Merge #4962

4962: Implement APIs for parsing expressions, types, paths, patterns and items r=davidlattimore a=davidlattimore



Co-authored-by: David Lattimore <dml@google.com>

Author: bors[bot]

crates/ra_syntax/src/lib.rs

@@ -168,6 +168,41 @@ impl SourceFile {
     }
 }
 
+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, ra_parser::FragmentKind::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, ra_parser::FragmentKind::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, ra_parser::FragmentKind::Expr)
+    }
+}
+
+impl ast::ModuleItem {
+    /// 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, ra_parser::FragmentKind::Item)
+    }
+}
+
+impl ast::TypeRef {
+    /// 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, ra_parser::FragmentKind::Type)
+    }
+}
+
 /// Matches a `SyntaxNode` against an `ast` type.
 ///
 /// # Example:

crates/ra_syntax/src/parsing.rs

@@ -6,13 +6,14 @@ mod text_token_source;
 mod text_tree_sink;
 mod reparsing;
 
-use crate::{syntax_node::GreenNode, SyntaxError};
+use crate::{syntax_node::GreenNode, AstNode, SyntaxError, SyntaxNode};
 use text_token_source::TextTokenSource;
 use text_tree_sink::TextTreeSink;
 
 pub use lexer::*;
 
 pub(crate) use self::reparsing::incremental_reparse;
+use ra_parser::SyntaxKind;
 
 pub(crate) fn parse_text(text: &str) -> (GreenNode, Vec<SyntaxError>) {
     let (tokens, lexer_errors) = tokenize(&text);
@@ -27,3 +28,32 @@ pub(crate) fn parse_text(text: &str) -> (GreenNode, Vec<SyntaxError>) {
 
     (tree, parser_errors)
 }
+
+/// Returns `text` parsed as a `T` provided there are no parse errors.
+pub(crate) fn parse_text_fragment<T: AstNode>(
+    text: &str,
+    fragment_kind: ra_parser::FragmentKind,
+) -> Result<T, ()> {
+    let (tokens, lexer_errors) = tokenize(&text);
+    if !lexer_errors.is_empty() {
+        return Err(());
+    }
+
+    let mut token_source = TextTokenSource::new(text, &tokens);
+    let mut tree_sink = TextTreeSink::new(text, &tokens);
+
+    // TextTreeSink assumes that there's at least some root node to which it can attach errors and
+    // tokens. We arbitrarily give it a SourceFile.
+    use ra_parser::TreeSink;
+    tree_sink.start_node(SyntaxKind::SOURCE_FILE);
+    ra_parser::parse_fragment(&mut token_source, &mut tree_sink, fragment_kind);
+    tree_sink.finish_node();
+
+    let (tree, parser_errors) = tree_sink.finish();
+    use ra_parser::TokenSource;
+    if !parser_errors.is_empty() || token_source.current().kind != SyntaxKind::EOF {
+        return Err(());
+    }
+
+    SyntaxNode::new_root(tree).first_child().and_then(T::cast).ok_or(())
+}

crates/ra_syntax/src/tests.rs

@@ -54,6 +54,51 @@ fn parser_tests() {
     });
 }
 
+#[test]
+fn expr_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/expr/ok"],
+        &["parser/fragments/expr/err"],
+        crate::ast::Expr::parse,
+    );
+}
+
+#[test]
+fn path_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/path/ok"],
+        &["parser/fragments/path/err"],
+        crate::ast::Path::parse,
+    );
+}
+
+#[test]
+fn pattern_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/pattern/ok"],
+        &["parser/fragments/pattern/err"],
+        crate::ast::Pat::parse,
+    );
+}
+
+#[test]
+fn item_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/item/ok"],
+        &["parser/fragments/item/err"],
+        crate::ast::ModuleItem::parse,
+    );
+}
+
+#[test]
+fn type_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/type/ok"],
+        &["parser/fragments/type/err"],
+        crate::ast::TypeRef::parse,
+    );
+}
+
 #[test]
 fn parser_fuzz_tests() {
     for (_, text) in collect_rust_files(&test_data_dir(), &["parser/fuzz-failures"]) {
@@ -134,3 +179,24 @@ fn dump_tokens_and_errors(tokens: &[Token], errors: &[SyntaxError], text: &str)
     }
     acc
 }
+
+fn fragment_parser_dir_test<T, F>(ok_paths: &[&str], err_paths: &[&str], f: F)
+where
+    T: crate::AstNode,
+    F: Fn(&str) -> Result<T, ()>,
+{
+    dir_tests(&test_data_dir(), ok_paths, "rast", |text, path| {
+        if let Ok(node) = f(text) {
+            format!("{:#?}", crate::ast::AstNode::syntax(&node))
+        } else {
+            panic!("Failed to parse '{:?}'", path);
+        }
+    });
+    dir_tests(&test_data_dir(), err_paths, "rast", |text, path| {
+        if let Ok(_) = f(text) {
+            panic!("'{:?}' successfully parsed when it should have errored", path);
+        } else {
+            "ERROR\n".to_owned()
+        }
+    });
+}

crates/ra_syntax/test_data/parser/fragments/expr/err/0000_truncated_add.rast

@@ -0,0 +1 @@
+ERROR

crates/ra_syntax/test_data/parser/fragments/expr/err/0000_truncated_add.rs

@@ -0,0 +1 @@
+1 +

crates/ra_syntax/test_data/parser/fragments/expr/ok/0000_add.rast

@@ -0,0 +1,8 @@
+BIN_EXPR@0..5
+  LITERAL@0..1
+    INT_NUMBER@0..1 "1"
+  WHITESPACE@1..2 " "
+  PLUS@2..3 "+"
+  WHITESPACE@3..4 " "
+  LITERAL@4..5
+    INT_NUMBER@4..5 "2"

crates/ra_syntax/test_data/parser/fragments/expr/ok/0000_add.rs

@@ -0,0 +1 @@
+1 + 2

crates/ra_syntax/test_data/parser/fragments/item/err/0000_extra_keyword.rast

@@ -0,0 +1 @@
+ERROR

crates/ra_syntax/test_data/parser/fragments/item/err/0000_extra_keyword.rs

@@ -0,0 +1 @@
+fn fn foo() {}

crates/ra_syntax/test_data/parser/fragments/item/ok/0000_fn.rast

@@ -0,0 +1,12 @@
+FN_DEF@0..11
+  FN_KW@0..2 "fn"
+  WHITESPACE@2..3 " "
+  NAME@3..6
+    IDENT@3..6 "foo"
+  PARAM_LIST@6..8
+    L_PAREN@6..7 "("
+    R_PAREN@7..8 ")"
+  WHITESPACE@8..9 " "
+  BLOCK_EXPR@9..11
+    L_CURLY@9..10 "{"
+    R_CURLY@10..11 "}"

crates/ra_syntax/test_data/parser/fragments/item/ok/0000_fn.rs

@@ -0,0 +1 @@
+fn foo() {}

crates/ra_syntax/test_data/parser/fragments/path/err/0000_reserved_word.rast

@@ -0,0 +1 @@
+ERROR

crates/ra_syntax/test_data/parser/fragments/path/err/0000_reserved_word.rs

@@ -0,0 +1 @@
+struct

crates/ra_syntax/test_data/parser/fragments/path/err/0001_expression.rast

@@ -0,0 +1 @@
+ERROR

crates/ra_syntax/test_data/parser/fragments/path/err/0001_expression.rs

@@ -0,0 +1 @@
+a + b

crates/ra_syntax/test_data/parser/fragments/path/ok/0000_single_ident.rast

@@ -0,0 +1,4 @@
+PATH@0..3
+  PATH_SEGMENT@0..3
+    NAME_REF@0..3
+      IDENT@0..3 "foo"

crates/ra_syntax/test_data/parser/fragments/path/ok/0000_single_ident.rs

@@ -0,0 +1 @@
+foo

crates/ra_syntax/test_data/parser/fragments/path/ok/0001_multipart.rast

@@ -0,0 +1,14 @@
+PATH@0..13
+  PATH@0..8
+    PATH@0..3
+      PATH_SEGMENT@0..3
+        NAME_REF@0..3
+          IDENT@0..3 "foo"
+    COLON2@3..5 "::"
+    PATH_SEGMENT@5..8
+      NAME_REF@5..8
+        IDENT@5..8 "bar"
+  COLON2@8..10 "::"
+  PATH_SEGMENT@10..13
+    NAME_REF@10..13
+      IDENT@10..13 "baz"

crates/ra_syntax/test_data/parser/fragments/path/ok/0001_multipart.rs

@@ -0,0 +1 @@
+foo::bar::baz

crates/ra_syntax/test_data/parser/fragments/pattern/err/0000_reserved_word.rast

@@ -0,0 +1 @@
+ERROR

crates/ra_syntax/test_data/parser/fragments/pattern/err/0000_reserved_word.rs

@@ -0,0 +1 @@
+fn

crates/ra_syntax/test_data/parser/fragments/pattern/err/0001_missing_paren.rast

@@ -0,0 +1 @@
+ERROR

crates/ra_syntax/test_data/parser/fragments/pattern/err/0001_missing_paren.rs

@@ -0,0 +1 @@
+Some(x

crates/ra_syntax/test_data/parser/fragments/pattern/ok/0000_enum.rast

@@ -0,0 +1,10 @@
+TUPLE_STRUCT_PAT@0..7
+  PATH@0..4
+    PATH_SEGMENT@0..4
+      NAME_REF@0..4
+        IDENT@0..4 "Some"
+  L_PAREN@4..5 "("
+  BIND_PAT@5..6
+    NAME@5..6
+      IDENT@5..6 "x"
+  R_PAREN@6..7 ")"

crates/ra_syntax/test_data/parser/fragments/pattern/ok/0000_enum.rs

@@ -0,0 +1 @@
+Some(x)

crates/ra_syntax/test_data/parser/fragments/type/err/0000_missing_close.rast

@@ -0,0 +1 @@
+ERROR

crates/ra_syntax/test_data/parser/fragments/type/err/0000_missing_close.rs

@@ -0,0 +1 @@
+Result<Foo, Bar

crates/ra_syntax/test_data/parser/fragments/type/ok/0000_result.rast

@@ -0,0 +1,22 @@
+PATH_TYPE@0..16
+  PATH@0..16
+    PATH_SEGMENT@0..16
+      NAME_REF@0..6
+        IDENT@0..6 "Result"
+      TYPE_ARG_LIST@6..16
+        L_ANGLE@6..7 "<"
+        TYPE_ARG@7..10
+          PATH_TYPE@7..10
+            PATH@7..10
+              PATH_SEGMENT@7..10
+                NAME_REF@7..10
+                  IDENT@7..10 "Foo"
+        COMMA@10..11 ","
+        WHITESPACE@11..12 " "
+        TYPE_ARG@12..15
+          PATH_TYPE@12..15
+            PATH@12..15
+              PATH_SEGMENT@12..15
+                NAME_REF@12..15
+                  IDENT@12..15 "Bar"
+        R_ANGLE@15..16 ">"

crates/ra_syntax/test_data/parser/fragments/type/ok/0000_result.rs

@@ -0,0 +1 @@
+Result<Foo, Bar>