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expr_tuplemap.go
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/
expr_tuplemap.go
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package rel
import (
"fmt"
"github.com/arr-ai/wbnf/parser"
)
// TupleMapExpr returns the tuple applied to a function.
type TupleMapExpr struct {
ExprScanner
lhs Expr
fn *Function
}
// NewAngleArrowExpr returns a new AtArrowExpr.
func NewTupleMapExpr(scanner parser.Scanner, lhs Expr, fn Expr) Expr {
return &TupleMapExpr{ExprScanner{scanner}, lhs, ExprAsFunction(fn)}
}
// LHS returns the LHS of the AtArrowExpr.
func (e *TupleMapExpr) LHS() Expr {
return e.lhs
}
// Fn returns the function to be applied to the LHS.
func (e *TupleMapExpr) Fn() *Function {
return e.fn
}
// String returns a string representation of the expression.
func (e *TupleMapExpr) String() string {
return fmt.Sprintf("(%s :> %s)", e.lhs, e.fn)
}
// Eval returns the lhs
func (e *TupleMapExpr) Eval(local Scope) (_ Value, err error) {
defer wrapPanic(e, &err, local)
value, err := e.lhs.Eval(local)
if err != nil {
return nil, wrapContext(err, e, local)
}
defer func() {
if r := recover(); r != nil {
if err == nil {
panic(r)
}
}
}()
return value.(Tuple).Map(func(v Value) Value {
scope, _ := e.fn.arg.Bind(local, v) //nolint: errcheck
v, err = e.fn.body.Eval(local.Update(scope))
if err != nil {
panic(err)
}
return v
}), nil
}