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Allow empty arrow bodies #9

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Merged
merged 5 commits into from
Apr 9, 2017
Merged

Allow empty arrow bodies #9

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287eddf
Allow empty arrow bodies
wcjohnson Apr 6, 2017
6e634cc
Remove allowEmptyBody param.
wcjohnson Apr 6, 2017
2f0d9f0
Allow empty arrow expressions
wcjohnson Apr 7, 2017
e7ff094
Add `startsExpr` to Arrow token.
wcjohnson Apr 7, 2017
a014c6a
Restore flow fixture; remove tokens
wcjohnson Apr 9, 2017
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9 changes: 7 additions & 2 deletions src/plugins/lightscript.js
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Original file line number Diff line number Diff line change
Expand Up @@ -170,6 +170,7 @@ pp.parseNumericLiteralMember = function () {

pp.parseWhiteBlock = function (allowDirectives?, isIfExpression?) {
const node = this.startNode(), indentLevel = this.state.indentLevel;
let allowEmptyBody = false;

// must start with colon or arrow
if (isIfExpression) {
Expand All @@ -178,6 +179,8 @@ pp.parseWhiteBlock = function (allowDirectives?, isIfExpression?) {
} else if (this.eat(tt.colon)) {
if (!this.isLineBreak()) return this.parseStatement(false);
} else if (this.eat(tt.arrow)) {
allowEmptyBody = true;

if (!this.isLineBreak()) {
if (this.match(tt.braceL)) {
// restart node at brace start instead of arrow start
Expand All @@ -186,7 +189,7 @@ pp.parseWhiteBlock = function (allowDirectives?, isIfExpression?) {
this.parseBlockBody(node, allowDirectives, false, tt.braceR);
this.addExtra(node, "curly", true);
return this.finishNode(node, "BlockStatement");
} else {
} else if (this.state.type.startsExpr) {
return this.parseMaybeAssign();
}
}
Expand All @@ -197,7 +200,9 @@ pp.parseWhiteBlock = function (allowDirectives?, isIfExpression?) {
// never parse directives if curly braces aren't used (TODO: document)
this.parseBlockBody(node, false, false, indentLevel);
this.addExtra(node, "curly", false);
if (!node.body.length) this.unexpected(node.start, "Expected an Indent or Statement");
if (!allowEmptyBody && !node.body.length) {
this.unexpected(node.start, "Expected an Indent or Statement");
}

return this.finishNode(node, "BlockStatement");
};
Expand Down
2 changes: 1 addition & 1 deletion src/tokenizer/types.js
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Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,7 @@ export const types = {
doubleColon: new TokenType("::", { beforeExpr }),
dot: new TokenType("."),
question: new TokenType("?", { beforeExpr }),
arrow: new TokenType("=>", { beforeExpr }),
arrow: new TokenType("=>", { beforeExpr, startsExpr }),
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ideally this would only happen when this.hasPlugin("lightscript"), but I don't think there's an easy way to do that yet. So this is fine for now.

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Yes, unfortunately this is all declarative code, running outside the context of a particular this or parser configuration. Would require major changes to the way babylon initializes itself.

template: new TokenType("template"),
ellipsis: new TokenType("...", { beforeExpr }),
backQuote: new TokenType("`", { startsExpr }),
Expand Down
266 changes: 1 addition & 265 deletions test/fixtures/flow/type-annotations/99/expected.json
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Original file line number Diff line number Diff line change
Expand Up @@ -161,269 +161,5 @@
],
"directives": []
},
"comments": [],
"tokens": [
{
"type": {
"label": "(",
"beforeExpr": true,
"startsExpr": true,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null
},
"start": 0,
"end": 1,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 1
}
}
},
{
"type": {
"label": "name",
"beforeExpr": false,
"startsExpr": true,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null
},
"value": "foo",
"start": 1,
"end": 4,
"loc": {
"start": {
"line": 1,
"column": 1
},
"end": {
"line": 1,
"column": 4
}
}
},
{
"type": {
"label": ",",
"beforeExpr": true,
"startsExpr": false,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null,
"updateContext": null
},
"start": 4,
"end": 5,
"loc": {
"start": {
"line": 1,
"column": 4
},
"end": {
"line": 1,
"column": 5
}
}
},
{
"type": {
"label": "name",
"beforeExpr": false,
"startsExpr": true,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null
},
"value": "bar",
"start": 6,
"end": 9,
"loc": {
"start": {
"line": 1,
"column": 6
},
"end": {
"line": 1,
"column": 9
}
}
},
{
"type": {
"label": ")",
"beforeExpr": false,
"startsExpr": false,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null
},
"start": 9,
"end": 10,
"loc": {
"start": {
"line": 1,
"column": 9
},
"end": {
"line": 1,
"column": 10
}
}
},
{
"type": {
"label": ":",
"beforeExpr": true,
"startsExpr": false,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null,
"updateContext": null
},
"start": 10,
"end": 11,
"loc": {
"start": {
"line": 1,
"column": 10
},
"end": {
"line": 1,
"column": 11
}
}
},
{
"type": {
"label": "name",
"beforeExpr": false,
"startsExpr": true,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null
},
"value": "z",
"start": 12,
"end": 13,
"loc": {
"start": {
"line": 1,
"column": 12
},
"end": {
"line": 1,
"column": 13
}
}
},
{
"type": {
"label": "=>",
"beforeExpr": true,
"startsExpr": false,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null,
"updateContext": null
},
"start": 14,
"end": 16,
"loc": {
"start": {
"line": 1,
"column": 14


},
"end": {
"line": 1,
"column": 16
}
}
},
{
"type": {
"label": "null",
"keyword": "null",
"beforeExpr": false,
"startsExpr": true,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null,
"updateContext": null
},
"value": "null",
"start": 17,
"end": 21,
"loc": {
"start": {
"line": 1,
"column": 17
},
"end": {
"line": 1,
"column": 21
}
}
},
{
"type": {
"label": "eof",
"beforeExpr": false,
"startsExpr": false,
"rightAssociative": false,
"isLoop": false,
"isAssign": false,
"prefix": false,
"postfix": false,
"binop": null,
"updateContext": null
},
"start": 21,
"end": 21,
"loc": {
"start": {
"line": 1,
"column": 21
},
"end": {
"line": 1,
"column": 21
}
}
}
]
"comments": []
}
1 change: 1 addition & 0 deletions test/fixtures/lightscript/arrow-expressions/skinny-empty-double/actual.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
-> ->
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