This document specifies deprecated extensions to the ESTree API that were at one point supported in Mozilla's SpiderMonkey JavaScript engine for features that were experimental or came from defunct standards. - [Functions](#functions) - [Statements](#statements) - [ForInStatement](#forinstatement) - [LetStatement](#letstatement) - [SwitchStatement](#switchstatement) - [TryStatement](#trystatement) - [Expressions](#expressions) - [ComprehensionExpression](#comprehensionexpression) - [GeneratorExpression](#generatorexpression) - [GraphExpression](#graphexpression) - [GraphIndexExpression](#graphindexexpression) - [LetExpression](#letexpression) - [Clauses](#clauses) - [CatchClause](#catchclause) - [ComprehensionBlock](#comprehensionblock) - [Miscellaneous](#miscellaneous) - [BinaryOperator](#binaryoperator) - [E4X](#e4x) - [Declarations](#declarations) - [XMLDefaultDeclaration](#xmldefaultdeclaration) - [Expressions](#expressions-1) - [XMLAnyName](#xmlanyname) - [XMLQualifiedIdentifier](#xmlqualifiedidentifier) - [XMLFunctionQualifiedIdentifier](#xmlfunctionqualifiedidentifier) - [XMLAttributeSelector](#xmlattributeselector) - [XMLFilterExpression](#xmlfilterexpression) - [XMLElement](#xmlelement) - [XMLList](#xmllist) - [XML](#xml) - [XMLEscape](#xmlescape) - [XMLText](#xmltext) - [XMLStartTag](#xmlstarttag) - [XMLEndTag](#xmlendtag) - [XMLPointTag](#xmlpointtag) - [XMLName](#xmlname) - [XMLAttribute](#xmlattribute) - [XMLCdata](#xmlcdata) - [XMLComment](#xmlcomment) - [XMLProcessingInstruction](#xmlprocessinginstruction) # Functions ```js extend interface Function { body: BlockStatement | Expression; expression: boolean; } ``` If the `expression` flag is true, the function is an [expression closure](https://developer.mozilla.org/en-US/docs/Web/JavaScript/New_in_JavaScript/1.8#Expression_closures_%28Merge_into_own_page.2fsection%29) and the `body` field is an expression. # Statements ## ForInStatement ```js extend interface ForInStatement { each: boolean; } ``` If `each` is true, a `for each`/`in` statement. ## LetStatement ```js interface LetStatement <: Statement { type: "LetStatement"; head: [ VariableDeclarator ]; body: Statement; } ``` A `let` statement. ## SwitchStatement ```js extend interface SwitchStatement { lexical: boolean; } ``` The `lexical` flag is metadata indicating whether the `switch` statement contains any unnested `let` declarations (and therefore introduces a new lexical scope). ## TryStatement ```js extend interface TryStatement { handlers: [ CatchClause ]; guardedHandlers: [ CatchClause ]; } ``` The `length` of `handlers` may be any non-negative integer. # Expressions ## ComprehensionExpression ```js interface ComprehensionExpression <: Expression { type: "ComprehensionExpression"; body: Expression; blocks: [ ComprehensionBlock ]; filter: Expression | null; } ``` An array comprehension. The `blocks` array corresponds to the sequence of `for` and `for each` blocks. The optional `filter` expression corresponds to the final `if` clause, if present. ## GeneratorExpression ```js interface GeneratorExpression <: Expression { type: "GeneratorExpression"; body: Expression; blocks: [ ComprehensionBlock ]; filter: Expression | null; } ``` A generator expression. As with array comprehensions, the `blocks` array corresponds to the sequence of `for` and `for each` blocks, and the optional `filter` expression corresponds to the final `if` clause, if present. ## GraphExpression ```js interface GraphExpression <: Expression { type: "GraphExpression"; index: uint32; expression: Literal; } ``` A graph expression, aka "sharp literal," such as `#1={ self: #1# }`. ## GraphIndexExpression ```js interface GraphIndexExpression <: Expression { type: "GraphIndexExpression"; index: uint32; } ``` A graph index expression, aka "sharp variable," such as `#1#`. ## LetExpression ```js interface LetExpression <: Expression { type: "LetExpression"; head: [ VariableDeclarator ]; body: Expression; } ``` A `let` expression. # Clauses ## CatchClause ```js extend interface CatchClause { guard: Expression | null; } ``` The optional `guard` property corresponds to the optional expression guard on the bound variable. ## ComprehensionBlock ```js interface ComprehensionBlock <: Node { type: "ComprehensionBlock"; left: Pattern; right: Expression; each: boolean; } ``` A `for` or `for each` block in an array comprehension or generator expression. # Miscellaneous ## BinaryOperator ```js extend enum BinaryOperator { ".." } ``` The `".."` token is E4X-specific. # E4X E4X was specified by [ECMA-357](http://www.ecma-international.org/publications/standards/Ecma-357.htm) but has become a defunct standard. It was implemented for several years in SpiderMonkey but was [removed starting in Firefox 21](https://bugzilla.mozilla.org/show_bug.cgi?id=788293). ## Declarations ### XMLDefaultDeclaration ```js interface XMLDefaultDeclaration <: Declaration { type: "XMLDefaultDeclaration"; namespace: Expression; } ``` A `default xml namespace` declaration. ## Expressions ### XMLAnyName ```js interface XMLAnyName <: Expression { type: "XMLAnyName"; } ``` The special E4X wildcard pseudo-identifier `*`. ### XMLQualifiedIdentifier ```js interface XMLQualifiedIdentifier <: Expression { type: "XMLQualifiedIdentifier"; left: Identifier | XMLAnyName; right: Identifier | Expression; computed: boolean; } ``` An E4X qualified identifier, i.e., a pseudo-identifier using the namespace separator `::`. If the qualified identifier has a computed name (i.e., the `id::[expr]` form), then `computed` is `true` and the `right` property is an expression. ### XMLFunctionQualifiedIdentifier ```js interface XMLFunctionQualifiedIdentifier <: Expression { type: "XMLFunctionQualifiedIdentifier"; right: Identifier | Expression; computed: boolean; } ``` An E4X identifier qualified by the `function` keyword, e.g., `function::id`. (This functionality was a non-standard SpiderMonkey extension.) ### XMLAttributeSelector ```js interface XMLAttributeSelector <: Expression { type: "XMLAttributeSelector"; attribute: Expression; } ``` An E4X attribute selector expression, i.e., an `@` expression. ### XMLFilterExpression ```js interface XMLFilterExpression <: Expression { type: "XMLFilterExpression"; left: Expression; right: Expression; } ``` An E4X list filter expression, i.e., an expression of the form `expr.(expr)`. ### XMLElement ```js interface XMLElement <: XML, Expression { type: "XMLElement"; contents: [ XML ]; } ``` An E4X literal representing a single XML element. ### XMLList ```js interface XMLList <: XML, Expression { type: "XMLList"; contents: [ XML ]; } ``` An E4X literal representing a list of XML elements. ## XML ```js interface XML <: Node { } ``` XML data. ### XMLEscape ```js interface XMLEscape <: XML { type: "XMLEscape"; expression: Expression; } ``` XML data with an escaped JavaScript expression. ### XMLText ```js interface XMLText <: XML { type: "XMLText"; text: string; } ``` Literal XML text. ### XMLStartTag ```js interface XMLStartTag <: XML { type: "XMLStartTag"; contents: [ XML ]; } ``` An XML start tag. ### XMLEndTag ```js interface XMLEndTag <: XML { type: "XMLEndTag"; contents: [ XML ]; } ``` An XML end tag. ### XMLPointTag ```js interface XMLPointTag <: XML { type: "XMLPointTag"; contents: [ XML ]; } ``` An XML point tag. ### XMLName ```js interface XMLName <: XML { type: "XMLName"; contents: string | [ XML ]; } ``` An XML name. ### XMLAttribute ```js interface XMLAttribute <: XML { type: "XMLAttribute"; value: string; } ``` An XML attribute value. ### XMLCdata ```js interface XMLCdata <: XML { type: "XMLCdata"; contents: string; } ``` An XML CDATA node. ### XMLComment ```js interface XMLComment <: XML { type: "XMLComment"; contents: string; } ``` An XML comment. ### XMLProcessingInstruction ```js interface XMLProcessingInstruction <: XML { type: "XMLProcessingInstruction"; target: string; contents: string | null; } ``` An XML processing instruction.