对正则表达式练习器的改进，原贴ID901680

覆盖原execIt函数

修改后的execIt函数允许对多个正则表达式进行匹配(每个正则表达式一行)，并对每一个匹配成分显示出是第几个正则表达式匹配的。

这可视为语法分析的雏形，只要对匹配产生相应的动作。

function execIt(form) {

var mode

if(form.chkmode.checked) mode = "gi"

else mode = "g"

var regexpArray = form.regexp.value.split("\r\n") //获取正则表达式到数组

if(nextpoint == 0) form.reglist.value = ""

var key = true

if(form.scankmode.checked) key = false

else nextpoint = 0

do {

var offs = 9999999999

var pos = -1

var input = form.main.value.substr(nextpoint)

//对每个正则表达式进行匹配

for(var i=0;i

re.compile(regexpArray[i],mode)

var matchArray = re.exec(input)

if(matchArray) {

if(offs > matchArray.index) {

offs = matchArray.index

pos = i //保存距离起始位子最近的匹配

}

}

}

if(pos>=0) {

re.compile(regexpArray[pos],mode)

var matchArray = re.exec(input)

for(var i=1;i

matchArray[i] = "$"+i+":"+matchArray[i]

form.reglist.value = "["+(pos+1)+"]"+(nextpoint+matchArray.index)+" => " + matchArray[0] +"\n"+form.reglist.value

form.matchlist.value = "$0:"+matchArray.join("\n")

nextpoint = nextpoint + matchArray.index + matchArray[0].length

}else {

if(!key)

form.reglist.value = "没有找到\n" + form.reglist.value

form.matchlist.value = " "

nextpoint = 0

key = false

}

}while(key)

}