Add support for named parameters in mappings

Author: zemse

src/nodes/Mapping.js

@@ -1,11 +1,19 @@
 const Mapping = {
-  print: ({ path, print }) => [
-    'mapping(',
-    path.call(print, 'keyType'),
-    ' => ',
-    path.call(print, 'valueType'),
-    ')'
-  ]
+  print: ({ path, print }) => {
+    const keyType = path.call(print, 'keyType');
+    const keyName = path.call(print, 'keyName');
+    const valueType = path.call(print, 'valueType');
+    const valueName = path.call(print, 'valueName');
+    return [
+      'mapping(',
+      keyType,
+      keyName ? ` ${keyName}` : '',
+      ' => ',
+      valueType,
+      valueName ? ` ${valueName}` : '',
+      ')'
+    ];
+  }
 };
 
 module.exports = Mapping;

tests/format/AllSolidityFeatures/AllSolidityFeatures.sol

@@ -88,6 +88,8 @@ contract c {
   function setData(uint pos, uint value) internal { data[pos] = value; }
   function getData(uint pos) internal { return data[pos]; }
   mapping(uint => uint) data;
+  mapping(uint id => uint ) data;
+  mapping(address owner => mapping(address spender => uint  amount)) allowances;
 }
 
 contract Sharer {

tests/format/AllSolidityFeatures/__snapshots__/jsfmt.spec.js.snap

@@ -96,6 +96,8 @@ contract c {
   function setData(uint pos, uint value) internal { data[pos] = value; }
   function getData(uint pos) internal { return data[pos]; }
   mapping(uint => uint) data;
+  mapping(uint id => uint ) data;
+  mapping(address owner => mapping(address spender => uint  amount)) allowances;
 }
 
 contract Sharer {
@@ -651,6 +653,8 @@ contract c {
     }
 
     mapping(uint => uint) data;
+    mapping(uint id => uint) data;
+    mapping(address owner => mapping(address spender => uint amount)) allowances;
 }
 
 contract Sharer {