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package resolve

import "go.starlark.net/resolve"

Package resolve defines a name-resolution pass for Starlark abstract syntax trees.

The resolver sets the Locals and FreeVars arrays of each DefStmt and the LocalIndex field of each syntax.Ident that refers to a local or free variable. It also sets the Locals array of a File for locals bound by top-level comprehensions and load statements. Identifiers for global variables do not get an index.


Package Files

binding.go resolve.go


var (
    AllowNestedDef      = false // allow def statements within function bodies
    AllowLambda         = false // allow lambda expressions
    AllowFloat          = false // allow floating point literals, the 'float' built-in, and x / y
    AllowSet            = false // allow the 'set' built-in
    AllowGlobalReassign = false // allow reassignment to top-level names; also, allow if/for/while at top-level
    AllowRecursion      = false // allow while statements and recursive functions
    AllowBitwise        = true  // obsolete; bitwise operations (&, |, ^, ~, <<, and >>) are always enabled
    LoadBindsGlobally   = false // load creates global not file-local bindings (deprecated)

global options These features are either not standard Starlark (yet), or deprecated features of the BUILD language, so we put them behind flags.

func File Uses

func File(file *syntax.File, isPredeclared, isUniversal func(name string) bool) error

File resolves the specified file and records information about the module in file.Module.

The isPredeclared and isUniversal predicates report whether a name is a pre-declared identifier (visible in the current module) or a universal identifier (visible in every module). Clients should typically pass predeclared.Has for the first and starlark.Universe.Has for the second, where predeclared is the module's StringDict of predeclared names and starlark.Universe is the standard set of built-ins. The isUniverse predicate is supplied a parameter to avoid a cyclic dependency upon starlark.Universe, not because users should ever need to redefine it.

func REPLChunk Uses

func REPLChunk(file *syntax.File, isGlobal, isPredeclared, isUniversal func(name string) bool) error

REPLChunk is a generalization of the File function that supports a non-empty initial global block, as occurs in a REPL.

type Binding Uses

type Binding struct {
    Scope Scope

    // Index records the index into the enclosing
    // - {DefStmt,File}.Locals, if Scope==Local
    // - DefStmt.FreeVars,      if Scope==Free
    // - File.Globals,          if Scope==Global.
    // It is zero if Scope is Predeclared, Universal, or Undefined.
    Index int

    First *syntax.Ident // first binding use (iff Scope==Local/Free/Global)

A Binding contains resolver information about an identifer. The resolver populates the Binding field of each syntax.Identifier. The Binding ties together all identifiers that denote the same variable.

func Expr Uses

func Expr(expr syntax.Expr, isPredeclared, isUniversal func(name string) bool) ([]*Binding, error)

Expr resolves the specified expression. It returns the local variables bound within the expression.

The isPredeclared and isUniversal predicates behave as for the File function.

type Error Uses

type Error struct {
    Pos syntax.Position
    Msg string

An Error describes the nature and position of a resolver error.

func (Error) Error Uses

func (e Error) Error() string

type ErrorList Uses

type ErrorList []Error // len > 0

An ErrorList is a non-empty list of resolver error messages.

func (ErrorList) Error Uses

func (e ErrorList) Error() string

type Function Uses

type Function struct {
    Pos    syntax.Position // of DEF or LAMBDA
    Name   string          // name of def, or "lambda"
    Params []syntax.Expr   // param = ident | ident=expr | * | *ident | **ident
    Body   []syntax.Stmt   // contains synthetic 'return expr' for lambda

    HasVarargs      bool       // whether params includes *args (convenience)
    HasKwargs       bool       // whether params includes **kwargs (convenience)
    NumKwonlyParams int        // number of keyword-only optional parameters
    Locals          []*Binding // this function's local/cell variables, parameters first
    FreeVars        []*Binding // enclosing cells to capture in closure

A Function contains resolver information about a named or anonymous function. The resolver populates the Function field of each syntax.DefStmt and syntax.LambdaExpr.

type Module Uses

type Module struct {
    Locals  []*Binding // the file's (comprehension-)local variables
    Globals []*Binding // the file's global variables

A Module contains resolver information about a file. The resolver populates the Module field of each syntax.File.

type Scope Uses

type Scope uint8

The Scope of Binding indicates what kind of scope it has.

const (
    Undefined   Scope = iota // name is not defined
    Local                    // name is local to its function or file
    Cell                     // name is function-local but shared with a nested function
    Free                     // name is cell of some enclosing function
    Global                   // name is global to module
    Predeclared              // name is predeclared for this module (e.g. glob)
    Universal                // name is universal (e.g. len)

func (Scope) String Uses

func (scope Scope) String() string

Package resolve imports 6 packages (graph) and is imported by 29 packages. Updated 2020-02-01. Refresh now. Tools for package owners.