Type members


object TastyBuffer
class TastyBuffer(initialSize: Int)

A byte array buffer that can be filled with bytes or natural numbers in TASTY format, and that supports reading and patching addresses represented as natural numbers.

A byte array buffer that can be filled with bytes or natural numbers in TASTY format, and that supports reading and patching addresses represented as natural numbers.

object TastyFormat

********************************************************** Notation:

********************************************************** Notation:

We use BNF notation. Terminal symbols start with at least two consecutive upper case letters. Each terminal is represented as a single byte tag. Non-terminals are mixed case. Prefixes of the form lower case letter*_ are for explanation of semantic content only, they can be dropped without changing the grammar.


LongInt = Digit* StopDigit -- big endian 2's complement, value fits in a Long w/o overflow Int = LongInt -- big endian 2's complement, fits in an Int w/o overflow Nat = LongInt -- non-negative value, fits in an Int without overflow Digit = 0 | ... | 127 StopDigit = 128 | ... | 255 -- value = digit - 128


File = Header majorVersion_Nat minorVersion_Nat experimentalVersion_Nat VersionString UUID nameTable_Length Name* Section* Header = 0x5CA1AB1F UUID = Byte*16 -- random UUID VersionString = Length UTF8-CodePoint* -- string that represents the compiler that produced the TASTy

Section = NameRef Length Bytes Length = Nat -- length of rest of entry in bytes

Name = UTF8 Length UTF8-CodePoint* QUALIFIED Length qualified_NameRef selector_NameRef -- A.B EXPANDED Length qualified_NameRef selector_NameRef -- A$$B, semantically a NameKinds.ExpandedName EXPANDPREFIX Length qualified_NameRef selector_NameRef -- A$B, prefix of expanded name, see NamedKinds.ExpandPrefixName

UNIQUE Length separator_NameRef uniqid_Nat underlying_NameRef? -- Unique name A DEFAULTGETTER Length underlying_NameRef index_Nat -- DefaultGetter$

SUPERACCESSOR Length underlying_NameRef -- super$A INLINEACCESSOR Length underlying_NameRef -- inline$A OBJECTCLASS Length underlying_NameRef -- A$ (name of the module class for module A)

SIGNED Length original_NameRef resultSig_NameRef ParamSig* -- name + signature TARGETSIGNED Length original_NameRef target_NameRef resultSig_NameRef ParamSig*

ParamSig = Int // If negative, the absolute value represents the length of a type parameter section // If positive, this is a NameRef for the fully qualified name of a term parameter.

NameRef = Nat // ordinal number of name in name table, starting from 1.

Note: Unqualified names in the name table are strings. The context decides whether a name is a type-name or a term-name. The same string can represent both.

Standard-Section: "ASTs" TopLevelStat*

TopLevelStat = PACKAGE Length Path TopLevelStat* -- package path { topLevelStats } Stat

Stat = Term ValOrDefDef TYPEDEF Length NameRef (type_Term | Template) Modifier* -- modifiers type name (= type | bounds) | modifiers class name template IMPORT Length qual_Term Selector* -- import qual selectors EXPORT Length qual_Term Selector* -- export qual selectors ValOrDefDef = VALDEF Length NameRef type_Term rhs_Term? Modifier* -- modifiers val name : type (= rhs)? DEFDEF Length NameRef Param* returnType_Term rhs_Term? Modifier* -- modifiers def name [typeparams] paramss : returnType (= rhs)? Selector = IMPORTED name_NameRef -- name, "_" for normal wildcards, "" for given wildcards RENAMED to_NameRef -- => name BOUNDED type_Term -- type bound

TypeParam = TYPEPARAM Length NameRef type_Term Modifier* -- modifiers name bounds TermParam = PARAM Length NameRef type_Term rhs_Term? Modifier* -- modifiers name : type (= rhs_Term)?. rhsTerm is present in the case of an aliased class parameter EMPTYCLAUSE -- an empty parameter clause () SPLITCLAUSE -- splits two non-empty parameter clauses of the same kind Param = TypeParam TermParam Template = TEMPLATE Length TypeParam* TermParam* parent_Term* Self? Stat* -- [typeparams] paramss extends parents { self => stats }, where Stat* always starts with the primary constructor. Self = SELFDEF selfName_NameRef selfType_Term -- selfName : selfType

Term = Path -- Paths represent both types and terms IDENT NameRef Type -- Used when term ident’s type is not a TermRef SELECT possiblySigned_NameRef qual_Term -- SELECTin Length possiblySigned_NameRef qual_Term owner_Type --, referring to a symbol declared in owner that has the given signature (see note below) QUALTHIS typeIdent_Tree -- id.this, different from THIS in that it contains a qualifier ident with position. NEW clsType_Term -- new cls THROW throwableExpr_Term -- throw throwableExpr NAMEDARG paramName_NameRef arg_Term -- paramName = arg APPLY Length fn_Term arg_Term* -- fn(args) TYPEAPPLY Length fn_Term arg_Type* -- fn[args] SUPER Length this_Term mixinTypeIdent_Tree? -- super[mixin] TYPED Length expr_Term ascriptionType_Term -- expr: ascription ASSIGN Length lhs_Term rhs_Term -- lhs = rhs BLOCK Length expr_Term Stat* -- { stats; expr } INLINED Length expr_Term call_Term? ValOrDefDef* -- Inlined code from call, with given body expr and given bindings LAMBDA Length meth_Term target_Type? -- Closure over method f of type target (omitted id target is a function type) IF Length [INLINE] cond_Term then_Term else_Term -- inline? if cond then thenPart else elsePart MATCH Length (IMPLICIT | [INLINE] sel_Term) CaseDef* -- (inline? sel | implicit) match caseDefs TRY Length expr_Term CaseDef* finalizer_Term? -- try expr catch {casdeDef} (finally finalizer)? RETURN Length meth_ASTRef expr_Term? -- return expr?, methASTRef is method from which is returned WHILE Length cond_Term body_Term -- while cond do body REPEATED Length elem_Type elem_Term* -- Varargs argument of type elem SELECTouter Length levels_Nat qual_Term underlying_Type -- Follow levels outer links, starting from qual, with given underlying type -- patterns: BIND Length boundName_NameRef patType_Type pat_Term -- name @ pat, wherev patType is the type of the bound symbol ALTERNATIVE Length alt_Term* -- alt1 | ... | altn as a pattern UNAPPLY Length fun_Term ImplicitArg* pat_Type pat_Term* -- Unapply node fun(_: pat_Type)(implicitArgs) flowing into patterns pat. -- type trees: IDENTtpt NameRef Type -- Used for all type idents SELECTtpt NameRef qual_Term -- SINGLETONtpt ref_Term -- ref.type REFINEDtpt Length underlying_Term refinement_Stat* -- underlying {refinements} APPLIEDtpt Length tycon_Term arg_Term* -- tycon [args] LAMBDAtpt Length TypeParam* body_Term -- [TypeParams] => body TYPEBOUNDStpt Length low_Term high_Term? -- >: low <: high ANNOTATEDtpt Length underlying_Term fullAnnotation_Term -- underlying @ annotation MATCHtpt Length bound_Term? sel_Term CaseDef* -- sel match { CaseDef } where bound is optional upper bound of all rhs BYNAMEtpt underlying_Term -- => underlying SHAREDterm term_ASTRef -- Link to previously serialized term HOLE Length idx_Nat arg_Tree* -- Hole where a splice goes with sequence number idx, splice is applied to arguments args

CaseDef = CASEDEF Length pat_Term rhs_Tree guard_Tree? -- case pat if guard => rhs ImplicitArg = IMPLICITARG arg_Term -- implicit unapply argument

ASTRef = Nat -- Byte position in AST payload

Path = Constant TERMREFdirect sym_ASTRef -- A reference to a local symbol (without a prefix). Reference is to definition node of symbol. TERMREFsymbol sym_ASTRef qual_Type -- A reference qual.sym to a local member with prefix qual TERMREFpkg fullyQualified_NameRef -- A reference to a package member with given fully qualified name TERMREF possiblySigned_NameRef qual_Type -- A reference to a non-local member TERMREFin Length possiblySigned_NameRef qual_Type owner_Type -- A reference referring to a non-local symbol declared in owner that has the given signature (see note below) THIS clsRef_Type -- cls.this RECthis recType_ASTRef -- The this in a recursive refined type recType. SHAREDtype path_ASTRef -- link to previously serialized path

Constant = UNITconst -- () FALSEconst -- false TRUEconst -- true BYTEconst Int -- A byte number SHORTconst Int -- A short number CHARconst Nat -- A character INTconst Int -- An int number LONGconst LongInt -- A long number FLOATconst Int -- A float number DOUBLEconst LongInt -- A double number STRINGconst NameRef -- A string literal NULLconst -- null CLASSconst Type -- classOf[Type]

Type = Path -- Paths represent both types and terms TYPEREFdirect sym_ASTRef -- A reference to a local symbol (without a prefix). Reference is to definition node of symbol. TYPEREFsymbol sym_ASTRef qual_Type -- A reference qual.sym to a local member with prefix qual TYPEREFpkg fullyQualified_NameRef -- A reference to a package member with given fully qualified name TYPEREF NameRef qual_Type -- A reference to a non-local member TYPEREFin Length NameRef qual_Type namespace_Type -- A reference to a non-local member that's private in namespace. RECtype parent_Type -- A wrapper for recursive refined types SUPERtype Length this_Type underlying_Type -- A super type reference to underlying REFINEDtype Length underlying_Type refinement_NameRef info_Type -- underlying { refinement_name : info } APPLIEDtype Length tycon_Type arg_Type* -- tycon[args] TYPEBOUNDS Length lowOrAlias_Type high_Type? Variance* -- = alias or >: low <: high, possibly with variances of lambda parameters ANNOTATEDtype Length underlying_Type annotation_Term -- underlying @ annotation ANDtype Length left_Type right_Type -- left & right ORtype Length left_Type right_Type -- lefgt | right MATCHtype Length bound_Type sel_Type case_Type* -- sel match {cases} with optional upper bound MATCHCASEtype Length pat_type rhs_Type -- match cases are MATCHCASEtypes or TYPELAMBDAtypes over MATCHCASEtypes BIND Length boundName_NameRef bounds_Type Modifier* -- boundName @ bounds, for type-variables defined in a type pattern BYNAMEtype underlying_Type -- => underlying PARAMtype Length binder_ASTRef paramNum_Nat -- A reference to parameter # paramNum in lambda type binder POLYtype Length result_Type TypesNames -- A polymorphic method type [TypesNames]result, used in refinements METHODtype Length result_Type TypesNames Modifier* -- A method type (Modifier* TypesNames)result, needed for refinements, with optional modifiers for the parameters TYPELAMBDAtype Length result_Type TypesNames -- A type lambda [TypesNames] => result SHAREDtype type_ASTRef -- link to previously serialized type TypesNames = TypeName* TypeName = typeOrBounds_ASTRef paramName_NameRef -- (termName: type) or (typeName bounds)

Modifier = PRIVATE -- private PROTECTED -- protected PRIVATEqualified qualifier_Type -- private[qualifier] (to be dropped(?) PROTECTEDqualified qualifier_Type -- protecred[qualifier] (to be dropped(?) ABSTRACT -- abstract FINAL -- final SEALED -- sealed CASE -- case (for classes or objects) IMPLICIT -- implicit GIVEN -- given ERASED -- erased LAZY -- lazy OVERRIDE -- override OPAQUE -- opaque, also used for classes containing opaque aliases INLINE -- inline MACRO -- Inline method containing toplevel splices INLINEPROXY -- Symbol of binding with an argument to an inline method as rhs (TODO: do we still need this?) STATIC -- Mapped to static Java member OBJECT -- An object or its class TRAIT -- A trait ENUM -- A enum class or enum case LOCAL -- private[this] or protected[this], used in conjunction with PRIVATE or PROTECTED SYNTHETIC -- Generated by Scala compiler ARTIFACT -- To be tagged Java Synthetic MUTABLE -- A var FIELDaccessor -- A getter or setter (note: the corresponding field is not serialized) CASEaccessor -- A getter for a case class parameter COVARIANT -- A type parameter marked “+” CONTRAVARIANT -- A type parameter marked “-” HASDEFAULT -- Parameter with default arg; method with default parameters (default arguments are separate methods with DEFAULTGETTER names) STABLE -- Method that is assumed to be stable, i.e. its applications are legal paths EXTENSION -- An extension method PARAMsetter -- The setter part x_= of a var parameter x which itself is pickled as a PARAM PARAMalias -- Parameter is alias of a superclass parameter EXPORTED -- An export forwarder OPEN -- an open class INVISIBLE -- invisible during typechecking Annotation

Variance = STABLE -- invariant | COVARIANT | CONTRAVARIANT

Annotation = ANNOTATION Length tycon_Type fullAnnotation_Term -- An annotation, given (class) type of constructor, and full application tree

Note: The signature of a SELECTin or TERMREFin node is the signature of the selected symbol, not the signature of the reference. The latter undergoes an asSeenFrom but the former does not.

Note: Tree tags are grouped into 5 categories that determine what follows, and thus allow to compute the size of the tagged tree in a generic way.

Category 1 (tags 1-59) : tag Category 2 (tags 60-89) : tag Nat Category 3 (tags 90-109) : tag AST Category 4 (tags 110-127): tag Nat AST Category 5 (tags 128-255): tag Length

Standard-Section: "Positions" LinesSizes Assoc*

LinesSizes = Nat Nat* // Number of lines followed by the size of each line not counting the trailing \n

Assoc = Header offset_Delta? offset_Delta? point_Delta? | SOURCE nameref_Int Header = addr_Delta + // in one Nat: difference of address to last recorded node << 3 + hasStartDiff + // one bit indicating whether there follows a start address delta << 2 hasEndDiff + // one bit indicating whether there follows an end address delta << 1 hasPoint // one bit indicating whether the new position has a point (i.e ^ position) // Nodes which have the same positions as their parents are omitted. // offset_Deltas give difference of start/end offset wrt to the // same offset in the previously recorded node (or 0 for the first recorded node) Delta = Int // Difference between consecutive offsets, SOURCE = 4 // Impossible as header, since addr_Delta = 0 implies that we refer to the // same tree as the previous one, but then hasStartDiff = 1 implies that // the tree's range starts later than the range of itself.

All elements of a position section are serialized as Ints

Standard Section: "Comments" Comment*

Comment = Length Bytes LongInt // Raw comment's bytes encoded as UTF-8, followed by the comment's coordinates.


sealed abstract case class TastyHeader(uuid: UUID, majorVersion: Int, minorVersion: Int, experimentalVersion: Int, toolingVersion: String)

The Tasty Header consists of four fields: - uuid

The Tasty Header consists of four fields: - uuid

  • contains a hash of the sections of the TASTy file - majorVersion

  • matching the TASTy format version that last broke backwards compatibility - minorVersion

  • matching the TASTy format version that last broke forward compatibility - experimentalVersion

  • 0 for final compiler version

  • positive for between minor versions and forward compatibility is broken since the previous stable version. - toolingVersion

  • arbitrary string representing the tooling that produced the TASTy

class TastyReader(val bytes: Array[Byte], start: Int, end: Int, val base: Int)

A byte array buffer that can be filled with bytes or natural numbers in TASTY format, and that supports reading and patching addresses represented as natural numbers.

A byte array buffer that can be filled with bytes or natural numbers in TASTY format, and that supports reading and patching addresses represented as natural numbers.

Value Params

The index referenced by the logical zero address Addr(0)


The array containing data


The position one greater than the last byte to be read


The position from which to read