kubernetes/vendor/github.com/google/cel-go/cel/folding.go

type ConstantFoldingOption …

// MaxConstantFoldIterations limits the number of times literals may be folding during optimization.
//
// Defaults to 100 if not set.
func MaxConstantFoldIterations(limit int) ConstantFoldingOption { … }

// NewConstantFoldingOptimizer creates an optimizer which inlines constant scalar an aggregate
// literal values within function calls and select statements with their evaluated result.
func NewConstantFoldingOptimizer(opts ...ConstantFoldingOption) (ASTOptimizer, error) { … }

type constantFoldingOptimizer …

// Optimize queries the expression graph for scalar and aggregate literal expressions within call and
// select statements and then evaluates them and replaces the call site with the literal result.
//
// Note: only values which can be represented as literals in CEL syntax are supported.
func (opt *constantFoldingOptimizer) Optimize(ctx *OptimizerContext, a *ast.AST) *ast.AST { … }

// tryFold attempts to evaluate a sub-expression to a literal.
//
// If the evaluation succeeds, the input expr value will be modified to become a literal, otherwise
// the method will return an error.
func tryFold(ctx *OptimizerContext, a *ast.AST, expr ast.Expr) error { … }

// maybePruneBranches inspects the non-strict call expression to determine whether
// a branch can be removed. Evaluation will naturally prune logical and / or calls,
// but conditional will not be pruned cleanly, so this is one small area where the
// constant folding step reimplements a portion of the evaluator.
func maybePruneBranches(ctx *OptimizerContext, expr ast.NavigableExpr) bool { … }

func maybeShortcircuitLogic(ctx *OptimizerContext, function string, args []ast.Expr, expr ast.NavigableExpr) bool { … }

// pruneOptionalElements works from the bottom up to resolve optional elements within
// aggregate literals.
//
// Note, many aggregate literals will be resolved as arguments to functions or select
// statements, so this method exists to handle the case where the literal could not be
// fully resolved or exists outside of a call, select, or comprehension context.
func pruneOptionalElements(ctx *OptimizerContext, root ast.NavigableExpr) { … }

func pruneOptionalListElements(ctx *OptimizerContext, e ast.Expr) { … }

func pruneOptionalMapEntries(ctx *OptimizerContext, e ast.Expr) { … }

func pruneOptionalStructFields(ctx *OptimizerContext, e ast.Expr) { … }

// adaptLiteral converts a runtime CEL value to its equivalent literal expression.
//
// For strongly typed values, the type-provider will be used to reconstruct the fields
// which are present in the literal and their equivalent initialization values.
func adaptLiteral(ctx *OptimizerContext, val ref.Val) (ast.Expr, error) { … }

// constantExprMatcher matches calls, select statements, and comprehensions whose arguments
// are all constant scalar or aggregate literal values.
//
// Only comprehensions which are not nested are included as possible constant folds, and only
// if all variables referenced in the comprehension stack exist are only iteration or
// accumulation variables.
func constantExprMatcher(e ast.NavigableExpr) bool { … }

// constantCallMatcher identifies strict and non-strict calls which can be folded.
func constantCallMatcher(e ast.NavigableExpr) bool { … }

func isNestedComprehension(e ast.NavigableExpr) bool { … }

func aggregateLiteralMatcher(e ast.NavigableExpr) bool { … }

var constantMatcher …

const defaultMaxConstantFoldIterations …