[#46] Restrict prefix application to operators (#47)

Author: jonhue

grammar.js

@@ -225,7 +225,7 @@ module.exports = grammar({
       ')'
     )),
     prefix_application: $ => prec.right(PREC.PREFIX, seq(
-      field('abstraction', $.identifier),
+      field('abstraction', alias($._operator, $.identifier)),
       field('argument', $._simple_expression)
     )),
     infix_application: $ => choice(

test/corpus/expressions.txt

@@ -113,7 +113,6 @@ a(1)(1)
 +(1)
 a(?, 1)
 + 1
-a 1
 1 `a` -b(1)
 
 ---
@@ -128,11 +127,9 @@ a 1
   arguments: (arguments
       (argument
         value: (number))))
-  (application
+  (prefix_application
     abstraction: (identifier)
-  arguments: (arguments
-      (argument
-        value: (number))))
+    argument: (number))
   (application
     abstraction: (identifier)
     arguments: (arguments
@@ -142,9 +139,6 @@ a 1
   (prefix_application
     abstraction: (identifier)
     argument: (number))
-  (prefix_application
-    abstraction: (identifier)
-    argument: (number))
   (infix_application
     left: (number)
     abstraction: (infix_application_operator)