organizize

1 files changed, 116 insertions, 0 deletions

diff --git a/crates/libsyntax2/src/grammar/params.rs b/crates/libsyntax2/src/grammar/params.rs
new file mode 100644
index 000000000..32e905cb2
--- /dev/null
+++ b/crates/libsyntax2/src/grammar/params.rs
@@ -0,0 +1,116 @@
+use super::*;
+
+// test param_list
+// fn a() {}
+// fn b(x: i32) {}
+// fn c(x: i32, ) {}
+// fn d(x: i32, y: ()) {}
+pub(super) fn param_list(p: &mut Parser) {
+    list_(p, Flavor::Normal)
+}
+
+// test param_list_opt_patterns
+// fn foo<F: FnMut(&mut Foo<'a>)>(){}
+pub(super) fn param_list_opt_patterns(p: &mut Parser) {
+    list_(p, Flavor::OptionalPattern)
+}
+
+pub(super) fn param_list_opt_types(p: &mut Parser) {
+    list_(p, Flavor::OptionalType)
+}
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+enum Flavor {
+    OptionalType,
+    OptionalPattern,
+    Normal,
+}
+
+impl Flavor {
+    fn type_required(self) -> bool {
+        match self {
+            Flavor::OptionalType => false,
+            _ => true,
+        }
+    }
+}
+
+fn list_(p: &mut Parser, flavor: Flavor) {
+    let (bra, ket) = if flavor.type_required() {
+        (L_PAREN, R_PAREN)
+    } else {
+        (PIPE, PIPE)
+    };
+    assert!(p.at(bra));
+    let m = p.start();
+    p.bump();
+    if flavor.type_required() {
+        self_param(p);
+    }
+    while !p.at(EOF) && !p.at(ket) {
+        value_parameter(p, flavor);
+        if !p.at(ket) {
+            p.expect(COMMA);
+        }
+    }
+    p.expect(ket);
+    m.complete(p, PARAM_LIST);
+}
+
+fn value_parameter(p: &mut Parser, flavor: Flavor) {
+    let m = p.start();
+    match flavor {
+        Flavor::OptionalType | Flavor::Normal => {
+            patterns::pattern(p);
+            if p.at(COLON) || flavor.type_required() {
+                types::ascription(p)
+            }
+        },
+        // test value_parameters_no_patterns
+        // type F = Box<Fn(a: i32, &b: &i32, &mut c: &i32, ())>;
+        Flavor::OptionalPattern => {
+            let la0 = p.current();
+            let la1 = p.nth(1);
+            let la2 = p.nth(2);
+            let la3 = p.nth(3);
+            if la0 == IDENT && la1 == COLON
+                || la0 == AMP && la1 == IDENT && la2 == COLON
+                || la0 == AMP && la1 == MUT_KW && la2 == IDENT && la3 == COLON {
+                patterns::pattern(p);
+                types::ascription(p);
+            } else {
+                types::type_(p);
+            }
+        },
+    }
+    m.complete(p, PARAM);
+}
+
+// test self_param
+// impl S {
+//     fn a(self) {}
+//     fn b(&self,) {}
+//     fn c(&'a self,) {}
+//     fn d(&'a mut self, x: i32) {}
+// }
+fn self_param(p: &mut Parser) {
+    let la1 = p.nth(1);
+    let la2 = p.nth(2);
+    let la3 = p.nth(3);
+    let n_toks = match (p.current(), la1, la2, la3) {
+        (SELF_KW, _, _, _) => 1,
+        (AMP, SELF_KW, _, _) => 2,
+        (AMP, MUT_KW, SELF_KW, _) => 3,
+        (AMP, LIFETIME, SELF_KW, _) => 3,
+        (AMP, LIFETIME, MUT_KW, SELF_KW) => 4,
+        _ => return,
+    };
+    let m = p.start();
+    for _ in 0..n_toks {
+        p.bump();
+    }
+    m.complete(p, SELF_PARAM);
+    if !p.at(R_PAREN) {
+        p.expect(COMMA);
+    }
+}