regex - lua lpeg 表达式不在分隔符之间

Question

lpeg如果字符串不在某个开始和结束分隔符之间，我想了解如何替换字符串。下面是一个示例，我想在其中使用SKIPstart并SKIPstop表示不应替换文本的位置。

rep
rep
SKIPstart
rep
rep
SKIPstop
rep
rep

至

new
new
SKIPstart
rep
rep
SKIPstop
new
new

这是另一个带有多个分隔符的示例：

rep
rep
SKIPstart
rep
rep
SKIPstop
rep
rep
SKIPstart
rep
rep
SKIPstop

至

new
new
SKIPstart
rep
rep
SKIPstop
new
new
SKIPstart
rep
rep
SKIPstop

并嵌套

rep
rep
SKIPstart
rep
SKIPstart
rep
SKIPstop
rep
SKIPstop
rep
rep

至

new
new
SKIPstart
rep
SKIPstart
rep
SKIPstop
rep
SKIPstop
new
new

Answer 1

抱歉，我不知道 lpeg，但你的任务很容易用通常的 Lua 模式解决。
在大多数情况下，IMO、lpeg 或其他外部正则表达式库都是多余的，Lua 模式已经足够好。

local s = [[
rep
rep
SKIPstart
rep
rep
SKIPstop
rep
rep
SKIPstart
rep
SKIPstart
rep
SKIPstop
rep
SKIPstop
rep
rep
]]
s = s:gsub("SKIPstart", "\1%0")
     :gsub("SKIPstop", "%0\2")
     :gsub("%b\1\2", "\0%0\0")
     :gsub("(%Z*)%z?(%Z*)%z?",
         function(a, b) return a:gsub("rep", "new")..b:gsub("[\1\2]", "") end)
print(s)

输出：

new
new
SKIPstart
rep
rep
SKIPstop
new
new
SKIPstart
rep
SKIPstart
rep
SKIPstop
rep
SKIPstop
new
new

Answer 2

Egor Skriptunoff 的回答是使用标准 lua 模式来实现目标的好方法。我同意，如果一个简单的方法可以工作，我不会推荐使用 LPeg 或其他外部库。

当您询问 LPeg 时，我将向您展示如何使用 LPeg 做到这一点。

local re = require('lpeg.re')

local defs = {
  do_rep = function(p)
    return p:gsub('rep', 'new')
  end
}

local pat = re.compile([=[--lpeg
  all <- {~ ( (!delimited . [^S]*)+ -> do_rep / delimited )* ~}
  delimited <- s (!s !e . / delimited)* e
  s <- 'SKIPstart'
  e <- 'SKIPstop'
]=], defs)

local s = [[
rep
rep
SKIPstart
rep
rep
SKIPstop
rep
rep
SKIPstart
rep
SKIPstart
rep
SKIPstop
rep
SKIPstop
rep
rep
]]

s = pat:match(s)
print(s)