Documentation
¶
Overview ¶
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.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( 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 LoadBindsGlobally = false // load creates global not file-local bindings (deprecated) // obsolete flags for features that are now standard. No effect. AllowNestedDef = true AllowLambda = true AllowFloat = true AllowBitwise = true )
global options These features are either not standard Starlark (yet), or deprecated features of the BUILD language, so we put them behind flags.
Deprecated: use an explicit syntax.FileOptions argument instead, as it avoids all the usual problems of global variables.
Functions ¶
func File ¶
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.
Types ¶
type Binding ¶
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 identifier. The resolver populates the Binding field of each syntax.Identifier. The Binding ties together all identifiers that denote the same variable.
func Expr ¶
Expr calls ExprOptions using syntax.LegacyFileOptions. Deprecated: relies on legacy global variables.
func ExprOptions ¶
func ExprOptions(opts *syntax.FileOptions, expr syntax.Expr, isPredeclared, isUniversal func(name string) bool) ([]*Binding, error)
ExprOptions 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 ErrorList ¶
type ErrorList []Error // len > 0
An ErrorList is a non-empty list of resolver error messages.
type Function ¶
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 ¶
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 ¶
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) )
Source Files