1 files changed, 141 insertions, 0 deletions

diff --git a/src/grammar/mod.rs b/src/grammar/mod.rs
new file mode 100644
index 000000000..b558da477
--- /dev/null
+++ b/src/grammar/mod.rs
@@ -0,0 +1,141 @@
+//! This is the actual "grammar" of the Rust language.
+//!
+//! Each function in this module and its children corresponds
+//! to a production of the format grammar. Submodules roughly
+//! correspond to different *areas* of the grammar. By convention,
+//! each submodule starts with `use super::*` import and exports
+//! "public" productions via `pub(super)`.
+//!
+//! See docs for `Parser` to learn about API, available to the grammar,
+//! and see docs for `Event` to learn how this actually manages to
+//! produce parse trees.
+//!
+//! Code in this module also contains inline tests, which start with
+//! `// test name-of-the-test` comment and look like this:
+//!
+//! ```
+//! // test fn_item_with_zero_parameters
+//! // fn foo() {}
+//! ```
+//!
+//! After adding a new inline-test, run `cargo collect-tests` to extract
+//! it as a standalone text-fixture into `tests/data/parser/inline`, and
+//! run `cargo test` once to create the "gold" value.
+mod attributes;
+mod expressions;
+mod items;
+mod params;
+mod paths;
+mod patterns;
+mod type_args;
+mod type_params;
+mod types;
+
+use {
+    parser_api::{CompletedMarker, Parser, TokenSet},
+    SyntaxKind::{self, *},
+};
+
+pub(crate) fn file(p: &mut Parser) {
+    let file = p.start();
+    p.eat(SHEBANG);
+    items::mod_contents(p, false);
+    file.complete(p, FILE);
+}
+
+fn visibility(p: &mut Parser) {
+    if p.at(PUB_KW) {
+        let vis = p.start();
+        p.bump();
+        if p.at(L_PAREN) {
+            match p.nth(1) {
+                // test crate_visibility
+                // pub(crate) struct S;
+                // pub(self) struct S;
+                // pub(self) struct S;
+                // pub(self) struct S;
+                CRATE_KW | SELF_KW | SUPER_KW => {
+                    p.bump();
+                    p.bump();
+                    p.expect(R_PAREN);
+                }
+                IN_KW => {
+                    p.bump();
+                    p.bump();
+                    paths::use_path(p);
+                    p.expect(R_PAREN);
+                }
+                _ => (),
+            }
+        }
+        vis.complete(p, VISIBILITY);
+    }
+}
+
+fn alias(p: &mut Parser) -> bool {
+    if p.at(AS_KW) {
+        let alias = p.start();
+        p.bump();
+        name(p);
+        alias.complete(p, ALIAS);
+    }
+    true //FIXME: return false if three are errors
+}
+
+fn abi(p: &mut Parser) {
+    assert!(p.at(EXTERN_KW));
+    let abi = p.start();
+    p.bump();
+    match p.current() {
+        STRING | RAW_STRING => p.bump(),
+        _ => (),
+    }
+    abi.complete(p, ABI);
+}
+
+fn fn_ret_type(p: &mut Parser) -> bool {
+    if p.at(THIN_ARROW) {
+        p.bump();
+        types::type_(p);
+        true
+    } else {
+        false
+    }
+}
+
+fn name(p: &mut Parser) {
+    if p.at(IDENT) {
+        let m = p.start();
+        p.bump();
+        m.complete(p, NAME);
+    } else {
+        p.error("expected a name");
+    }
+}
+
+fn name_ref(p: &mut Parser) {
+    if p.at(IDENT) {
+        let m = p.start();
+        p.bump();
+        m.complete(p, NAME_REF);
+    } else {
+        p.error("expected identifier");
+    }
+}
+
+fn error_block(p: &mut Parser, message: &str) {
+    assert!(p.at(L_CURLY));
+    let err = p.start();
+    p.error(message);
+    p.bump();
+    let mut level: u32 = 1;
+    while level > 0 && !p.at(EOF) {
+        match p.current() {
+            L_CURLY => level += 1,
+            R_CURLY => level -= 1,
+            _ => (),
+        }
+        p.bump();
+    }
+    err.complete(p, ERROR);
+}