feat: add remaining CoffeeScript 1.12.7 syntax features (#313)

Progress toward decaffeinate/decaffeinate#427

Tagged template literals, for...from, and bare yield needed some parser tweaks.
The inline JS changes just worked without needing modifications here.

Author: alangpierce

src/mappers/mapAny.ts

@@ -1,6 +1,6 @@
 import {
   Arr, Assign, Base, Block, Call, Class, Code, Comment, Existence, Expansion, Extends,
-  For, If, In, Literal, ModuleDeclaration, Obj, Op, Param, Parens, Range, Return, Splat, Switch,
+  For, If, In, Literal, ModuleDeclaration, Obj, Op, Param, Parens, Range, Return, Splat, Switch, TaggedTemplateCall,
   Throw, Try, Value, While,
 } from 'decaffeinate-coffeescript/lib/coffee-script/nodes';
 import { Node } from '../nodes';
@@ -28,6 +28,7 @@ import mapRange from './mapRange';
 import mapReturn from './mapReturn';
 import mapSplat from './mapSplat';
 import mapSwitch from './mapSwitch';
+import mapTaggedTemplateCall from './mapTaggedTemplateCall';
 import mapThrow from './mapThrow';
 import mapTry from './mapTry';
 import mapValue from './mapValue';
@@ -46,6 +47,10 @@ export default function mapAny(context: ParseContext, node: Base): Node {
     return mapOp(context, node);
   }
 
+  if (node instanceof TaggedTemplateCall) {
+    return mapTaggedTemplateCall(context, node);
+  }
+
   if (node instanceof Call) {
     return mapCall(context, node);
   }

src/mappers/mapFor.ts

@@ -1,5 +1,5 @@
 import { For as CoffeeFor } from 'decaffeinate-coffeescript/lib/coffee-script/nodes';
-import { For, ForIn, ForOf } from '../nodes';
+import {For, ForFrom, ForIn, ForOf} from '../nodes';
 import getLocation from '../util/getLocation';
 import ParseContext from '../util/ParseContext';
 import mapAny from './mapAny';
@@ -31,16 +31,28 @@ export default function mapFor(context: ParseContext, node: CoffeeFor): For {
       isOwn
     );
   } else {
-    let step = node.step ? mapAny(context, node.step) : null;
-
-    return new ForIn(
-      line, column, start, end, raw,
-      keyAssignee,
-      valAssignee,
-      target,
-      filter,
-      body,
-      step
-    );
+    if (node.from) {
+      if (keyAssignee) {
+        throw new Error('Unexpected key assignee in for...from.');
+      }
+      return new ForFrom(
+        line, column, start, end, raw,
+        valAssignee,
+        target,
+        filter,
+        body,
+      );
+    } else {
+      let step = node.step ? mapAny(context, node.step) : null;
+      return new ForIn(
+        line, column, start, end, raw,
+        keyAssignee,
+        valAssignee,
+        target,
+        filter,
+        body,
+        step
+      );
+    }
   }
 }

src/mappers/mapOp.ts

@@ -1,5 +1,5 @@
 import { SourceType } from 'coffee-lex';
-import { Op as CoffeeOp } from 'decaffeinate-coffeescript/lib/coffee-script/nodes';
+import {Literal, Op as CoffeeOp, Value} from 'decaffeinate-coffeescript/lib/coffee-script/nodes';
 import { inspect } from 'util';
 import {
   BinaryOp, BitAndOp, BitNotOp, BitOrOp, BitXorOp, ChainedComparisonOp, DeleteOp, DivideOp, ExistsOp, ExpOp, EQOp, FloorDivideOp,
@@ -185,10 +185,17 @@ function mapNewOp(context: ParseContext, node: CoffeeOp): NewOp {
 
 function mapYieldOp(context: ParseContext, node: CoffeeOp): YieldReturn | Yield {
   let { line, column, start, end, raw } = getLocation(context, node);
-  return new Yield(
-    line, column, start, end, raw,
-    mapAny(context, node.first)
-  );
+  if (isBareYield(node)) {
+    return new Yield(line, column, start, end, raw, null);
+  } else {
+    return new Yield(line, column, start, end, raw, mapAny(context, node.first));
+  }
+}
+
+function isBareYield(node: CoffeeOp): boolean {
+  return node.first instanceof Value &&
+    node.first.base instanceof Literal &&
+    node.first.base.value === '';
 }
 
 interface IBinaryOp {

src/mappers/mapTaggedTemplateCall.ts

@@ -0,0 +1,21 @@
+import {TaggedTemplateCall} from 'decaffeinate-coffeescript/lib/coffee-script/nodes';
+import {Node, String, TaggedTemplateLiteral} from '../nodes';
+import getLocation from '../util/getLocation';
+import ParseContext from '../util/ParseContext';
+import mapAny from './mapAny';
+
+export default function mapTaggedTemplateCall(context: ParseContext, node: TaggedTemplateCall): Node {
+  let { line, column, start, end, raw } = getLocation(context, node);
+  if (!node.variable) {
+    throw new Error('Expected tag in tagged template literal.');
+  }
+  let tag = mapAny(context, node.variable);
+  if (node.args.length !== 1) {
+    throw new Error('Expected tagged template literal call to have exactly one argument.');
+  }
+  let template = mapAny(context, node.args[0]);
+  if (!(template instanceof String)) {
+    throw new Error('Expected tagged template literal argument to be a string.');
+  }
+  return new TaggedTemplateLiteral(line, column, start, end, raw, tag, template);
+}

src/nodes.ts

@@ -295,6 +295,24 @@ export class String extends Node {
   }
 }
 
+export class TaggedTemplateLiteral extends Node {
+  constructor(
+    line: number,
+    column: number,
+    start: number,
+    end: number,
+    raw: string,
+    readonly tag: Node,
+    readonly template: String,
+  ) {
+    super('TaggedTemplateLiteral', line, column, start, end, raw);
+  }
+
+  getChildNames(): Array<keyof this> {
+    return ['tag', 'template'];
+  }
+}
+
 export class ObjectInitialiser extends Node {
   constructor(
     line: number,
@@ -495,6 +513,26 @@ export class ForIn extends For {
   }
 }
 
+export class ForFrom extends For {
+  constructor(
+    line: number,
+    column: number,
+    start: number,
+    end: number,
+    raw: string,
+    valAssignee: Node | null,
+    target: Node,
+    filter: Node | null,
+    body: Block | null,
+  ) {
+    super('ForFrom', line, column, start, end, raw, null /* keyAssignee */, valAssignee, target, filter, body);
+  }
+
+  getChildNames(): Array<keyof this> {
+    return ['keyAssignee', 'valAssignee', 'target', 'filter', 'body'];
+  }
+}
+
 export class Switch extends Node {
   constructor(
     line: number,
@@ -1517,29 +1555,37 @@ export class DeleteOp extends UnaryOp {
   }
 }
 
-export class Yield extends UnaryOp {
+export class Yield extends Node {
   constructor(
     line: number,
     column: number,
     start: number,
     end: number,
     raw: string,
-    expression: Node,
+    readonly expression: Node | null,
   ) {
-    super('Yield', line, column, start, end, raw, expression);
+    super('Yield', line, column, start, end, raw);
+  }
+
+  getChildNames(): Array<keyof this> {
+    return ['expression'];
   }
 }
 
-export class YieldFrom extends UnaryOp {
+export class YieldFrom extends Node {
   constructor(
     line: number,
     column: number,
     start: number,
     end: number,
     raw: string,
-    expression: Node,
+    readonly expression: Node,
   ) {
-    super('YieldFrom', line, column, start, end, raw, expression);
+    super('YieldFrom', line, column, start, end, raw);
+  }
+
+  getChildNames(): Array<keyof this> {
+    return ['expression'];
   }
 }
 

test/examples/bare-yield/input.coffee

@@ -0,0 +1,2 @@
+f = ->
+  yield

test/examples/bare-yield/output.json

@@ -0,0 +1,66 @@
+{
+  "body": {
+    "column": 1,
+    "end": 14,
+    "inline": false,
+    "line": 1,
+    "raw": "f = ->\n  yield",
+    "start": 0,
+    "statements": [
+      {
+        "assignee": {
+          "column": 1,
+          "data": "f",
+          "end": 1,
+          "line": 1,
+          "raw": "f",
+          "start": 0,
+          "type": "Identifier"
+        },
+        "column": 1,
+        "end": 14,
+        "expression": {
+          "body": {
+            "column": 3,
+            "end": 14,
+            "inline": false,
+            "line": 2,
+            "raw": "yield",
+            "start": 9,
+            "statements": [
+              {
+                "column": 3,
+                "end": 14,
+                "expression": null,
+                "line": 2,
+                "raw": "yield",
+                "start": 9,
+                "type": "Yield"
+              }
+            ],
+            "type": "Block"
+          },
+          "column": 5,
+          "end": 14,
+          "line": 1,
+          "parameters": [
+          ],
+          "raw": "->\n  yield",
+          "start": 4,
+          "type": "GeneratorFunction"
+        },
+        "line": 1,
+        "raw": "f = ->\n  yield",
+        "start": 0,
+        "type": "AssignOp"
+      }
+    ],
+    "type": "Block"
+  },
+  "column": 1,
+  "end": 15,
+  "line": 1,
+  "raw": "f = ->\n  yield\n",
+  "start": 0,
+  "type": "Program"
+}

test/examples/for-from/input.coffee

@@ -0,0 +1,2 @@
+for a from b
+  c

test/examples/for-from/output.json

@@ -0,0 +1,67 @@
+{
+  "body": {
+    "column": 1,
+    "end": 16,
+    "inline": false,
+    "line": 1,
+    "raw": "for a from b\n  c",
+    "start": 0,
+    "statements": [
+      {
+        "body": {
+          "column": 3,
+          "end": 16,
+          "inline": false,
+          "line": 2,
+          "raw": "c",
+          "start": 15,
+          "statements": [
+            {
+              "column": 3,
+              "data": "c",
+              "end": 16,
+              "line": 2,
+              "raw": "c",
+              "start": 15,
+              "type": "Identifier"
+            }
+          ],
+          "type": "Block"
+        },
+        "column": 1,
+        "end": 16,
+        "filter": null,
+        "keyAssignee": null,
+        "line": 1,
+        "raw": "for a from b\n  c",
+        "start": 0,
+        "target": {
+          "column": 12,
+          "data": "b",
+          "end": 12,
+          "line": 1,
+          "raw": "b",
+          "start": 11,
+          "type": "Identifier"
+        },
+        "type": "ForFrom",
+        "valAssignee": {
+          "column": 5,
+          "data": "a",
+          "end": 5,
+          "line": 1,
+          "raw": "a",
+          "start": 4,
+          "type": "Identifier"
+        }
+      }
+    ],
+    "type": "Block"
+  },
+  "column": 1,
+  "end": 17,
+  "line": 1,
+  "raw": "for a from b\n  c\n",
+  "start": 0,
+  "type": "Program"
+}

test/examples/tagged-template-literal/input.coffee

@@ -0,0 +1 @@
+s = f"a#{b}c"