From 3447059f1145550465ecbe10c5d6e82420d5a823 Mon Sep 17 00:00:00 2001
From: Brian Donovan <me@brian-donovan.com>
Date: Thu, 29 Dec 2016 14:45:30 -0800
Subject: [PATCH] refactor: introduce a `Loop` node type (#105)

BREAKING CHANGE: Rather than a `While` node with a virtual condition
and null for other properties, this introduces a new `Loop` node that
only has a body.
---
 src/parser.js                  | 19 +++++++++-----
 test/examples/loop/output.json | 48 ++++++++++++++++++++--------------
 2 files changed, 41 insertions(+), 26 deletions(-)

diff --git a/src/parser.js b/src/parser.js
index 105968bf..502b9c18 100644
--- a/src/parser.js
+++ b/src/parser.js
@@ -10,7 +10,7 @@ import lex, { SourceType } from 'coffee-lex';
 import locationsEqual from './util/locationsEqual';
 import locationContainingNodes from './util/locationContainingNodes';
 import locationWithLastPosition from './util/locationWithLastPosition';
-import makeNode, { Bool, RegexFlags } from './nodes';
+import makeNode, { RegexFlags } from './nodes';
 import mapAny from './mappers/mapAny';
 import mapLiteral from './mappers/mapLiteral';
 import mergeLocations from './util/mergeLocations';
@@ -653,16 +653,23 @@ function convert(context) {
         }
 
       case 'While': {
-        const result = makeNode(context, 'While', locationContainingNodes(node, node.condition, node.body), {
+        let start = linesAndColumns.indexForLocation({ line: node.locationData.first_line, column: node.locationData.first_column });
+        let tokens = context.sourceTokens;
+        let startTokenIndex = tokens.indexOfTokenContainingSourceIndex(start);
+        let startTokenType = tokens.tokenAtIndex(startTokenIndex).type;
+
+        if (startTokenType === SourceType.LOOP) {
+          return makeNode(context, 'Loop', locationContainingNodes(node, node.body), {
+            body: convertChild(node.body)
+          });
+        }
+
+        return makeNode(context, 'While', locationContainingNodes(node, node.condition, node.body), {
           condition: convertChild(node.condition),
           guard: convertChild(node.guard),
           body: convertChild(node.body),
           isUntil: node.condition.inverted === true
         });
-        if (result.raw.indexOf('loop') === 0) {
-          result.condition = Bool.true();
-        }
-        return result;
       }
 
       case 'Existence':
diff --git a/test/examples/loop/output.json b/test/examples/loop/output.json
index 3a4e7f57..c9b221d8 100644
--- a/test/examples/loop/output.json
+++ b/test/examples/loop/output.json
@@ -2,47 +2,55 @@
   "type": "Program",
   "line": 1,
   "column": 1,
-  "range": [ 0, 8 ],
+  "range": [
+    0,
+    8
+  ],
   "raw": "loop\n  a",
   "body": {
     "type": "Block",
     "line": 1,
     "column": 1,
-    "range": [ 0, 8 ],
-    "raw": "loop\n  a",
+    "range": [
+      0,
+      8
+    ],
     "statements": [
       {
-        "type": "While",
+        "type": "Loop",
         "line": 1,
         "column": 1,
-        "range": [ 0, 8 ],
-        "raw": "loop\n  a",
-        "isUntil": false,
-        "guard": null,
+        "range": [
+          0,
+          8
+        ],
         "body": {
           "type": "Block",
           "line": 2,
           "column": 3,
-          "range": [ 7, 8 ],
-          "raw": "a",
-          "inline": false,
+          "range": [
+            7,
+            8
+          ],
           "statements": [
             {
               "type": "Identifier",
               "line": 2,
               "column": 3,
-              "range": [ 7, 8 ],
+              "range": [
+                7,
+                8
+              ],
               "raw": "a",
               "data": "a"
             }
-          ]
+          ],
+          "raw": "a",
+          "inline": false
         },
-        "condition": {
-          "type": "Bool",
-          "data": true,
-          "virtual": true
-        }
+        "raw": "loop\n  a"
       }
-    ]
+    ],
+    "raw": "loop\n  a"
   }
-}
\ No newline at end of file
+}