lua-lpeg表达式在两个delimeters之间不sub

Question

如果字符串不在某个起始和结束分隔符之间，我想了解如何使用lpeg来替换字符串。下面是一个示例，我想使用SKIPstart和SKIPstop来表示不应该替换文本的位置。

rep
rep
SKIPstart
rep
rep
SKIPstop
rep
rep

至

new
new
SKIPstart
rep
rep
SKIPstop
new
new

下面是另一个具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

和嵌套

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

对不起，我不知道lpeg，但您的任务很容易用通常的Lua模式解决
IMO、lpeg或其他外部regex库在大多数情况下都是过度使用的，Lua模式非常好。

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", "%02")
:gsub("%b12", "%0")
:gsub("(%Z*)%z?(%Z*)%z?",
function(a, b) return a:gsub("rep", "new")..b:gsub("[12]", "") 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 Skcriptunoff的答案是用标准的lua模式来实现目标的一种很好的方法。我同意，如果一个简单的方法可以工作，我不会建议使用LPeg或其他外部库。

当你问到LPeg时，我将向你展示如何使用LPeg。

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)