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