ast

Documentation

Overview

package ast provides methods for constructing CEL abstract syntax nodes.

Index

• func NewCall(id int64, name string, target *expr.Expr, args []*expr.Expr) *expr.Expr
• func NewConst(id int64, value interface{}) *expr.Expr
• func NewIdent(id int64, name string) *expr.Expr
• func NewSelect(id int64, operand *expr.Expr, field string) *expr.Expr

Functions

func NewCall

func NewCall(id int64, name string, target *expr.Expr, args []*expr.Expr) *expr.Expr

Create a function call expression from the function name, optional receiver, arguments, and id.

All operators and user-defined functions are modelled as calls. For a list of built-in operators (restrictions), see the operators/operators.go file.

func NewConst

func NewConst(id int64, value interface{}) *expr.Expr

Create a constant from the primitive value with the given id.

func NewIdent

func NewIdent(id int64, name string) *expr.Expr

Create an identifier from the given name and id.

Identifiers may either refer to a property that can be filtered within the API, or unquoted text. Interpretation of an identifier is highly contextual.

Within CEL, type-checking asserts that all identifiers must be declared. To use type-checking with filters, a second processing step may be used to convert unknown identifiers to constant strings prior to the type-check. This may be desired as an algorithmic way for validating filters.

func NewSelect

func NewSelect(id int64, operand *expr.Expr, field string) *expr.Expr

Create a select field expression from the operand, field name, and id.

Selection occurs via the dot operator, but there is also an index expression which permits the selection of a field with non-identifier characters in it.