Pipeline Operator proposal #742

hzoo · 2017-09-28T13:00:34Z

Ref babel/proposals#29
Taken from babel/babel#3159 by @gilbert
Spec: https://github.com/tc39/proposal-pipeline-operator/pull/51/files

need more tests

precedence
with arrow function 10 |> x => x + 1;
chaining a |> b |> c
multline

let result = "hello"
  |> doubleSay
  |> capitalize
  |> exclaim;

let newScore = person.score
  |> double
  |> _ => add(7, _)
  |> _ => boundScore(0, 100, _);

jridgewell · 2017-09-28T14:39:25Z

src/tokenizer/index.js

+    if (code === 124) {
+      // '|>'
+      if (next === 62) {
+        this.expectPlugin("pipelineOperator");


Don't we usually expect in the not-tokenizer part?

jridgewell · 2017-09-28T14:39:52Z

src/tokenizer/index.js

@@ -411,9 +411,17 @@ export default class Tokenizer extends LocationParser {
    const next = this.input.charCodeAt(this.state.pos + 1);


Please rename the function.

this is ok now

jridgewell · 2017-09-28T14:41:04Z

test/fixtures/experimental/pipeline-operator/base/actual.js

@@ -0,0 +1 @@
+a |> b


More examples, especially arrows.

littledan · 2017-09-30T15:18:47Z

src/tokenizer/types.js

@@ -61,7 +61,7 @@ export class TokenType {
    this.isAssign = !!conf.isAssign;
    this.prefix = !!conf.prefix;
    this.postfix = !!conf.postfix;
-    this.binop = conf.binop || null;
+    this.binop = conf.binop === 0 ? 0 : conf.binop || null;


This will be nice with ?? :)

Yes, should be easy to add/use here (would be good to find this kind of code on github/codebase and then do a codemod)

littledan · 2017-09-30T15:25:22Z

src/parser/expression.js

+        if (node.operator === "|>") {
+          this.expectPlugin("pipelineOperator");
+          // Support syntax such as 10 |> x => x + 1
+          this.state.potentialArrowAt = startPos;


I don't think the current draft spec has this logic. I couldn't figure out how to put it into the grammar. Right now, x |> y => z would be a syntax error. But it's clearly useful--i'll think more about the spec.

Good to know tc39/proposal-pipeline-operator#60

hzoo changed the title ~~pipelineOperator proposal~~ Pipeline Operator proposal Sep 28, 2017

hzoo requested a review from littledan September 28, 2017 13:02

hzoo mentioned this pull request Sep 28, 2017

Pipeline Operator (Stage 1) babel/proposals#29

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jridgewell suggested changes Sep 28, 2017

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pipelineOperator proposal

20a70a2

hzoo force-pushed the pipeline branch from 1188446 to 20a70a2 Compare September 28, 2017 17:05

hzoo added the Tag: New Feature label Sep 28, 2017

jridgewell approved these changes Sep 29, 2017

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hzoo merged commit d2e06a9 into master Sep 29, 2017

hzoo added the Spec: Pipeline Operator label Sep 29, 2017

jridgewell deleted the pipeline branch September 29, 2017 03:25

littledan reviewed Sep 30, 2017

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Pipeline Operator proposal #742

Pipeline Operator proposal #742

hzoo commented Sep 28, 2017 •

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jridgewell Sep 28, 2017

jridgewell Sep 28, 2017

hzoo Sep 28, 2017

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hzoo Sep 28, 2017

littledan Sep 30, 2017

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littledan Sep 30, 2017

hzoo Sep 30, 2017 •

edited

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		@@ -411,9 +411,17 @@ export default class Tokenizer extends LocationParser {
		const next = this.input.charCodeAt(this.state.pos + 1);

Pipeline Operator proposal #742

Pipeline Operator proposal #742

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hzoo commented Sep 28, 2017 • edited Loading

need more tests

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hzoo Sep 30, 2017 • edited Loading

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hzoo commented Sep 28, 2017 •

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hzoo Sep 30, 2017 •

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