Function Rewrite

query/expr/ast.go:585–614

Rewrite recursively invokes the rewriter to replace each expression. Nodes are traversed depth-first and rewritten from leaf to root.

(r Rewriter, expr Expr)

// Rewrite recursively invokes the rewriter to replace each expression.
// Nodes are traversed depth-first and rewritten from leaf to root.
func Rewrite(r Rewriter, expr Expr) Expr {
	switch e := expr.(type) {
	case *UnaryExpr:
		e.Expr = Rewrite(r, e.Expr)

	case *BinaryExpr:
		e.LHS = Rewrite(r, e.LHS)
		e.RHS = Rewrite(r, e.RHS)

	case *Case:
		for i, cond := range e.WhenThens {
			cond.When = Rewrite(r, cond.When)
			cond.Then = Rewrite(r, cond.Then)
			e.WhenThens[i] = cond
		}
		if e.Else != nil {
			e.Else = Rewrite(r, e.Else)
		}

	case *ParenExpr:
		e.Expr = Rewrite(r, e.Expr)

	case *Call:
		for i, expr := range e.Args {
			e.Args[i] = Rewrite(r, expr)
		}
	}

	return r.Rewrite(expr)
}

// RewriteFunc rewrites an expression hierarchy.
func RewriteFunc(e Expr, fn func(Expr) Expr) Expr {