From d4366940976a3d150a8b5bf92dc24f0162d4d62c Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Mon, 30 Jul 2018 17:02:51 +0300
Subject: Path expressions

---
 src/parser/grammar/expressions.rs | 27 ++++++++++++++++++++++++++-
 src/parser/grammar/mod.rs         |  1 +
 src/parser/grammar/paths.rs       | 32 +++++++++++++++++++++++++-------
 src/parser/grammar/type_args.rs   | 26 ++++++++++++++++++++++++++
 4 files changed, 78 insertions(+), 8 deletions(-)
 create mode 100644 src/parser/grammar/type_args.rs

(limited to 'src/parser/grammar')

diff --git a/src/parser/grammar/expressions.rs b/src/parser/grammar/expressions.rs
index 40f41535e..ece698248 100644
--- a/src/parser/grammar/expressions.rs
+++ b/src/parser/grammar/expressions.rs
@@ -2,7 +2,16 @@ use super::*;
 
 // test expr_literals
 // fn foo() {
-//     let _ = 92;
+//     let _ = true;
+//     let _ = false;
+//     let _ = 1;
+//     let _ = 2.0;
+//     let _ = b'a';
+//     let _ = 'b';
+//     let _ = "c";
+//     let _ = r"d";
+//     let _ = b"e";
+//     let _ = br"f";
 // }
 pub(super) fn literal(p: &mut Parser) -> bool {
     match p.current() {
@@ -21,6 +30,9 @@ pub(super) fn expr(p: &mut Parser) {
     if literal(p) {
         return;
     }
+    if paths::is_path_start(p) {
+        return path_expr(p);
+    }
 
     match p.current() {
         L_PAREN => tuple_expr(p),
@@ -35,3 +47,16 @@ fn tuple_expr(p: &mut Parser) {
     p.expect(R_PAREN);
     m.complete(p, TUPLE_EXPR);
 }
+
+// test path_expr
+// fn foo() {
+//     let _ = a;
+//     let _ = a::b;
+//     let _ = ::a::<b>;
+// }
+fn path_expr(p: &mut Parser) {
+    assert!(paths::is_path_start(p));
+    let m = p.start();
+    paths::expr_path(p);
+    m.complete(p, PATH_EXPR);
+}
diff --git a/src/parser/grammar/mod.rs b/src/parser/grammar/mod.rs
index e24f1055e..e4823eadb 100644
--- a/src/parser/grammar/mod.rs
+++ b/src/parser/grammar/mod.rs
@@ -27,6 +27,7 @@ mod items;
 mod paths;
 mod patterns;
 mod type_params;
+mod type_args;
 mod types;
 
 use {
diff --git a/src/parser/grammar/paths.rs b/src/parser/grammar/paths.rs
index d3eb20ea1..69ed84665 100644
--- a/src/parser/grammar/paths.rs
+++ b/src/parser/grammar/paths.rs
@@ -8,19 +8,26 @@ pub(super) fn is_path_start(p: &Parser) -> bool {
 }
 
 pub(super) fn use_path(p: &mut Parser) {
-    path(p)
+    path(p, Mode::Use)
 }
 
 pub(super) fn type_path(p: &mut Parser) {
-    path(p)
+    path(p, Mode::Type)
 }
 
-fn path(p: &mut Parser) {
+pub(super) fn expr_path(p: &mut Parser) {
+    path(p, Mode::Expr)
+}
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+enum Mode { Use, Type, Expr }
+
+fn path(p: &mut Parser, mode: Mode) {
     if !is_path_start(p) {
         return;
     }
     let path = p.start();
-    path_segment(p, true);
+    path_segment(p, mode, true);
     let mut qual = path.complete(p, PATH);
     loop {
         let use_tree = match p.nth(1) {
@@ -30,7 +37,7 @@ fn path(p: &mut Parser) {
         if p.at(COLONCOLON) && !use_tree {
             let path = qual.precede(p);
             p.bump();
-            path_segment(p, false);
+            path_segment(p, mode, false);
             let path = path.complete(p, PATH);
             qual = path;
         } else {
@@ -39,13 +46,16 @@ fn path(p: &mut Parser) {
     }
 }
 
-fn path_segment(p: &mut Parser, first: bool) {
+fn path_segment(p: &mut Parser, mode: Mode, first: bool) {
     let segment = p.start();
     if first {
         p.eat(COLONCOLON);
     }
     match p.current() {
-        IDENT => name_ref(p),
+        IDENT => {
+            name_ref(p);
+            path_generic_args(p, mode);
+        },
         SELF_KW | SUPER_KW => p.bump(),
         _ => {
             p.error("expected identifier");
@@ -53,3 +63,11 @@ fn path_segment(p: &mut Parser, first: bool) {
     };
     segment.complete(p, PATH_SEGMENT);
 }
+
+fn path_generic_args(p: &mut Parser, mode: Mode) {
+    match mode {
+        Mode::Use => return,
+        Mode::Type => type_args::list(p, false),
+        Mode::Expr => type_args::list(p, true),
+    }
+}
diff --git a/src/parser/grammar/type_args.rs b/src/parser/grammar/type_args.rs
new file mode 100644
index 000000000..20e75b4b0
--- /dev/null
+++ b/src/parser/grammar/type_args.rs
@@ -0,0 +1,26 @@
+use super::*;
+
+pub(super) fn list(p: &mut Parser, colon_colon_required: bool) {
+    let m;
+    match (colon_colon_required, p.nth(0), p.nth(1)) {
+        (_, COLONCOLON, L_ANGLE) => {
+            m = p.start();
+            p.bump();
+            p.bump();
+        }
+        (false, L_ANGLE, _) => {
+            m = p.start();
+            p.bump();
+        }
+        _ => return
+    };
+
+    while !p.at(EOF) && !p.at(R_ANGLE) {
+        types::type_(p);
+        if !p.at(R_ANGLE) && !p.expect(COMMA) {
+            break;
+        }
+    }
+    p.expect(R_ANGLE);
+    m.complete(p, TYPE_ARG_LIST);
+}
-- 
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