1 files changed, 70 insertions, 0 deletions

diff --git a/src/grammar/params.rs b/src/grammar/params.rs
new file mode 100644
index 000000000..be985c80f
--- /dev/null
+++ b/src/grammar/params.rs
@@ -0,0 +1,70 @@
+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, true)
+}
+
+pub(super) fn param_list_opt_types(p: &mut Parser) {
+    list_(p, false)
+}
+
+fn list_(p: &mut Parser, require_types: bool) {
+    assert!(p.at(if require_types { L_PAREN } else { PIPE }));
+    let m = p.start();
+    p.bump();
+    if require_types {
+        self_param(p);
+    }
+    let terminator = if require_types { R_PAREN } else { PIPE };
+    while !p.at(EOF) && !p.at(terminator) {
+        value_parameter(p, require_types);
+        if !p.at(terminator) {
+            p.expect(COMMA);
+        }
+    }
+    p.expect(terminator);
+    m.complete(p, PARAM_LIST);
+}
+
+fn value_parameter(p: &mut Parser, require_type: bool) {
+    let m = p.start();
+    patterns::pattern(p);
+    if p.at(COLON) || require_type {
+        types::ascription(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,
+        (AMPERSAND, SELF_KW, _, _) => 2,
+        (AMPERSAND, MUT_KW, SELF_KW, _) => 3,
+        (AMPERSAND, LIFETIME, SELF_KW, _) => 3,
+        (AMPERSAND, 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);
+    }
+}