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ferret/pkg/runtime/expressions/operators/math.go

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package operators
import (
"context"
"github.com/MontFerret/ferret/pkg/runtime/core"
"github.com/MontFerret/ferret/pkg/runtime/values"
)
type (
MathOperatorType string
MathOperator struct {
*baseOperator
opType MathOperatorType
fn OperatorFunc
leftOnly bool
}
)
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const (
MathOperatorTypeAdd MathOperatorType = "+"
MathOperatorTypeSubtract MathOperatorType = "-"
MathOperatorTypeMultiply MathOperatorType = "*"
MathOperatorTypeDivide MathOperatorType = "/"
MathOperatorTypeModulus MathOperatorType = "%"
MathOperatorTypeIncrement MathOperatorType = "++"
MathOperatorTypeDecrement MathOperatorType = "--"
)
var mathOperators = map[MathOperatorType]OperatorFunc{
MathOperatorTypeAdd: Add,
MathOperatorTypeSubtract: Subtract,
MathOperatorTypeMultiply: Multiply,
MathOperatorTypeDivide: Divide,
MathOperatorTypeModulus: Modulus,
MathOperatorTypeIncrement: Increment,
MathOperatorTypeDecrement: Decrement,
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}
func NewMathOperator(
src core.SourceMap,
left core.Expression,
right core.Expression,
operator MathOperatorType,
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) (*MathOperator, error) {
fn, exists := mathOperators[operator]
if !exists {
return nil, core.Error(core.ErrInvalidArgument, "operator type")
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}
var leftOnly bool
if operator == "++" || operator == "--" {
leftOnly = true
}
return &MathOperator{
&baseOperator{src, left, right},
operator,
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fn,
leftOnly,
}, nil
}
func (operator *MathOperator) Type() MathOperatorType {
return operator.opType
}
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func (operator *MathOperator) Exec(ctx context.Context, scope *core.Scope) (core.Value, error) {
left, err := operator.left.Exec(ctx, scope)
if err != nil {
return nil, err
}
if operator.leftOnly {
return operator.Eval(ctx, left, values.None)
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}
right, err := operator.right.Exec(ctx, scope)
if err != nil {
return nil, err
}
return operator.Eval(ctx, left, right)
}
func (operator *MathOperator) Eval(_ context.Context, left, right core.Value) (core.Value, error) {
if operator.leftOnly {
return operator.fn(left, values.None), nil
}
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return operator.fn(left, right), nil
}