Merge pull request #8289 from valtech-nyc/implement-smart-pipeline-in-parser

Implement Smart Pipeline proposal in @babel/parser

packages/babel-parser/src/tokenizer/index.js

@@ -374,7 +374,36 @@ export default class Tokenizer extends LocationParser {
   // into it.
   //
   // All in the name of speed.
-  //
+
+  // number sign is "#"
+  readToken_numberSign(): void {
+    if (this.state.pos === 0 && this.readToken_interpreter()) {
+      return;
+    }
+
+    const nextPos = this.state.pos + 1;
+    const next = this.input.charCodeAt(nextPos);
+    if (next >= charCodes.digit0 && next <= charCodes.digit9) {
+      this.raise(this.state.pos, "Unexpected digit after hash token");
+    }
+
+    if (
+      (this.hasPlugin("classPrivateProperties") ||
+        this.hasPlugin("classPrivateMethods")) &&
+      this.state.classLevel > 0
+    ) {
+      ++this.state.pos;
+      this.finishToken(tt.hash);
+      return;
+    } else if (
+      this.getPluginOption("pipelineOperator", "proposal") === "smart"
+    ) {
+      this.finishOp(tt.hash, 1);
+    } else {
+      this.raise(this.state.pos, "Unexpected character '#'");
+    }
+  }
+
   readToken_dot(): void {
     const next = this.input.charCodeAt(this.state.pos + 1);
     if (next >= charCodes.digit0 && next <= charCodes.digit9) {
@@ -623,24 +652,8 @@ export default class Tokenizer extends LocationParser {
   getTokenFromCode(code: number): void {
     switch (code) {
       case charCodes.numberSign:
-        if (this.state.pos === 0 && this.readToken_interpreter()) {
-          return;
-        }
-
-        if (
-          (this.hasPlugin("classPrivateProperties") ||
-            this.hasPlugin("classPrivateMethods")) &&
-          this.state.classLevel > 0
-        ) {
-          ++this.state.pos;
-          this.finishToken(tt.hash);
-          return;
-        } else {
-          this.raise(
-            this.state.pos,
-            `Unexpected character '${String.fromCodePoint(code)}'`,
-          );
-        }
+        this.readToken_numberSign();
+        return;
 
       // The interpretation of a dot depends on whether it is followed
       // by a digit or another two dots.

packages/babel-parser/src/tokenizer/state.js

@@ -6,7 +6,7 @@ import { Position } from "../util/location";
 
 import { types as ct, type TokContext } from "./context";
 import type { Token } from "./index";
-import { types as tt, type TokenType } from "./types";
+import { types as tt, type TokenType, type TopicContextState } from "./types";
 
 export default class State {
   init(options: Options, input: string): void {
@@ -26,6 +26,7 @@ export default class State {
     this.maybeInArrowParameters = false;
     this.inGenerator = false;
     this.inAsync = false;
+    this.inPipeline = false;
     this.inPropertyName = false;
     this.inType = false;
     this.inClassProperty = false;
@@ -33,6 +34,12 @@ export default class State {
     this.hasFlowComment = false;
     this.isIterator = false;
 
+    // Used by smartPipelines.
+    this.topicContext = {
+      maxNumOfResolvableTopics: 0,
+      maxTopicIndex: null,
+    };
+
     this.classLevel = 0;
 
     this.labels = [];
@@ -104,6 +111,7 @@ export default class State {
   inGenerator: boolean;
   inMethod: boolean | N.MethodKind;
   inAsync: boolean;
+  inPipeline: boolean;
   inType: boolean;
   noAnonFunctionType: boolean;
   inPropertyName: boolean;
@@ -111,6 +119,9 @@ export default class State {
   hasFlowComment: boolean;
   isIterator: boolean;
 
+  // For the smartPipelines plugin:
+  topicContext: TopicContextState;
+
   // Check whether we are in a (nested) class or not.
   classLevel: number;
 

packages/babel-parser/src/tokenizer/types.js

@@ -193,3 +193,17 @@ export const keywords = {
 Object.keys(keywords).forEach(name => {
   types["_" + name] = keywords[name];
 });
+
+// A type for the smartPipelines plugin.
+export type TopicContextState = {
+  // When a topic binding has been currently established,
+  // then this is 1. Otherwise, it is 0. This is forwards compatible
+  // with a future plugin for multiple lexical topics.
+  maxNumOfResolvableTopics: number,
+
+  // When a topic binding has been currently established, and if that binding
+  // has been used as a topic reference `#`, then this is 0. Otherwise, it is
+  // `null`. This is forwards compatible with a future plugin for multiple
+  // lexical topics.
+  maxTopicIndex: null | 0,
+};