fixing empty catch clauses ... Issue #470

lib/grammar.js

@@ -332,8 +332,6 @@
     Catch: [
       o("CATCH Identifier Block", function() {
         return [$2, $3];
-      }), o("CATCH Identifier TERMINATOR", function() {
-        return [$2, new Expressions()];
       })
     ],
     Throw: [

lib/rewriter.js

@@ -196,17 +196,23 @@
     Rewriter.prototype.addImplicitIndentation = function() {
       return this.scanTokens((function(__this) {
         var __func = function(prev, token, post, i) {
-          var idx, indent, insertion, outdent, parens, pre, starter, tok;
+          var _c, idx, indent, insertion, outdent, parens, pre, starter, tok;
           if (token[0] === 'ELSE' && prev[0] !== 'OUTDENT') {
-            this.tokens.splice(i, 0, ['INDENT', 2, token[2]], ['OUTDENT', 2, token[2]]);
+            this.tokens.splice.apply(this.tokens, [i, 0].concat(this.indentation(token)));
             return 2;
           }
+          if (token[0] === 'CATCH' && this.tokens[i + 2][0] === 'TERMINATOR') {
+            this.tokens.splice.apply(this.tokens, [i + 2, 0].concat(this.indentation(token)));
+            return 4;
+          }
           if (!(include(SINGLE_LINERS, token[0]) && post[0] !== 'INDENT' && !(token[0] === 'ELSE' && post[0] === 'IF'))) {
             return 1;
           }
           starter = token[0];
-          indent = ['INDENT', 2, token[2]];
-          indent.generated = true;
+          _c = this.indentation(token);
+          indent = _c[0];
+          outdent = _c[1];
+          indent.generated = (outdent.generated = true);
           this.tokens.splice(i + 1, 0, indent);
           idx = i + 1;
           parens = 0;
@@ -216,8 +222,6 @@
             pre = this.tokens[idx - 1];
             if ((!tok || (include(SINGLE_CLOSERS, tok[0]) && tok[1] !== ';' && parens === 0) || (tok[0] === ')' && parens === 0)) && !(tok[0] === 'ELSE' && !('IF' === starter || 'THEN' === starter))) {
               insertion = pre[0] === "," ? idx - 1 : idx;
-              outdent = ['OUTDENT', 2, token[2]];
-              outdent.generated = true;
               this.tokens.splice(insertion, 0, outdent);
               break;
             }
@@ -334,6 +338,9 @@
         });
       })(this));
     };
+    Rewriter.prototype.indentation = function(token) {
+      return [['INDENT', 2, token[2]], ['OUTDENT', 2, token[2]]];
+    };
     return Rewriter;
   })();
   BALANCED_PAIRS = [['(', ')'], ['[', ']'], ['{', '}'], ['INDENT', 'OUTDENT'], ['PARAM_START', 'PARAM_END'], ['CALL_START', 'CALL_END'], ['INDEX_START', 'INDEX_END']];

src/grammar.coffee

@@ -378,7 +378,6 @@ grammar: {
   # A catch clause names its error and runs a block of code.
   Catch: [
     o "CATCH Identifier Block",                 -> [$2, $3]
-    o "CATCH Identifier TERMINATOR",            -> [$2, new Expressions]
   ]
 
   # Throw an exception object.

src/rewriter.coffee

@@ -48,7 +48,7 @@ exports.Rewriter: class Rewriter
       move: block @tokens[i - 1], @tokens[i], @tokens[i + 1], i
       i: + move
     true
-    
+
   # Massage newlines and indentations so that comments don't have to be
   # correctly indented, or appear on a line of their own.
   adjustComments: ->
@@ -159,14 +159,17 @@ exports.Rewriter: class Rewriter
   addImplicitIndentation: ->
     @scanTokens (prev, token, post, i) =>
       if token[0] is 'ELSE' and prev[0] isnt 'OUTDENT'
-        @tokens.splice i, 0, ['INDENT', 2, token[2]], ['OUTDENT', 2, token[2]]
+        @tokens.splice i, 0, @indentation(token)...
         return 2
+      if token[0] is 'CATCH' and @tokens[i + 2][0] is 'TERMINATOR'
+        @tokens.splice i + 2, 0, @indentation(token)...
+        return 4
       return 1 unless include(SINGLE_LINERS, token[0]) and
         post[0] isnt 'INDENT' and
         not (token[0] is 'ELSE' and post[0] is 'IF')
       starter: token[0]
-      indent: ['INDENT', 2, token[2]]
-      indent.generated: true
+      [indent, outdent]: @indentation token
+      indent.generated: outdent.generated: true
       @tokens.splice i + 1, 0, indent
       idx: i + 1
       parens: 0
@@ -179,8 +182,6 @@ exports.Rewriter: class Rewriter
             (tok[0] is ')' and parens is 0)) and
             not (tok[0] is 'ELSE' and starter not in ['IF', 'THEN'])
           insertion: if pre[0] is "," then idx - 1 else idx
-          outdent: ['OUTDENT', 2, token[2]]
-          outdent.generated: true
           @tokens.splice insertion, 0, outdent
           break
         parens: + 1 if tok[0] is '('
@@ -257,6 +258,10 @@ exports.Rewriter: class Rewriter
       else
         return 1
 
+  # Generate the indentation tokens, based on another token on the same line.
+  indentation: (token) ->
+    [['INDENT', 2, token[2]], ['OUTDENT', 2, token[2]]]
+
 # Constants
 # ---------
 

test/test_try_catch.coffee

@@ -28,4 +28,11 @@ ok result is 5
 try
   # nothing
 catch err
-  #nothing
+  # nothing
+
+try
+  # nothing
+finally
+  # nothing
+
+ok yes