internal: make name consistent with usage

crates/hir_def/src/attr.rs

@@ -695,7 +695,8 @@ impl Attr {
         hygiene: &Hygiene,
         id: AttrId,
     ) -> Option<Attr> {
-        let (parse, _) = mbe::token_tree_to_syntax_node(tt, mbe::FragmentKind::MetaItem).ok()?;
+        let (parse, _) =
+            mbe::token_tree_to_syntax_node(tt, mbe::ParserEntryPoint::MetaItem).ok()?;
         let ast = ast::Meta::cast(parse.syntax_node())?;
 
         Self::from_src(db, ast, hygiene, id)

crates/hir_expand/src/builtin_derive.rs

@@ -72,7 +72,7 @@ struct BasicAdtInfo {
 }
 
 fn parse_adt(tt: &tt::Subtree) -> Result<BasicAdtInfo, mbe::ExpandError> {
-    let (parsed, token_map) = mbe::token_tree_to_syntax_node(tt, mbe::FragmentKind::Items)?; // FragmentKind::Items doesn't parse attrs?
+    let (parsed, token_map) = mbe::token_tree_to_syntax_node(tt, mbe::ParserEntryPoint::Items)?; // FragmentKind::Items doesn't parse attrs?
     let macro_items = ast::MacroItems::cast(parsed.syntax_node()).ok_or_else(|| {
         debug!("derive node didn't parse");
         mbe::ExpandError::UnexpectedToken

crates/hir_expand/src/db.rs

@@ -444,12 +444,12 @@ fn token_tree_to_syntax_node(
     tt: &tt::Subtree,
     expand_to: ExpandTo,
 ) -> Result<(Parse<SyntaxNode>, mbe::TokenMap), ExpandError> {
-    let fragment = match expand_to {
+    let entry_point = match expand_to {
-        ExpandTo::Statements => mbe::FragmentKind::Statements,
+        ExpandTo::Statements => mbe::ParserEntryPoint::Statements,
-        ExpandTo::Items => mbe::FragmentKind::Items,
+        ExpandTo::Items => mbe::ParserEntryPoint::Items,
-        ExpandTo::Pattern => mbe::FragmentKind::Pattern,
+        ExpandTo::Pattern => mbe::ParserEntryPoint::Pattern,
-        ExpandTo::Type => mbe::FragmentKind::Type,
+        ExpandTo::Type => mbe::ParserEntryPoint::Type,
-        ExpandTo::Expr => mbe::FragmentKind::Expr,
+        ExpandTo::Expr => mbe::ParserEntryPoint::Expr,
     };
-    mbe::token_tree_to_syntax_node(tt, fragment)
+    mbe::token_tree_to_syntax_node(tt, entry_point)
 }

crates/hir_expand/src/eager.rs

@@ -131,7 +131,7 @@ pub fn expand_eager_macro(
     let arg_file_id = arg_id;
 
     let parsed_args = diagnostic_sink
-        .result(mbe::token_tree_to_syntax_node(&parsed_args, mbe::FragmentKind::Expr))?
+        .result(mbe::token_tree_to_syntax_node(&parsed_args, mbe::ParserEntryPoint::Expr))?
         .0;
     let result = eager_macro_recur(
         db,

crates/mbe/src/expander/matcher.rs

@@ -69,7 +69,7 @@ use crate::{
 };
 
 use super::ExpandResult;
-use parser::FragmentKind::*;
+use parser::ParserEntryPoint::*;
 use smallvec::{smallvec, SmallVec};
 use syntax::SmolStr;
 

crates/mbe/src/lib.rs

@@ -24,7 +24,7 @@ use crate::{
 };
 
 // FIXME: we probably should re-think  `token_tree_to_syntax_node` interfaces
-pub use ::parser::FragmentKind;
+pub use ::parser::ParserEntryPoint;
 pub use tt::{Delimiter, DelimiterKind, Punct};
 
 #[derive(Debug, PartialEq, Eq)]

crates/mbe/src/syntax_bridge.rs

@@ -13,7 +13,7 @@ use syntax::{
 use tt::buffer::{Cursor, TokenBuffer};
 
 use crate::{
-    subtree_source::SubtreeTokenSource, tt_iter::TtIter, ExpandError, FragmentKind, TokenMap,
+    subtree_source::SubtreeTokenSource, tt_iter::TtIter, ExpandError, ParserEntryPoint, TokenMap,
 };
 
 /// Convert the syntax node to a `TokenTree` (what macro
@@ -49,7 +49,7 @@ pub fn syntax_node_to_token_tree_censored(
 
 pub fn token_tree_to_syntax_node(
     tt: &tt::Subtree,
-    fragment_kind: FragmentKind,
+    entry_point: ParserEntryPoint,
 ) -> Result<(Parse<SyntaxNode>, TokenMap), ExpandError> {
     let buffer = match tt {
         tt::Subtree { delimiter: None, token_trees } => {
@@ -59,7 +59,7 @@ pub fn token_tree_to_syntax_node(
     };
     let mut token_source = SubtreeTokenSource::new(&buffer);
     let mut tree_sink = TtTreeSink::new(buffer.begin());
-    parser::parse_fragment(&mut token_source, &mut tree_sink, fragment_kind);
+    parser::parse(&mut token_source, &mut tree_sink, entry_point);
     if tree_sink.roots.len() != 1 {
         return Err(ExpandError::ConversionError);
     }
@@ -100,7 +100,7 @@ pub fn parse_exprs_with_sep(tt: &tt::Subtree, sep: char) -> Vec<tt::Subtree> {
     let mut res = Vec::new();
 
     while iter.peek_n(0).is_some() {
-        let expanded = iter.expect_fragment(FragmentKind::Expr);
+        let expanded = iter.expect_fragment(ParserEntryPoint::Expr);
         if expanded.err.is_some() {
             break;
         }
@@ -790,7 +790,7 @@ mod tests {
             "#,
         )
         .expand_tt("stmts!();");
-        assert!(token_tree_to_syntax_node(&expansion, FragmentKind::Expr).is_err());
+        assert!(token_tree_to_syntax_node(&expansion, ParserEntryPoint::Expr).is_err());
     }
 
     #[test]
@@ -823,7 +823,7 @@ mod tests {
         let source_file = ast::SourceFile::parse("struct Foo { a: x::Y }").ok().unwrap();
         let struct_def = source_file.syntax().descendants().find_map(ast::Struct::cast).unwrap();
         let tt = syntax_node_to_token_tree(struct_def.syntax()).0;
-        token_tree_to_syntax_node(&tt, FragmentKind::Item).unwrap();
+        token_tree_to_syntax_node(&tt, ParserEntryPoint::Item).unwrap();
     }
 
     #[test]

crates/mbe/src/tests.rs

@@ -6,7 +6,7 @@ use std::fmt::Write;
 use syntax::{ast, AstNode, NodeOrToken, SyntaxNode, WalkEvent};
 use test_utils::assert_eq_text;
 
-use crate::FragmentKind;
+use crate::ParserEntryPoint;
 
 use super::*;
 
@@ -44,13 +44,16 @@ macro_rules! impl_fixture {
             #[allow(unused)]
             fn expand_items(&self, invocation: &str) -> SyntaxNode {
                 let expanded = self.expand_tt(invocation);
-                token_tree_to_syntax_node(&expanded, FragmentKind::Items).unwrap().0.syntax_node()
+                token_tree_to_syntax_node(&expanded, ParserEntryPoint::Items)
+                    .unwrap()
+                    .0
+                    .syntax_node()
             }
 
             #[allow(unused)]
             fn expand_statements(&self, invocation: &str) -> SyntaxNode {
                 let expanded = self.expand_tt(invocation);
-                token_tree_to_syntax_node(&expanded, FragmentKind::Statements)
+                token_tree_to_syntax_node(&expanded, ParserEntryPoint::Statements)
                     .unwrap()
                     .0
                     .syntax_node()
@@ -59,7 +62,10 @@ macro_rules! impl_fixture {
             #[allow(unused)]
             fn expand_expr(&self, invocation: &str) -> SyntaxNode {
                 let expanded = self.expand_tt(invocation);
-                token_tree_to_syntax_node(&expanded, FragmentKind::Expr).unwrap().0.syntax_node()
+                token_tree_to_syntax_node(&expanded, ParserEntryPoint::Expr)
+                    .unwrap()
+                    .0
+                    .syntax_node()
             }
 
             #[allow(unused)]
@@ -76,17 +82,17 @@ macro_rules! impl_fixture {
             }
 
             fn assert_expand_items(&self, invocation: &str, expected: &str) -> &$name {
-                self.assert_expansion(FragmentKind::Items, invocation, expected);
+                self.assert_expansion(ParserEntryPoint::Items, invocation, expected);
                 self
             }
 
             #[allow(unused)]
             fn assert_expand_statements(&self, invocation: &str, expected: &str) -> &$name {
-                self.assert_expansion(FragmentKind::Statements, invocation, expected);
+                self.assert_expansion(ParserEntryPoint::Statements, invocation, expected);
                 self
             }
 
-            fn assert_expansion(&self, kind: FragmentKind, invocation: &str, expected: &str) {
+            fn assert_expansion(&self, kind: ParserEntryPoint, invocation: &str, expected: &str) {
                 let expanded = self.expand_tt(invocation);
                 assert_eq!(expanded.to_string(), expected);
 

crates/mbe/src/tests/expand.rs

@@ -1,4 +1,4 @@
-use ::parser::FragmentKind;
+use ::parser::ParserEntryPoint;
 use syntax::{
     SyntaxKind::{ERROR, IDENT},
     T,
@@ -55,7 +55,7 @@ macro_rules! foobar {
     )
     .expand_tt("foobar!(baz);");
 
-    let (node, token_map) = token_tree_to_syntax_node(&expanded, FragmentKind::Items).unwrap();
+    let (node, token_map) = token_tree_to_syntax_node(&expanded, ParserEntryPoint::Items).unwrap();
     let content = node.syntax_node().to_string();
 
     let get_text = |id, kind| -> String {

crates/mbe/src/tt_iter.rs

@@ -1,7 +1,7 @@
 //! A "Parser" structure for token trees. We use this when parsing a declarative
 //! macro definition into a list of patterns and templates.
 
-use crate::{subtree_source::SubtreeTokenSource, ExpandError, ExpandResult};
+use crate::{subtree_source::SubtreeTokenSource, ExpandError, ExpandResult, ParserEntryPoint};
 
 use parser::TreeSink;
 use syntax::SyntaxKind;
@@ -92,7 +92,7 @@ impl<'a> TtIter<'a> {
 
     pub(crate) fn expect_fragment(
         &mut self,
-        fragment_kind: parser::FragmentKind,
+        entry_point: ParserEntryPoint,
     ) -> ExpandResult<Option<tt::TokenTree>> {
         struct OffsetTokenSink<'a> {
             cursor: Cursor<'a>,
@@ -119,10 +119,10 @@ impl<'a> TtIter<'a> {
         let mut src = SubtreeTokenSource::new(&buffer);
         let mut sink = OffsetTokenSink { cursor: buffer.begin(), error: false };
 
-        parser::parse_fragment(&mut src, &mut sink, fragment_kind);
+        parser::parse(&mut src, &mut sink, entry_point);
 
         let mut err = if !sink.cursor.is_root() || sink.error {
-            Some(err!("expected {:?}", fragment_kind))
+            Some(err!("expected {:?}", entry_point))
         } else {
             None
         };

crates/parser/src/grammar.rs

@@ -44,20 +44,23 @@ use crate::{
     TokenSet,
 };
 
-pub(crate) fn root(p: &mut Parser) {
+pub(crate) mod entry_points {
-    let m = p.start();
-    p.eat(SHEBANG);
-    items::mod_contents(p, false);
-    m.complete(p, SOURCE_FILE);
-}
-
-/// Various pieces of syntax that can be parsed by macros by example
-pub(crate) mod fragments {
     use super::*;
 
-    pub(crate) use super::{
+    pub(crate) fn source_file(p: &mut Parser) {
-        expressions::block_expr, paths::type_path as path, patterns::pattern_single, types::type_,
+        let m = p.start();
-    };
+        p.eat(SHEBANG);
+        items::mod_contents(p, false);
+        m.complete(p, SOURCE_FILE);
+    }
+
+    pub(crate) use expressions::block_expr;
+
+    pub(crate) use paths::type_path as path;
+
+    pub(crate) use patterns::pattern_single as pattern;
+
+    pub(crate) use types::type_;
 
     pub(crate) fn expr(p: &mut Parser) {
         let _ = expressions::expr_with_attrs(p);
@@ -71,8 +74,8 @@ pub(crate) mod fragments {
         expressions::stmt(p, expressions::StmtWithSemi::Optional, false)
     }
 
-    pub(crate) fn opt_visibility(p: &mut Parser) {
+    pub(crate) fn visibility(p: &mut Parser) {
-        let _ = super::opt_visibility(p);
+        let _ = opt_visibility(p);
     }
 
     // Parse a meta item , which excluded [], e.g : #[ MetaItem ]

crates/parser/src/lib.rs

@@ -71,23 +71,13 @@ pub trait TreeSink {
     fn error(&mut self, error: ParseError);
 }
 
-fn parse_from_tokens<F>(token_source: &mut dyn TokenSource, tree_sink: &mut dyn TreeSink, f: F)
+/// rust-analyzer parser allows you to choose one of the possible entry points.
-where
+///
-    F: FnOnce(&mut parser::Parser),
+/// The primary consumer of this API are declarative macros, `$x:expr` matchers
-{
+/// are implemented by calling into the parser with non-standard entry point.
-    let mut p = parser::Parser::new(token_source);
-    f(&mut p);
-    let events = p.finish();
-    event::process(tree_sink, events);
-}
-
-/// Parse given tokens into the given sink as a rust file.
-pub fn parse(token_source: &mut dyn TokenSource, tree_sink: &mut dyn TreeSink) {
-    parse_from_tokens(token_source, tree_sink, grammar::root);
-}
-
 #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
-pub enum FragmentKind {
+pub enum ParserEntryPoint {
+    SourceFile,
     Path,
     Expr,
     Statement,
@@ -103,27 +93,37 @@ pub enum FragmentKind {
     Attr,
 }
 
-pub fn parse_fragment(
+/// Parse given tokens into the given sink as a rust file.
+pub fn parse_source_file(token_source: &mut dyn TokenSource, tree_sink: &mut dyn TreeSink) {
+    parse(token_source, tree_sink, ParserEntryPoint::SourceFile);
+}
+
+pub fn parse(
     token_source: &mut dyn TokenSource,
     tree_sink: &mut dyn TreeSink,
-    fragment_kind: FragmentKind,
+    entry_point: ParserEntryPoint,
 ) {
-    let parser: fn(&'_ mut parser::Parser) = match fragment_kind {
+    let entry_point: fn(&'_ mut parser::Parser) = match entry_point {
-        FragmentKind::Path => grammar::fragments::path,
+        ParserEntryPoint::SourceFile => grammar::entry_points::source_file,
-        FragmentKind::Expr => grammar::fragments::expr,
+        ParserEntryPoint::Path => grammar::entry_points::path,
-        FragmentKind::Type => grammar::fragments::type_,
+        ParserEntryPoint::Expr => grammar::entry_points::expr,
-        FragmentKind::Pattern => grammar::fragments::pattern_single,
+        ParserEntryPoint::Type => grammar::entry_points::type_,
-        FragmentKind::Item => grammar::fragments::item,
+        ParserEntryPoint::Pattern => grammar::entry_points::pattern,
-        FragmentKind::Block => grammar::fragments::block_expr,
+        ParserEntryPoint::Item => grammar::entry_points::item,
-        FragmentKind::Visibility => grammar::fragments::opt_visibility,
+        ParserEntryPoint::Block => grammar::entry_points::block_expr,
-        FragmentKind::MetaItem => grammar::fragments::meta_item,
+        ParserEntryPoint::Visibility => grammar::entry_points::visibility,
-        FragmentKind::Statement => grammar::fragments::stmt,
+        ParserEntryPoint::MetaItem => grammar::entry_points::meta_item,
-        FragmentKind::StatementOptionalSemi => grammar::fragments::stmt_optional_semi,
+        ParserEntryPoint::Statement => grammar::entry_points::stmt,
-        FragmentKind::Items => grammar::fragments::macro_items,
+        ParserEntryPoint::StatementOptionalSemi => grammar::entry_points::stmt_optional_semi,
-        FragmentKind::Statements => grammar::fragments::macro_stmts,
+        ParserEntryPoint::Items => grammar::entry_points::macro_items,
-        FragmentKind::Attr => grammar::fragments::attr,
+        ParserEntryPoint::Statements => grammar::entry_points::macro_stmts,
+        ParserEntryPoint::Attr => grammar::entry_points::attr,
     };
-    parse_from_tokens(token_source, tree_sink, parser)
+
+    let mut p = parser::Parser::new(token_source);
+    entry_point(&mut p);
+    let events = p.finish();
+    event::process(tree_sink, events);
 }
 
 /// A parsing function for a specific braced-block.

crates/syntax/src/lib.rs

@@ -173,52 +173,58 @@ impl SourceFile {
     }
 }
 
+// FIXME: `parse` functions shouldn't hang directly from AST nodes, and they
+// shouldn't return `Result`.
+//
+// We need a dedicated module for parser entry points, and they should always
+// return `Parse`.
+
 impl ast::Path {
     /// Returns `text`, parsed as a path, but only if it has no errors.
     pub fn parse(text: &str) -> Result<Self, ()> {
-        parsing::parse_text_fragment(text, parser::FragmentKind::Path)
+        parsing::parse_text_as(text, parser::ParserEntryPoint::Path)
     }
 }
 
 impl ast::Pat {
     /// Returns `text`, parsed as a pattern, but only if it has no errors.
     pub fn parse(text: &str) -> Result<Self, ()> {
-        parsing::parse_text_fragment(text, parser::FragmentKind::Pattern)
+        parsing::parse_text_as(text, parser::ParserEntryPoint::Pattern)
     }
 }
 
 impl ast::Expr {
     /// Returns `text`, parsed as an expression, but only if it has no errors.
     pub fn parse(text: &str) -> Result<Self, ()> {
-        parsing::parse_text_fragment(text, parser::FragmentKind::Expr)
+        parsing::parse_text_as(text, parser::ParserEntryPoint::Expr)
     }
 }
 
 impl ast::Item {
     /// Returns `text`, parsed as an item, but only if it has no errors.
     pub fn parse(text: &str) -> Result<Self, ()> {
-        parsing::parse_text_fragment(text, parser::FragmentKind::Item)
+        parsing::parse_text_as(text, parser::ParserEntryPoint::Item)
     }
 }
 
 impl ast::Type {
     /// Returns `text`, parsed as an type reference, but only if it has no errors.
     pub fn parse(text: &str) -> Result<Self, ()> {
-        parsing::parse_text_fragment(text, parser::FragmentKind::Type)
+        parsing::parse_text_as(text, parser::ParserEntryPoint::Type)
     }
 }
 
 impl ast::Attr {
     /// Returns `text`, parsed as an attribute, but only if it has no errors.
     pub fn parse(text: &str) -> Result<Self, ()> {
-        parsing::parse_text_fragment(text, parser::FragmentKind::Attr)
+        parsing::parse_text_as(text, parser::ParserEntryPoint::Attr)
     }
 }
 
 impl ast::Stmt {
     /// Returns `text`, parsed as statement, but only if it has no errors.
     pub fn parse(text: &str) -> Result<Self, ()> {
-        parsing::parse_text_fragment(text, parser::FragmentKind::StatementOptionalSemi)
+        parsing::parse_text_as(text, parser::ParserEntryPoint::StatementOptionalSemi)
     }
 }
 

crates/syntax/src/parsing.rs

@@ -20,7 +20,7 @@ pub(crate) fn parse_text(text: &str) -> (GreenNode, Vec<SyntaxError>) {
     let mut token_source = TextTokenSource::new(text, &tokens);
     let mut tree_sink = TextTreeSink::new(text, &tokens);
 
-    parser::parse(&mut token_source, &mut tree_sink);
+    parser::parse_source_file(&mut token_source, &mut tree_sink);
 
     let (tree, mut parser_errors) = tree_sink.finish();
     parser_errors.extend(lexer_errors);
@@ -29,9 +29,9 @@ pub(crate) fn parse_text(text: &str) -> (GreenNode, Vec<SyntaxError>) {
 }
 
 /// Returns `text` parsed as a `T` provided there are no parse errors.
-pub(crate) fn parse_text_fragment<T: AstNode>(
+pub(crate) fn parse_text_as<T: AstNode>(
     text: &str,
-    fragment_kind: parser::FragmentKind,
+    entry_point: parser::ParserEntryPoint,
 ) -> Result<T, ()> {
     let (tokens, lexer_errors) = tokenize(text);
     if !lexer_errors.is_empty() {
@@ -45,7 +45,7 @@ pub(crate) fn parse_text_fragment<T: AstNode>(
     // tokens. We arbitrarily give it a SourceFile.
     use parser::TreeSink;
     tree_sink.start_node(SyntaxKind::SOURCE_FILE);
-    parser::parse_fragment(&mut token_source, &mut tree_sink, fragment_kind);
+    parser::parse(&mut token_source, &mut tree_sink, entry_point);
     tree_sink.finish_node();
 
     let (tree, parser_errors) = tree_sink.finish();