mirror of
https://github.com/astaxie/beego.git
synced 2024-11-25 14:30:54 +00:00
47 lines
1.2 KiB
Go
47 lines
1.2 KiB
Go
package govaluate
|
|
|
|
import (
|
|
"bytes"
|
|
)
|
|
|
|
/*
|
|
Holds a series of "transactions" which represent each token as it is output by an outputter (such as ToSQLQuery()).
|
|
Some outputs (such as SQL) require a function call or non-c-like syntax to represent an expression.
|
|
To accomplish this, this struct keeps track of each translated token as it is output, and can return and rollback those transactions.
|
|
*/
|
|
type expressionOutputStream struct {
|
|
transactions []string
|
|
}
|
|
|
|
func (this *expressionOutputStream) add(transaction string) {
|
|
this.transactions = append(this.transactions, transaction)
|
|
}
|
|
|
|
func (this *expressionOutputStream) rollback() string {
|
|
|
|
index := len(this.transactions) - 1
|
|
ret := this.transactions[index]
|
|
|
|
this.transactions = this.transactions[:index]
|
|
return ret
|
|
}
|
|
|
|
func (this *expressionOutputStream) createString(delimiter string) string {
|
|
|
|
var retBuffer bytes.Buffer
|
|
var transaction string
|
|
|
|
penultimate := len(this.transactions) - 1
|
|
|
|
for i := 0; i < penultimate; i++ {
|
|
|
|
transaction = this.transactions[i]
|
|
|
|
retBuffer.WriteString(transaction)
|
|
retBuffer.WriteString(delimiter)
|
|
}
|
|
retBuffer.WriteString(this.transactions[penultimate])
|
|
|
|
return retBuffer.String()
|
|
}
|