Consume one token of the specified type, or signal an error if it is not there.

semi = nl {nl} | `;`
nl  = `\n` // where allowed

AccessModifier ::= (private | protected) [AccessQualifier]

AccessQualifier ::= `[` (Id | this) `]`

Annotations       ::= {`@` SimpleType {ArgumentExprs}}
ConstrAnnotations ::= {`@` SimpleType ArgumentExprs}

ArgumentExprs ::= `(` [Exprs] `)`
                | [nl] BlockExpr

Block ::= BlockStatSeq

BlockExpr ::= `{` (CaseClauses | Block) `}`

BlockStatSeq ::= { BlockStat semi } [ResultExpr]
BlockStat    ::= Import
               | Annotations [implicit] [lazy] Def
               | Annotations LocalModifiers TmplDef
               | Expr1
               |

CaseClauses ::= CaseClause {CaseClause}
CaseClause  ::= case Pattern [Guard] `=>` Block

Check that type parameter is not by name or repeated.

ClassDef ::= Id [TypeParamClause] ConstrAnnotations
             [AccessModifier] ClassParamClauses RequiresTypeOpt ClassTemplateOpt
TraitDef ::= Id [TypeParamClause] RequiresTypeOpt TraitTemplateOpt

tokenSeparated

, with the separator fixed to commas. tokenSeparated }}}

CompilationUnit ::= {package QualId semi} TopStatSeq

ConstrBlock    ::=  `{` SelfInvocation {semi BlockStat} `}`

ConstrExpr      ::=  SelfInvocation
                  |  ConstrBlock

Convert tree to formal parameter.

Convert tree to formal parameter list.

Convert (qual)ident to type identifier.

Def    ::= val PatDef
         | var PatDef
         | def FunDef
         | type [nl] TypeDef
         | TmplDef
Dcl    ::= val PatDcl
         | var PatDcl
         | def FunDcl
         | type [nl] TypeDcl

Enumerators ::= Generator {semi Enumerator}
Enumerator  ::=  Generator
              |  Guard
              |  Pattern1 `=` Expr

Expr       ::= (Bindings | [`implicit`] Id | `_`)  `=>` Expr
             | Expr1
ResultExpr ::= (Bindings | Id `:` CompoundType) `=>` Block
             | Expr1
Expr1      ::= if `(` Expr `)` {nl} Expr [[semi] else Expr]
             | try (`{` Block `}` | Expr) [catch `{` CaseClauses `}`] [finally Expr]
             | while `(` Expr `)` {nl} Expr
             | do Expr [semi] while `(` Expr `)`
             | for (`(` Enumerators `)` | `{` Enumerators `}`) {nl} [yield] Expr
             | throw Expr
             | return [Expr]
             | [SimpleExpr `.`] Id `=` Expr
             | SimpleExpr1 ArgumentExprs `=` Expr
             | PostfixExpr Ascription
             | PostfixExpr match `{` CaseClauses `}`
Bindings   ::= `(` [Binding {`,` Binding}] `)`
Binding    ::= (Id | `_`) [`:` Type]
Ascription ::= `:` CompoundType
             | `:` Annotation {Annotation}
             | `:` `_` `*`

FunDef ::= FunSig [`:` Type] `=` [`macro`] Expr
        |  FunSig [nl] `{` Block `}`
        |  `this` ParamClause ParamClauses
               (`=` ConstrExpr | [nl] ConstrBlock)
FunDcl ::= FunSig [`:` Type]
FunSig ::= id [FunTypeParamClause] ParamClauses

Generator ::= Pattern1 (`<-` | `=`) Expr [Guard]

Guard ::= if PostfixExpr

Assumed (provisionally) to be TermNames.

For when it's known already to be a type name.

Expr ::= implicit Id `=>` Expr

Import  ::= import ImportExpr {`,` ImportExpr}

ImportExpr ::= StableId `.` (Id | `_` | ImportSelectors)

ImportSelector ::= Id [`=>` Id | `=>` `_`]

ImportSelectors ::= `{` {ImportSelector `,`} (ImportSelector | `_`) `}`

Methods inParensOrError and similar take a second argument which, should the next token not be the expected opener (e.g. LPAREN) will be returned instead of the contents of the groupers. However in all cases accept(LPAREN) will be called, so a parse error will still result. If the grouping is optional, in.token should be tested before calling these methods.

Skip trailing comma is pushed down to scanner because this abstract parser doesn't have token info.

A hook for joining the comment associated with a definition. Overridden by scaladoc.

SimpleExpr    ::= literal
                | symbol
                | null

overridable IDE hook for local definitions of blockStatSeq Here's an idea how to fill in start and end positions. def localDef : List[Tree] = { atEndPos { atStartPos(in.offset) { val annots = annotations(skipNewLines = true) val mods = localModifiers() withAnnotations annots if (!(mods hasFlag ~(Flags.IMPLICIT | Flags.LAZY))) defOrDcl(mods) else List(tmplDef(mods)) } } (in.offset) }

LocalModifiers ::= {LocalModifier}
LocalModifier  ::= abstract | final | sealed | implicit | lazy

Scoping operator used to temporarily look into the future. Backs up scanner data before evaluating a block and restores it after.

Create tree representing (unencoded) binary operation expression or pattern.

Create a tree representing a packaging.

Creates an actual Parens node (only used during parsing.)

Create a function Tree. If the arity is not supported, a syntax error is emitted.

Create a tuple term Tree. If the arity is not supported, a syntax error is emitted.

Create a tuple type Tree. If the arity is not supported, a syntax error is emitted.

MixinQualifier ::= `[` Id `]`

Modifiers ::= {Modifier}
Modifier  ::= LocalModifier
            |  AccessModifier
            |  override

A succession of argument lists.

The implementation for parsing inside of patterns at points where sequences are disallowed.

ObjectDef       ::= Id ClassTemplateOpt

The implementation of the context sensitive methods for parsing outside of patterns.

Create a tree representing a package object, converting

package object foo { ... }

to

package foo {
  object `package` { ... }
}

ParamClauses      ::= {ParamClause} [[nl] `(` implicit Params `)`]
ParamClause       ::= [nl] `(` [Params] `)`
Params            ::= Param {`,` Param}
Param             ::= {Annotation} Id [`:` ParamType] [`=` Expr]
ClassParamClauses ::= {ClassParamClause} [[nl] `(` implicit ClassParams `)`]
ClassParamClause  ::= [nl] `(` [ClassParams] `)`
ClassParams       ::= ClassParam {`,` ClassParam}
ClassParam        ::= {Annotation}  [{Modifier} (`val` | `var`)] Id [`:` ParamType] [`=` Expr]

ParamType ::= Type | `=>` Type | Type `*`

This is the general parse entry point.

The parse starting point depends on whether the source file is self-contained: if not, the AST will be supplemented.

These are alternative entry points for repl, script runner, toolbox and parsing in macros.

PatDef ::= Pattern2 {`,` Pattern2} [`:` Type] `=` Expr
ValDcl ::= Id {`,` Id} `:` Type
VarDef ::= PatDef | Id {`,` Id} `:` Type `=` `_`

Path       ::= StableId
            |  [Ident `.`] this
AnnotType ::= Path [`.` type]

Default entry points into some pattern contexts.

Perform an operation while peeking ahead. Pushback if the operation yields an empty tree or blows to pieces.

The implicit parameters introduced by _ in the current expression. Parameters appear in reverse order.

The placeholderTypes introduced by _ in the current type. Parameters appear in reverse order.

PostfixExpr   ::= InfixExpr [Id [nl]]
InfixExpr     ::= PrefixExpr
                | InfixExpr Id [nl] InfixExpr

PrefixExpr   ::= [`-` | `+` | `~` | `!`] SimpleExpr

QualId ::= Id {`.` Id}

RefineStatSeq    ::= RefineStat {semi RefineStat}
RefineStat       ::= Dcl
                   | type TypeDef
                   |

Refinement ::= [nl] `{` RefineStat {semi RefineStat} `}`

This is the parse entry point for code which is not self-contained, e.g. a script which is a series of template statements. They will be swaddled in Trees until the AST is equivalent to the one returned by compilationUnit().

SelfInvocation  ::= this ArgumentExprs {ArgumentExprs}

{ `sep` part }

. { sep part } }}}

The implementation for parsing inside of patterns at points where sequences are allowed.

SimpleExpr    ::= new (ClassTemplate | TemplateBody)
                |  BlockExpr
                |  SimpleExpr1 [`_`]
SimpleExpr1   ::= literal
                |  xLiteral
                |  Path
                |  `(` [Exprs] `)`
                |  SimpleExpr `.` Id
                |  SimpleExpr TypeArgs
                |  SimpleExpr1 ArgumentExprs

StableId ::= Id
          |  Path `.` Id
          |  [id `.`] super [`[` id `]`]`.` id

Strip the artificial Parens node to create a tuple term Tree.

ClassTemplate ::= [EarlyDefs with] ClassParents [TemplateBody]
TraitTemplate ::= [EarlyDefs with] TraitParents [TemplateBody]
EarlyDefs     ::= `{` [EarlyDef {semi EarlyDef}] `}`
EarlyDef      ::= Annotations Modifiers PatDef

TemplateBody ::= [nl] `{` TemplateStatSeq `}`

ClassTemplateOpt ::= `extends` ClassTemplate | [[`extends`] TemplateBody]
TraitTemplateOpt ::= TraitExtends TraitTemplate | [[TraitExtends] TemplateBody]
TraitExtends     ::= `extends` | `<:` (deprecated)

ClassParents       ::= AnnotType {`(` [Exprs] `)`} {with AnnotType}
TraitParents       ::= AnnotType {with AnnotType}

TemplateStatSeq  ::= [id [`:` Type] `=>`] TemplateStats

TemplateStats    ::= TemplateStat {semi TemplateStat}
TemplateStat     ::= Import
                   | Annotations Modifiers Def
                   | Annotations Modifiers Dcl
                   | Expr1
                   | super ArgumentExprs {ArgumentExprs}
                   |

TmplDef ::= [case] class ClassDef
          |  [case] object ObjectDef
          |  [override] trait TraitDef

part { `sep` part }

. part { sep part } }}}

Hook for IDE, for top-level classes/objects.

TopStatSeq ::= TopStat {semi TopStat}
TopStat ::= Annotations Modifiers TmplDef
          | Packaging
          | package object ObjectDef
          | Import
          |

These are default entry points into the pattern context sensitive methods: they are all initiated from non-pattern context.

TypeBounds ::= [`>:` Type] [`<:` Type]

TypeDef ::= type Id [TypeParamClause] `=` Type
          | FunSig `=` Expr
TypeDcl ::= type Id [TypeParamClause] TypeBounds

TypeParamClauseOpt    ::= [TypeParamClause]
TypeParamClause       ::= `[` VariantTypeParam {`,` VariantTypeParam} `]`]
VariantTypeParam      ::= {Annotation} [`+` | `-`] TypeParam
FunTypeParamClauseOpt ::= [FunTypeParamClause]
FunTypeParamClause    ::= `[` TypeParam {`,` TypeParam} `]`]
TypeParam             ::= Id TypeParamClauseOpt TypeBounds {`<%` Type} {`:` Type}

TypedOpt ::= [`:` Type]

WildcardType ::= `_` TypeBounds

For use from xml pattern, where sequence is allowed and encouraged.

Modes for infix types.