Antlr4在jsx中解析templateLiteral [英] Antlr4 parsing templateLiteral in jsx
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问题描述
我尝试使用在grammars-v4项目中定义的语法(
I have tried to use grammar defined in grammars-v4 project(https://github.com/antlr/grammars-v4/tree/master/javascript/jsx) to parse jsx file. When I parse the code snippet below,
let str =
`${dsName}${parameterStr ? `( ${parameterStr} )` : ""}${returns ? `{
${returns}}` : ""}`;
it shows the following error
line 2:32 at [@8,42:42='(',<8>,2:32]:no viable alternative at input '('
https://astexplorer.net/ shows it is a TemplateLiteral with conditionalExpression inside, any thoughts for parsing such grammar?
Thanks in advance.
Edit: Thanks @Bart, it works.
It works fine on the following code.
const href1 = `https://example.com/lib/downloads_${page}.htm?joinSource=${joinSource}${inviter?`&inviter=${inviter}`: ''}`;
const href2 = `https://example.com/act/kol/detail_${this.props.values.list.res.rows && this.props.values.list.res.rows[0].id}_${page}.htm?joinSource=${joinSource}${inviter?`&inviter=${inviter}`: ''}`;
解决方案
Given Mike's observation that it's the template string that is messing things up, here's a quick solution:
Changes:
JavaScriptLexerBase.java
Add the instance variable:
// Keeps track of the the current depth of nested template string backticks.
// E.g. after the X in:
//
// `${a ? `${X
//
// templateDepth will be 2. This variable is needed to determine if a `}` is a
// plain CloseBrace, or one that closes an expression inside a template string.
protected int templateDepth = 0;
JavaScriptLexer.g4
// Place TemplateCloseBrace above CloseBrace!
TemplateCloseBrace: {this.templateDepth > 0}? '}' -> popMode;
...
// Remove (or comment) TemplateStringLiteral
// TemplateStringLiteral: '`' ('\\`' | ~'`')* '`';
BackTick
: '`' {this.templateDepth++;} -> pushMode(TEMPLATE)
;
...
// Place at the end of the file:
mode TEMPLATE;
BackTickInside
: '`' {this.templateDepth--;} -> type(BackTick), popMode
;
TemplateStringStartExpression
: '${' -> pushMode(DEFAULT_MODE)
;
TemplateStringAtom
: ~[`]
;
JavaScriptParser.g4
singleExpression
: ...
| singleExpression templateStringLiteral # TemplateStringExpression // ECMAScript 6
| ...
;
literal
: ...
| templateStringLiteral
| ...
;
templateStringLiteral
: BackTick templateStringAtom* BackTick
;
templateStringAtom
: TemplateStringAtom
| TemplateStringStartExpression singleExpression TemplateCloseBrace
;
I did not fully test my solution, but it parses your example input successfully:
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