fix: Surround operators with parens when pretty-printing

Fixes #60
gluon-lang · Sep 9, 2016 · 7ccc6f2 · 7ccc6f2
1 parent b112c45
commit 7ccc6f2
Show file tree

Hide file tree

Showing 4 changed files with 22 additions and 8 deletions.
diff --git a/base/src/ast.rs b/base/src/ast.rs
@@ -370,3 +370,7 @@ fn get_return_type(env: &TypeEnv, alias_type: &ArcType, arg_count: usize) -> Arc
         }
     }
 }
+
+pub fn is_operator_char(c: char) -> bool {
+    "+-*/&|=<>".chars().any(|x| x == c)
+}
diff --git a/base/src/types.rs b/base/src/types.rs
@@ -7,7 +7,7 @@ use std::marker::PhantomData;
 
 use pretty::{DocAllocator, Arena, DocBuilder};
 
-use ast::DisplayEnv;
+use ast::{DisplayEnv, is_operator_char};
 use symbol::{Symbol, SymbolRef};
 
 /// Trait for values which contains kinded values which can be refered by name
@@ -800,6 +800,14 @@ impl<'a, I, T, E> DisplayType<'a, I, T, E>
     fn pretty(&self, arena: &'a Arena<'a>) -> DocBuilder<'a, Arena<'a>>
         where I: AsRef<str>,
     {
+        fn ident<'b>(arena: &'b Arena<'b>, name: &'b str) -> DocBuilder<'b, Arena<'b>> {
+            if name.starts_with(is_operator_char) {
+                chain![arena; "(", name, ")"]
+            } else {
+                arena.text(name)
+            }
+        }
+
         let p = self.prec;
         match *self.typ {
             Type::Hole => arena.text("_"),
@@ -913,7 +921,7 @@ impl<'a, I, T, E> DisplayType<'a, I, T, E>
                             _ => rhs = rhs.nest(4),
                         }
                         let f = chain![arena;
-                            self.env.string(&field.name),
+                            ident(arena, self.env.string(&field.name)),
                             " : ",
                             rhs.group(),
                             if i + 1 != fields.len() {

diff --git a/base/tests/types.rs b/base/tests/types.rs
@@ -66,6 +66,10 @@ fn some_record() -> ArcType<&'static str> {
                       Field {
                           name: "test",
                           typ: test.clone(),
+                      },
+                      Field {
+                          name: "+",
+                          typ: Type::function(vec![Type::int(), Type::int()], Type::int()),
                       }])
 }
 
@@ -97,7 +101,7 @@ fn show_record() {
                                 }]);
     assert_eq_display!(format!("{}", typ), "{ Test a = a -> String, x : Int }");
     assert_eq_display!(format!("{}", some_record()),
-                       "{ Test a = a -> String, x : Int, test : Test a }");
+                       "{ Test a = a -> String, x : Int, test : Test a, (+) : Int -> Int -> Int }");
     let typ = Type::record(vec![Field {
                                     name: "Test",
                                     typ: Alias::new("Test",
@@ -159,7 +163,8 @@ fn show_record_multi_line() {
     record_looooooooooooooooooooooooooooooooooong : {
         Test a = a -> String,
         x : Int,
-        test : Test a
+        test : Test a,
+        (+) : Int -> Int -> Int
     },
     looooooooooooooooooooooooooooooooooong_field : Test a
 }"#;

diff --git a/parser/src/lexer.rs b/parser/src/lexer.rs
@@ -1,6 +1,7 @@
 use std::cmp::Ordering;
 use std::fmt;
 
+use base::ast::is_operator_char;
 use base::pos::{BytePos, CharPos, Location, Span, Spanned};
 
 use combine::primitives::{Consumed, Error as CombineError, RangeStream};
@@ -303,10 +304,6 @@ impl Contexts {
     }
 }
 
-fn is_operator_char(c: char) -> bool {
-    "+-*/&|=<>".chars().any(|x| x == c)
-}
-
 pub struct Lexer<'input, I>
     where I: RangeStream<Item = char, Range = &'input str>,
 {