Ref, Root, Seq, SyntaxNode, Type};
-use crate::ast::{Diagnostic, ErrorStage};
+use crate::parser::{Branch, Def, Expr, Field, Ref, Root, Seq, SyntaxNode, Type};
+use crate::parser::{Diagnostic, ErrorStage};
 use std::collections::HashMap;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]