checker

Documentation

Overview

Package checker defines functions to type-checked a parsed expression against a set of identifier and function declarations.

Index

• func Check(parsedExpr *exprpb.ParsedExpr, source common.Source, env *Env) (*exprpb.CheckedExpr, *common.Errors)
• func FormatCheckedType(t *exprpb.Type) string
• func Print(e *exprpb.Expr, checks *exprpb.CheckedExpr) string
• func StandardDeclarations() []*exprpb.Decl
• type Env
  • func NewEnv(packager packages.Packager, provider ref.TypeProvider) *Env
  • func NewStandardEnv(packager packages.Packager, provider ref.TypeProvider) *Env
  • func (e *Env) Add(decls ...*exprpb.Decl) error
  • func (e *Env) EnableDynamicAggregateLiterals(enabled bool) *Env
  • func (e *Env) LookupFunction(typeName string) *exprpb.Decl
  • func (e *Env) LookupIdent(typeName string) *exprpb.Decl

Functions

func Check

func Check(parsedExpr *exprpb.ParsedExpr,
	source common.Source,
	env *Env) (*exprpb.CheckedExpr, *common.Errors)

Check performs type checking, giving a typed AST. The input is a ParsedExpr proto and an env which encapsulates type binding of variables, declarations of built-in functions, descriptions of protocol buffers, and a registry for errors. Returns a CheckedExpr proto, which might not be usable if there are errors in the error registry.

func FormatCheckedType

func FormatCheckedType(t *exprpb.Type) string

FormatCheckedType converts a type message into a string representation.

func Print

func Print(e *exprpb.Expr, checks *exprpb.CheckedExpr) string

Print returns a string representation of the Expr message, annotated with types from the CheckedExpr. The Expr must be a sub-expression embedded in the CheckedExpr.

func StandardDeclarations

func StandardDeclarations() []*exprpb.Decl

StandardDeclarations returns the Decls for all functions and constants in the evaluator.

Types

type Env

type Env struct {
	// contains filtered or unexported fields
}

Env is the environment for type checking. It consists of a Packager, a Type Provider, declarations, and collection of errors encountered during checking.

func NewEnv

func NewEnv(packager packages.Packager, provider ref.TypeProvider) *Env

NewEnv returns a new *Env with the given parameters.

func NewStandardEnv

func NewStandardEnv(packager packages.Packager, provider ref.TypeProvider) *Env

NewStandardEnv returns a new *Env with the given params plus standard declarations.

func (*Env) Add

func (e *Env) Add(decls ...*exprpb.Decl) error

Add adds new Decl protos to the Env. Returns an error for identifier redeclarations.

func (*Env) EnableDynamicAggregateLiterals

func (e *Env) EnableDynamicAggregateLiterals(enabled bool) *Env

EnableDynamicAggregateLiterals detmerines whether list and map literals may support mixed element types at check-time. This does not preclude the presence of a dynamic list or map somewhere in the CEL evaluation process.

func (*Env) LookupFunction

func (e *Env) LookupFunction(typeName string) *exprpb.Decl

LookupFunction returns a Decl proto for typeName as a function in env. Returns nil if no such function is found in env.

func (*Env) LookupIdent

func (e *Env) LookupIdent(typeName string) *exprpb.Decl

LookupIdent returns a Decl proto for typeName as an identifier in the Env. Returns nil if no such identifier is found in the Env.