27 lines
502 B
Go
27 lines
502 B
Go
|
package main
|
||
|
|
|
||
|
|
// Simple lexem stack implementation.
|
||
|
|
|
||
|
|
import "github.com/neonxp/unilex"
|
||
|
|
|
||
|
|
type lexemStack []unilex.Lexem
|
||
|
|
|
||
|
|
func (ls *lexemStack) Head() (l unilex.Lexem) {
|
||
|
|
if len(*ls) == 0 {
|
||
|
|
return unilex.Lexem{Type: unilex.LEOF}
|
||
|
|
}
|
||
|
|
return (*ls)[len(*ls)-1]
|
||
|
|
}
|
||
|
|
|
||
|
|
func (ls *lexemStack) Push(l unilex.Lexem) {
|
||
|
|
*ls = append(*ls, l)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (ls *lexemStack) Pop() (l unilex.Lexem) {
|
||
|
|
if len(*ls) == 0 {
|
||
|
|
return unilex.Lexem{Type: unilex.LEOF}
|
||
|
|
}
|
||
|
|
*ls, l = (*ls)[:len(*ls)-1], (*ls)[len(*ls)-1]
|
||
|
|
return l
|
||
|
|
}
|