forked from ulule/loukoum
/
operator.go
75 lines (59 loc) · 1.91 KB
/
operator.go
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package stmt
import (
"github.com/ulule/loukoum/types"
)
// Operator are used to compose expressions.
type Operator interface {
Statement
operator()
}
// LogicalOperator are used to evaluate two expressions using a logical operator.
type LogicalOperator struct {
Operator types.LogicalOperator
}
// NewAndOperator returns a new AND LogicalOperator instance.
func NewAndOperator() LogicalOperator {
return NewLogicalOperator(types.And)
}
// NewOrOperator returns a new OR LogicalOperator instance.
func NewOrOperator() LogicalOperator {
return NewLogicalOperator(types.Or)
}
// NewLogicalOperator returns a new LogicalOperator instance.
func NewLogicalOperator(operator types.LogicalOperator) LogicalOperator {
return LogicalOperator{
Operator: operator,
}
}
func (LogicalOperator) operator() {}
// Write exposes statement as a SQL query.
func (operator LogicalOperator) Write(ctx *types.Context) {
ctx.Write(operator.Operator.String())
}
// IsEmpty returns true if statement is undefined.
func (operator LogicalOperator) IsEmpty() bool {
return operator.Operator == ""
}
// Ensure that LogicalOperator is an Operator
var _ Operator = LogicalOperator{}
// ComparisonOperator are used to evaluate two expressions using a comparison operator.
type ComparisonOperator struct {
Operator types.ComparisonOperator
}
// NewComparisonOperator returns a new ComparisonOperator instance.
func NewComparisonOperator(operator types.ComparisonOperator) ComparisonOperator {
return ComparisonOperator{
Operator: operator,
}
}
func (ComparisonOperator) operator() {}
// Write exposes statement as a SQL query.
func (operator ComparisonOperator) Write(ctx *types.Context) {
ctx.Write(operator.Operator.String())
}
// IsEmpty returns true if statement is undefined.
func (operator ComparisonOperator) IsEmpty() bool {
return operator.Operator == ""
}
// Ensure that ComparisonOperator is an Operator
var _ Operator = ComparisonOperator{}