Handle empty default value during variable expansion (#1)

* Handle empty default value during variable expansion * Make expression after colon optional As suggested by @maxbrunsfeld
Wilfred · Feb 24, 2018 · 741cfce · 741cfce
1 parent bda6939
commit 741cfce
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Showing 4 changed files with 9,387 additions and 8,962 deletions.
diff --git a/corpus/expressions.txt b/corpus/expressions.txt
@@ -28,12 +28,17 @@ Variable expansions
 
 echo ${abc}
 echo ${abc:-def}
+echo ${abc:- }
+echo ${abc:
+}
 
 ---
 
 (program
   (command (command_name (word)) (expansion (variable_name)))
-  (command (command_name (word)) (expansion (variable_name) (word))))
+  (command (command_name (word)) (expansion (variable_name) (word)))
+  (command (command_name (word)) (expansion (variable_name)))
+  (command (command_name (word)) (expansion (variable_name))))
 
 ===================================
 Other variable expansion operators

diff --git a/grammar.js b/grammar.js
@@ -295,7 +295,7 @@ module.exports = grammar({
         seq(
           $._variable_name,
           choice(':', ':?', '=', ':-', '%', '/'),
-          $._expression
+          optional($._expression)
         )
       ),
       '}'

diff --git a/src/grammar.json b/src/grammar.json
@@ -1084,8 +1084,16 @@
                   ]
                 },
                 {
-                  "type": "SYMBOL",
-                  "name": "_expression"
+                  "type": "CHOICE",
+                  "members": [
+                    {
+                      "type": "SYMBOL",
+                      "name": "_expression"
+                    },
+                    {
+                      "type": "BLANK"
+                    }
+                  ]
                 }
               ]
             }