Merge pull request #16 from GeoffreyBooth/value-ast-ast-methods

AST methods

lib/coffeescript/nodes.js

@@ -4,7 +4,7 @@
   // nodes are created as the result of actions in the [grammar](grammar.html),
   // but some are created by other nodes as a method of code generation. To convert
   // the syntax tree into a string of JavaScript code, call `compile()` on the root.
-  var Access, Arr, Assign, AwaitReturn, Base, Block, BooleanLiteral, CSXTag, Call, Class, Code, CodeFragment, ComputedPropertyName, Elision, ExecutableClassBody, Existence, Expansion, ExportAllDeclaration, ExportDeclaration, ExportDefaultDeclaration, ExportNamedDeclaration, ExportSpecifier, ExportSpecifierList, Extends, For, FuncGlyph, HEREGEX_OMIT, HereComment, HoistTarget, IdentifierLiteral, If, ImportClause, ImportDeclaration, ImportDefaultSpecifier, ImportNamespaceSpecifier, ImportSpecifier, ImportSpecifierList, In, Index, InfinityLiteral, Interpolation, JS_FORBIDDEN, LEADING_BLANK_LINE, LEVEL_ACCESS, LEVEL_COND, LEVEL_LIST, LEVEL_OP, LEVEL_PAREN, LEVEL_TOP, LineComment, Literal, ModuleDeclaration, ModuleSpecifier, ModuleSpecifierList, NEGATE, NO, NaNLiteral, NullLiteral, NumberLiteral, Obj, Op, Param, Parens, PassthroughLiteral, PropertyName, Range, RegexLiteral, RegexWithInterpolations, Return, SIMPLENUM, SIMPLE_STRING_OMIT, STRING_OMIT, Scope, Slice, Splat, StatementLiteral, StringLiteral, StringWithInterpolations, Super, SuperCall, Switch, TAB, THIS, TRAILING_BLANK_LINE, TaggedTemplateCall, ThisLiteral, Throw, Try, UTILITIES, UndefinedLiteral, Value, While, YES, YieldReturn, addDataToNode, attachCommentsToNode, compact, del, ends, extend, flatten, fragmentsToText, greater, hasLineComments, indentInitial, isFunction, isLiteralArguments, isLiteralThis, isNumber, isPlainObject, isUnassignable, lesser, locationDataToString, makeDelimitedLiteral, merge, mergeAstLocationData, moveComments, multident, replaceUnicodeCodePointEscapes, shouldCacheOrIsAssignable, some, starts, throwSyntaxError, unfoldSoak, unshiftAfterComments, utility,
+  var Access, Arr, Assign, AwaitReturn, Base, Block, BooleanLiteral, CSXTag, Call, Class, Code, CodeFragment, ComputedPropertyName, Elision, ExecutableClassBody, Existence, Expansion, ExportAllDeclaration, ExportDeclaration, ExportDefaultDeclaration, ExportNamedDeclaration, ExportSpecifier, ExportSpecifierList, Extends, For, FuncGlyph, HEREGEX_OMIT, HereComment, HoistTarget, IdentifierLiteral, If, ImportClause, ImportDeclaration, ImportDefaultSpecifier, ImportNamespaceSpecifier, ImportSpecifier, ImportSpecifierList, In, Index, InfinityLiteral, Interpolation, JS_FORBIDDEN, LEADING_BLANK_LINE, LEVEL_ACCESS, LEVEL_COND, LEVEL_LIST, LEVEL_OP, LEVEL_PAREN, LEVEL_TOP, LineComment, Literal, ModuleDeclaration, ModuleSpecifier, ModuleSpecifierList, NEGATE, NO, NaNLiteral, NullLiteral, NumberLiteral, Obj, Op, Param, Parens, PassthroughLiteral, PropertyName, Range, RegexLiteral, RegexWithInterpolations, Return, SIMPLENUM, SIMPLE_STRING_OMIT, STRING_OMIT, Scope, Slice, Splat, StatementLiteral, StringLiteral, StringWithInterpolations, Super, SuperCall, Switch, TAB, THIS, TRAILING_BLANK_LINE, TaggedTemplateCall, ThisLiteral, Throw, Try, UTILITIES, UndefinedLiteral, Value, While, YES, YieldReturn, addDataToNode, attachCommentsToNode, compact, del, ends, extend, flatten, fragmentsToText, greater, hasLineComments, indentInitial, isFunction, isLiteralArguments, isLiteralThis, isNumber, isPlainObject, isUnassignable, lesser, locationDataToString, makeDelimitedLiteral, merge, mergeAstLocationData, mergeLocationData, moveComments, multident, replaceUnicodeCodePointEscapes, shouldCacheOrIsAssignable, some, starts, throwSyntaxError, unfoldSoak, unshiftAfterComments, utility,
     indexOf = [].indexOf,
     splice = [].splice,
     slice1 = [].slice;
@@ -1555,6 +1555,7 @@
         }
         this.base = base;
         this.properties = props || [];
+        this.tag = tag;
         if (tag) {
           this[tag] = true;
         }
@@ -1665,9 +1666,9 @@
       }
 
       isSplice() {
-        var lastProp, ref1;
-        ref1 = this.properties, [lastProp] = slice1.call(ref1, -1);
-        return lastProp instanceof Slice;
+        var lastProperty, ref1;
+        ref1 = this.properties, [lastProperty] = slice1.call(ref1, -1);
+        return lastProperty instanceof Slice;
       }
 
       looksStatic(className) {
@@ -1740,28 +1741,6 @@
         return fragments;
       }
 
-      ast() {
-        var j, len1, prop, propIndex, ref1, ref2, ret;
-        ret = this.base.ast();
-        ref1 = this.properties;
-        for (propIndex = j = 0, len1 = ref1.length; j < len1; propIndex = ++j) {
-          prop = ref1[propIndex];
-          ret = {
-            type: 'MemberExpression',
-            object: ret,
-            property: prop.ast(),
-            computed: prop instanceof Index || !(((ref2 = prop.name) != null ? ref2.unwrap() : void 0) instanceof PropertyName),
-            optional: !!prop.soak,
-            shorthand: !!prop.shorthand
-          };
-          // When the `Value` has properties, the location data of a `MemberExpression` AST node
-          // corresponding to a given property should span the location of the `Value`'s `base`
-          // (including parens if present) through the property's location
-          Object.assign(ret, mergeAstLocationData(this.base.astLocationData(), prop.astLocationData()));
-        }
-        return ret;
-      }
-
       checkNewTarget(o) {
         if (!(this.base instanceof IdentifierLiteral && this.base.value === 'new' && this.properties.length)) {
           return;
@@ -1816,6 +1795,60 @@
         }
       }
 
+      // For AST generation, we need an `object` that’s this `Value` minus its last
+      // property, if it has properties.
+      object() {
+        var initialProperties, object;
+        if (!this.hasProperties()) {
+          return this;
+        }
+        // Get all properties except the last one; for a `Value` with only one
+        // property, `initialProperties` is an empty array.
+        initialProperties = this.properties.slice(0, this.properties.length - 1);
+        // Create the `object` that becomes the new “base” for the split-off final
+        // property.
+        object = new Value(this.base, initialProperties, this.tag, this.isDefaultValue);
+        // Add location data to our new node, so that it has correct location data
+        // for source maps or later conversion into AST location data.
+        // This new `Value` has only one property, so the location data is just
+        // that of the parent `Value`’s base.
+        // This new `Value` has multiple properties, so the location data spans
+        // from the parent `Value`’s base to the last property that’s included
+        // in this new node (a.k.a. the second-to-last property of the parent).
+        object.locationData = initialProperties.length === 0 ? this.base.locationData : mergeLocationData(this.base.locationData, initialProperties[initialProperties.length - 1].locationData);
+        return object;
+      }
+
+      ast() {
+        if (!this.hasProperties()) {
+          // If the `Value` has no properties, the AST node is just whatever this
+          // node’s `base` is.
+          return this.base.ast();
+        }
+        // Otherwise, call `Base::ast` which in turn calls the `astType` and
+        // `astProperties` methods below.
+        return super.ast();
+      }
+
+      astType() {
+        return 'MemberExpression';
+      }
+
+      // If this `Value` has properties, the *last* property (e.g. `c` in `a.b.c`)
+      // becomes the `property`, and the preceding properties (e.g. `a.b`) become
+      // a child `Value` node assigned to the `object` property.
+      astProperties() {
+        var property, ref1, ref2;
+        ref1 = this.properties, [property] = slice1.call(ref1, -1);
+        return {
+          object: this.object().ast(),
+          property: property.ast(),
+          computed: property instanceof Index || !(((ref2 = property.name) != null ? ref2.unwrap() : void 0) instanceof PropertyName),
+          optional: !!property.soak,
+          shorthand: !!property.shorthand
+        };
+      }
+
     };
 
     Value.prototype.children = ['base', 'properties'];
@@ -2284,6 +2317,9 @@
       }
 
       ast() {
+        // Babel doesn’t have an AST node for `Access`, but rather just includes
+        // this Access node’s child `name` Identifier node as the `property` of
+        // the `MemberExpression` node.
         return this.name.ast();
       }
 
@@ -2311,14 +2347,19 @@
         return [].concat(this.makeCode("["), this.index.compileToFragments(o, LEVEL_PAREN), this.makeCode("]"));
       }
 
-      ast() {
-        return this.index.ast();
-      }
-
       shouldCache() {
         return this.index.shouldCache();
       }
 
+      ast() {
+        // Babel doesn’t have an AST node for `Index`, but rather just includes
+        // this Index node’s child `index` Identifier node as the `property` of
+        // the `MemberExpression` node. The fact that the `MemberExpression`’s
+        // `property` is an Index means that `computed` is `true` for the
+        // `MemberExpression`.
+        return this.index.ast();
+      }
+
     };
 
     Index.prototype.children = ['index'];
@@ -5171,9 +5212,9 @@
   //### In
   exports.In = In = (function() {
     class In extends Base {
-      constructor(object, array) {
+      constructor(object1, array) {
         super();
-        this.object = object;
+        this.object = object1;
         this.array = array;
       }
 
@@ -6299,10 +6340,7 @@
     return `${options.delimiter}${body}${options.delimiter}`;
   };
 
-  // Take two AST nodes, or two AST nodes’ location data objects, and return a new
-  // location data object that encompasses the location data of both nodes. So the
-  // new `start` value will be the earlier of the two nodes’ `start` values, the
-  // new `end` value will be the later of the two nodes’ `end` values, etc.
+  // Helpers for `mergeLocationData` and `mergeAstLocationData` below.
   lesser = function(a, b) {
     if (a < b) {
       return a;
@@ -6319,6 +6357,24 @@
     }
   };
 
+  // Take two nodes’ location data and return a new `locationData` object that
+  // encompasses the location data of both nodes. So the new `first_line` value
+  // will be the earlier of the two nodes’ `first_line` values, the new
+  // `last_column` the later of the two nodes’ `last_column` values, etc.
+  mergeLocationData = function(locationDataA, locationDataB) {
+    return {
+      first_line: lesser(locationDataA.first_line, locationDataB.first_line),
+      first_column: lesser(locationDataA.first_column, locationDataB.first_column),
+      last_line: greater(locationDataA.last_line, locationDataB.last_line),
+      last_column: greater(locationDataA.last_column, locationDataB.last_column),
+      range: [lesser(locationDataA.range[0], locationDataB.range[0]), greater(locationDataA.range[1], locationDataB.range[1])]
+    };
+  };
+
+  // Take two AST nodes, or two AST nodes’ location data objects, and return a new
+  // location data object that encompasses the location data of both nodes. So the
+  // new `start` value will be the earlier of the two nodes’ `start` values, the
+  // new `end` value will be the later of the two nodes’ `end` values, etc.
   mergeAstLocationData = function(nodeA, nodeB) {
     return {
       loc: {

src/nodes.coffee

@@ -914,6 +914,7 @@ exports.PropertyName = class PropertyName extends Literal
   isAssignable: YES
 
   astType: -> 'Identifier'
+
   astProperties: ->
     name: @value
 
@@ -1041,6 +1042,7 @@ exports.Value = class Value extends Base
     return base if not props and base instanceof Value
     @base           = base
     @properties     = props or []
+    @tag            = tag
     @[tag]          = yes if tag
     @isDefaultValue = isDefaultValue
     # If this is a `@foo =` assignment, if there are comments on `@` move them
@@ -1095,8 +1097,8 @@ exports.Value = class Value extends Base
     @base.hasElision()
 
   isSplice: ->
-    [..., lastProp] = @properties
-    lastProp instanceof Slice
+    [..., lastProperty] = @properties
+    lastProperty instanceof Slice
 
   looksStatic: (className) ->
     (@this or @base instanceof ThisLiteral or @base.value is className) and
@@ -1150,22 +1152,6 @@ exports.Value = class Value extends Base
 
     fragments
 
-  ast: ->
-    ret = @base.ast()
-    for prop, propIndex in @properties
-      ret =
-        type: 'MemberExpression'
-        object: ret
-        property: prop.ast()
-        computed: prop instanceof Index or prop.name?.unwrap() not instanceof PropertyName
-        optional: !!prop.soak
-        shorthand: !!prop.shorthand
-      # When the `Value` has properties, the location data of a `MemberExpression` AST node
-      # corresponding to a given property should span the location of the `Value`'s `base`
-      # (including parens if present) through the property's location
-      Object.assign ret, mergeAstLocationData(@base.astLocationData(), prop.astLocationData())
-    ret
-
   checkNewTarget: (o) ->
     return unless @base instanceof IdentifierLiteral and @base.value is 'new' and @properties.length
     if @properties[0] instanceof Access and @properties[0].name.value is 'target'
@@ -1200,6 +1186,52 @@ exports.Value = class Value extends Base
     else
       @error 'tried to assign to unassignable value'
 
+  # For AST generation, we need an `object` that’s this `Value` minus its last
+  # property, if it has properties.
+  object: ->
+    return @ unless @hasProperties()
+    # Get all properties except the last one; for a `Value` with only one
+    # property, `initialProperties` is an empty array.
+    initialProperties = @properties[0...@properties.length - 1]
+    # Create the `object` that becomes the new “base” for the split-off final
+    # property.
+    object = new Value @base, initialProperties, @tag, @isDefaultValue
+    # Add location data to our new node, so that it has correct location data
+    # for source maps or later conversion into AST location data.
+    object.locationData =
+      if initialProperties.length is 0
+        # This new `Value` has only one property, so the location data is just
+        # that of the parent `Value`’s base.
+        @base.locationData
+      else
+        # This new `Value` has multiple properties, so the location data spans
+        # from the parent `Value`’s base to the last property that’s included
+        # in this new node (a.k.a. the second-to-last property of the parent).
+        mergeLocationData @base.locationData, initialProperties[initialProperties.length - 1].locationData
+    object
+
+  ast: ->
+    # If the `Value` has no properties, the AST node is just whatever this
+    # node’s `base` is.
+    return @base.ast() unless @hasProperties()
+    # Otherwise, call `Base::ast` which in turn calls the `astType` and
+    # `astProperties` methods below.
+    super()
+
+  astType: -> 'MemberExpression'
+
+  # If this `Value` has properties, the *last* property (e.g. `c` in `a.b.c`)
+  # becomes the `property`, and the preceding properties (e.g. `a.b`) become
+  # a child `Value` node assigned to the `object` property.
+  astProperties: ->
+    [..., property] = @properties
+    return
+      object: @object().ast()
+      property: property.ast()
+      computed: property instanceof Index or property.name?.unwrap() not instanceof PropertyName
+      optional: !!property.soak
+      shorthand: !!property.shorthand
+
 #### HereComment
 
 # Comment delimited by `###` (becoming `/* */`).
@@ -1498,11 +1530,14 @@ exports.Access = class Access extends Base
     else
       [@makeCode('['), name..., @makeCode(']')]
 
-  ast: ->
-    @name.ast()
-
   shouldCache: NO
 
+  ast: ->
+    # Babel doesn’t have an AST node for `Access`, but rather just includes
+    # this Access node’s child `name` Identifier node as the `property` of
+    # the `MemberExpression` node.
+    @name.ast()
+
 #### Index
 
 # A `[ ... ]` indexed access into an array or object.
@@ -1515,12 +1550,17 @@ exports.Index = class Index extends Base
   compileToFragments: (o) ->
     [].concat @makeCode("["), @index.compileToFragments(o, LEVEL_PAREN), @makeCode("]")
 
-  ast: ->
-    @index.ast()
-
   shouldCache: ->
     @index.shouldCache()
 
+  ast: ->
+    # Babel doesn’t have an AST node for `Index`, but rather just includes
+    # this Index node’s child `index` Identifier node as the `property` of
+    # the `MemberExpression` node. The fact that the `MemberExpression`’s
+    # `property` is an Index means that `computed` is `true` for the
+    # `MemberExpression`.
+    @index.ast()
+
 #### Range
 
 # A range literal. Ranges can be used to extract portions (slices) of arrays,
@@ -3643,8 +3683,7 @@ exports.Parens = class Parens extends Base
     return @wrapInBraces fragments if @csxAttribute
     if bare then fragments else @wrapInParentheses fragments
 
-  ast: ->
-    @body.unwrap().ast()
+  ast: -> @body.unwrap().ast()
 
 #### StringWithInterpolations
 
@@ -4163,12 +4202,29 @@ makeDelimitedLiteral = (body, options = {}) ->
     when other     then (if options.double then "\\#{other}" else other)
   "#{options.delimiter}#{body}#{options.delimiter}"
 
+# Helpers for `mergeLocationData` and `mergeAstLocationData` below.
+lesser  = (a, b) -> if a < b then a else b
+greater = (a, b) -> if a > b then a else b
+
+# Take two nodes’ location data and return a new `locationData` object that
+# encompasses the location data of both nodes. So the new `first_line` value
+# will be the earlier of the two nodes’ `first_line` values, the new
+# `last_column` the later of the two nodes’ `last_column` values, etc.
+mergeLocationData = (locationDataA, locationDataB) ->
+  return
+    first_line:   lesser locationDataA.first_line,   locationDataB.first_line
+    first_column: lesser locationDataA.first_column, locationDataB.first_column
+    last_line:    greater locationDataA.last_line,   locationDataB.last_line
+    last_column:  greater locationDataA.last_column, locationDataB.last_column
+    range: [
+      lesser  locationDataA.range[0], locationDataB.range[0]
+      greater locationDataA.range[1], locationDataB.range[1]
+    ]
+
 # Take two AST nodes, or two AST nodes’ location data objects, and return a new
 # location data object that encompasses the location data of both nodes. So the
 # new `start` value will be the earlier of the two nodes’ `start` values, the
 # new `end` value will be the later of the two nodes’ `end` values, etc.
-lesser  = (a, b) -> if a < b then a else b
-greater = (a, b) -> if a > b then a else b
 mergeAstLocationData = (nodeA, nodeB) ->
   return
     loc:

test/abstract_syntax_tree.coffee

@@ -1113,11 +1113,10 @@ test "AST as expected for Index node", ->
 
 #   # NOTE: Soaking is covered in `Call` and `Access` nodes.
 
-# test "AST as expected for Parens node", ->
-#   testExpression '(hmmmmm)',
-#     type: 'Parens',
-#     body:
-#       type: 'Value'
+test "AST as expected for Parens node", ->
+  testExpression '(hmmmmm)',
+    type: 'Identifier'
+    name: 'hmmmmm'
 
 #   testExpression '(a + b) / c',
 #     type: 'Op'
@@ -1128,19 +1127,9 @@ test "AST as expected for Index node", ->
 #         type: 'Op'
 #         operator: '+'
 
-#   testExpression '(((1)))',
-#     type: 'Parens',
-#     body:
-#       type: 'Value'
-#       base:
-#         type: 'Block'
-#         expressions: [
-#           type: 'Parens',
-#           body:
-#             type: 'Value'
-#             base:
-#               value: '1'
-#         ]
+  testExpression '(((1)))',
+    type: 'NumericLiteral'
+    value: 1
 
 # test "AST as expected for StringWithInterpolations node", ->
 #   testExpression '"#{o}/"',

test/abstract_syntax_tree_location_data.coffee

@@ -407,3 +407,39 @@ test "AST location data as expected for Index node", ->
       end:
         line: 1
         column: 8
+
+test "AST location data as expected for Parens node", ->
+  testAstLocationData '(hmmmmm)',
+    type: 'Identifier'
+    start: 1
+    end: 7
+    range: [1, 7]
+    loc:
+      start:
+        line: 1
+        column: 1
+      end:
+        line: 1
+        column: 7
+
+#   testExpression '(a + b) / c',
+#     type: 'Op'
+#     operator: '/'
+#     first:
+#       type: 'Parens'
+#       body:
+#         type: 'Op'
+#         operator: '+'
+
+  testAstLocationData '(((1)))',
+    type: 'NumericLiteral'
+    start: 3
+    end: 4
+    range: [3, 4]
+    loc:
+      start:
+        line: 1
+        column: 3
+      end:
+        line: 1
+        column: 4