5 files changed, 417 insertions, 0 deletions

diff --git a/src/parser/grammar/items/consts.rs b/src/parser/grammar/items/consts.rs
new file mode 100644
index 000000000..c9881d681
--- /dev/null
+++ b/src/parser/grammar/items/consts.rs
@@ -0,0 +1,21 @@
+use super::*;
+
+pub(super) fn static_item(p: &mut Parser) {
+    const_or_static(p, STATIC_KW)
+}
+
+pub(super) fn const_item(p: &mut Parser) {
+    const_or_static(p, CONST_KW)
+}
+
+fn const_or_static(p: &mut Parser, kw: SyntaxKind) {
+    assert!(p.at(kw));
+    p.bump();
+    p.eat(MUT_KW); // TODO: validator to forbid const mut
+    p.expect(IDENT);
+    p.expect(COLON);
+    types::type_ref(p);
+    p.expect(EQ);
+    expressions::expr(p);
+    p.expect(SEMI);
+}
diff --git a/src/parser/grammar/items/mod.rs b/src/parser/grammar/items/mod.rs
new file mode 100644
index 000000000..3612802e1
--- /dev/null
+++ b/src/parser/grammar/items/mod.rs
@@ -0,0 +1,196 @@
+use super::*;
+
+mod structs;
+mod use_item;
+mod consts;
+mod traits;
+
+pub(super) fn mod_contents(p: &mut Parser, stop_on_r_curly: bool) {
+    attributes::inner_attributes(p);
+    while !p.at(EOF) && !(stop_on_r_curly && p.at(R_CURLY)) {
+        item(p);
+    }
+}
+
+pub(super) const ITEM_FIRST: TokenSet = token_set![
+    EXTERN_KW, MOD_KW, USE_KW, STRUCT_KW, ENUM_KW, FN_KW, PUB_KW, POUND
+];
+
+fn item(p: &mut Parser) {
+    let item = p.start();
+    attributes::outer_attributes(p);
+    visibility(p);
+    let la = p.nth(1);
+    let item_kind = match p.current() {
+        USE_KW => {
+            use_item::use_item(p);
+            USE_ITEM
+        }
+        // test extern_crate
+        // extern crate foo;
+        EXTERN_KW if la == CRATE_KW => {
+            extern_crate_item(p);
+            EXTERN_CRATE_ITEM
+        }
+        EXTERN_KW => {
+            abi(p);
+            match p.current() {
+                // test extern_fn
+                // extern fn foo() {}
+                FN_KW => {
+                    fn_item(p);
+                    FN_ITEM
+                }
+                // test extern_block
+                // extern {}
+                L_CURLY => {
+                    extern_block(p);
+                    EXTERN_BLOCK
+                }
+                // test extern_struct
+                // extern struct Foo;
+                _ => {
+                    item.abandon(p);
+                    p.error().message("expected `fn` or `{`").emit();
+                    return;
+                }
+            }
+        }
+        STATIC_KW => {
+            consts::static_item(p);
+            STATIC_ITEM
+        }
+        CONST_KW => match p.nth(1) {
+            // test const_fn
+            // const fn foo() {}
+            FN_KW => {
+                p.bump();
+                fn_item(p);
+                FN_ITEM
+            }
+            // test const_unsafe_fn
+            // const unsafe fn foo() {}
+            UNSAFE_KW if p.nth(2) == FN_KW => {
+                p.bump();
+                p.bump();
+                fn_item(p);
+                FN_ITEM
+            }
+            _ => {
+                consts::const_item(p);
+                CONST_ITEM
+            }
+        },
+        // TODO: auto trait
+        // test unsafe_trait
+        // unsafe trait T {}
+        UNSAFE_KW if la == TRAIT_KW => {
+            p.bump();
+            traits::trait_item(p);
+            TRAIT_ITEM
+        }
+        // TODO: default impl
+        // test unsafe_impl
+        // unsafe impl Foo {}
+        UNSAFE_KW if la == IMPL_KW => {
+            p.bump();
+            traits::impl_item(p);
+            IMPL_ITEM
+        }
+        MOD_KW => {
+            mod_item(p);
+            MOD_ITEM
+        }
+        STRUCT_KW => {
+            structs::struct_item(p);
+            STRUCT_ITEM
+        }
+        ENUM_KW => {
+            structs::enum_item(p);
+            ENUM_ITEM
+        }
+        FN_KW => {
+            fn_item(p);
+            FN_ITEM
+        }
+        L_CURLY => {
+            item.abandon(p);
+            error_block(p, "expected item");
+            return;
+        }
+        err_token => {
+            item.abandon(p);
+            let message = if err_token == SEMI {
+                //TODO: if the item is incomplete, this message is misleading
+                "expected item, found `;`\n\
+                 consider removing this semicolon"
+            } else {
+                "expected item"
+            };
+            p.err_and_bump(message);
+            return;
+        }
+    };
+    item.complete(p, item_kind);
+}
+
+fn extern_crate_item(p: &mut Parser) {
+    assert!(p.at(EXTERN_KW));
+    p.bump();
+    assert!(p.at(CRATE_KW));
+    p.bump();
+
+    p.expect(IDENT) && alias(p) && p.expect(SEMI);
+}
+
+fn extern_block(p: &mut Parser) {
+    assert!(p.at(L_CURLY));
+    p.bump();
+    p.expect(R_CURLY);
+}
+
+fn mod_item(p: &mut Parser) {
+    assert!(p.at(MOD_KW));
+    p.bump();
+
+    if p.expect(IDENT) && !p.eat(SEMI) {
+        if p.expect(L_CURLY) {
+            mod_contents(p, true);
+            p.expect(R_CURLY);
+        }
+    }
+}
+
+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_item(p: &mut Parser) {
+    assert!(p.at(FN_KW));
+    p.bump();
+
+    p.expect(IDENT);
+    if p.at(L_PAREN) {
+        fn_value_parameters(p);
+    } else {
+        p.error().message("expected function arguments").emit();
+    }
+
+    if p.at(L_CURLY) {
+        p.expect(L_CURLY);
+        p.expect(R_CURLY);
+    }
+
+    fn fn_value_parameters(p: &mut Parser) {
+        assert!(p.at(L_PAREN));
+        p.bump();
+        p.expect(R_PAREN);
+    }
+}
diff --git a/src/parser/grammar/items/structs.rs b/src/parser/grammar/items/structs.rs
new file mode 100644
index 000000000..69d95c698
--- /dev/null
+++ b/src/parser/grammar/items/structs.rs
@@ -0,0 +1,117 @@
+use super::*;
+
+pub(super) fn struct_item(p: &mut Parser) {
+    assert!(p.at(STRUCT_KW));
+    p.bump();
+
+    if !p.expect(IDENT) {
+        return;
+    }
+    type_params::list(p);
+    match p.current() {
+        WHERE_KW => {
+            type_params::where_clause(p);
+            match p.current() {
+                SEMI => {
+                    p.bump();
+                    return;
+                }
+                L_CURLY => named_fields(p),
+                _ => {
+                    //TODO: special case `(` error message
+                    p.error().message("expected `;` or `{`").emit();
+                    return;
+                }
+            }
+        }
+        SEMI => {
+            p.bump();
+            return;
+        }
+        L_CURLY => named_fields(p),
+        L_PAREN => {
+            pos_fields(p);
+            p.expect(SEMI);
+        }
+        _ => {
+            p.error().message("expected `;`, `{`, or `(`").emit();
+            return;
+        }
+    }
+}
+
+pub(super) fn enum_item(p: &mut Parser) {
+    assert!(p.at(ENUM_KW));
+    p.bump();
+    p.expect(IDENT);
+    type_params::list(p);
+    type_params::where_clause(p);
+    if p.expect(L_CURLY) {
+        while !p.at(EOF) && !p.at(R_CURLY) {
+            let var = p.start();
+            attributes::outer_attributes(p);
+            if p.at(IDENT) {
+                p.bump();
+                match p.current() {
+                    L_CURLY => named_fields(p),
+                    L_PAREN => pos_fields(p),
+                    EQ => {
+                        p.bump();
+                        expressions::expr(p);
+                    }
+                    _ => (),
+                }
+                var.complete(p, ENUM_VARIANT);
+            } else {
+                var.abandon(p);
+                p.err_and_bump("expected enum variant");
+            }
+            if !p.at(R_CURLY) {
+                p.expect(COMMA);
+            }
+        }
+        p.expect(R_CURLY);
+    }
+}
+
+fn named_fields(p: &mut Parser) {
+    assert!(p.at(L_CURLY));
+    p.bump();
+    while !p.at(R_CURLY) && !p.at(EOF) {
+        named_field(p);
+        if !p.at(R_CURLY) {
+            p.expect(COMMA);
+        }
+    }
+    p.expect(R_CURLY);
+
+    fn named_field(p: &mut Parser) {
+        let field = p.start();
+        visibility(p);
+        if p.expect(IDENT) {
+            p.expect(COLON);
+            types::type_ref(p);
+            field.complete(p, NAMED_FIELD);
+        } else {
+            field.abandon(p);
+            p.err_and_bump("expected field declaration");
+        }
+    }
+}
+
+fn pos_fields(p: &mut Parser) {
+    if !p.expect(L_PAREN) {
+        return;
+    }
+    while !p.at(R_PAREN) && !p.at(EOF) {
+        let pos_field = p.start();
+        visibility(p);
+        types::type_ref(p);
+        pos_field.complete(p, POS_FIELD);
+
+        if !p.at(R_PAREN) {
+            p.expect(COMMA);
+        }
+    }
+    p.expect(R_PAREN);
+}
diff --git a/src/parser/grammar/items/traits.rs b/src/parser/grammar/items/traits.rs
new file mode 100644
index 000000000..3bef9639f
--- /dev/null
+++ b/src/parser/grammar/items/traits.rs
@@ -0,0 +1,17 @@
+use super::*;
+
+pub(super) fn trait_item(p: &mut Parser) {
+    assert!(p.at(TRAIT_KW));
+    p.bump();
+    p.expect(IDENT);
+    p.expect(L_CURLY);
+    p.expect(R_CURLY);
+}
+
+pub(super) fn impl_item(p: &mut Parser) {
+    assert!(p.at(IMPL_KW));
+    p.bump();
+    p.expect(IDENT);
+    p.expect(L_CURLY);
+    p.expect(R_CURLY);
+}
diff --git a/src/parser/grammar/items/use_item.rs b/src/parser/grammar/items/use_item.rs
new file mode 100644
index 000000000..38e7b3f8a
--- /dev/null
+++ b/src/parser/grammar/items/use_item.rs
@@ -0,0 +1,66 @@
+use super::*;
+
+pub(super) fn use_item(p: &mut Parser) {
+    assert!(p.at(USE_KW));
+    p.bump();
+    use_tree(p);
+    p.expect(SEMI);
+}
+
+fn use_tree(p: &mut Parser) {
+    let la = p.nth(1);
+    let m = p.start();
+    match (p.current(), la) {
+        (STAR, _) => p.bump(),
+        (COLONCOLON, STAR) => {
+            p.bump();
+            p.bump();
+        }
+        (L_CURLY, _) | (COLONCOLON, L_CURLY) => {
+            if p.at(COLONCOLON) {
+                p.bump();
+            }
+            nested_trees(p);
+        }
+        _ if paths::is_path_start(p) => {
+            paths::use_path(p);
+            match p.current() {
+                AS_KW => {
+                    alias(p);
+                }
+                COLONCOLON => {
+                    p.bump();
+                    match p.current() {
+                        STAR => {
+                            p.bump();
+                        }
+                        L_CURLY => nested_trees(p),
+                        _ => {
+                            // is this unreachable?
+                            p.error().message("expected `{` or `*`").emit();
+                        }
+                    }
+                }
+                _ => (),
+            }
+        }
+        _ => {
+            m.abandon(p);
+            p.err_and_bump("expected one of `*`, `::`, `{`, `self`, `super`, `indent`");
+            return;
+        }
+    }
+    m.complete(p, USE_TREE);
+}
+
+fn nested_trees(p: &mut Parser) {
+    assert!(p.at(L_CURLY));
+    p.bump();
+    while !p.at(EOF) && !p.at(R_CURLY) {
+        use_tree(p);
+        if !p.at(R_CURLY) {
+            p.expect(COMMA);
+        }
+    }
+    p.expect(R_CURLY);
+}