Lexer = {p=1,src="",line=0,code=true,list={},tmp="",err=false,errors="",keyword={i_null="null",i_true="true",i_false="false",i_s="s",i_ss="ss",i_sss="sss",i_f="f",i_else="else",i_w="w",i_t="t",i_for="for",i_fn="fn",i_end="end",i_goto="goto",i_endcode="endcode",i_return="return"}}
function Lexer:new(str)
self.src = str
return self
end
先创个lua文件，p是字符串指针、src是字符串、line表示当前行、list用来保存每行代码(出错时用来提示)、err是错误判断、errors用来保存错误信息、keyword是关键字列表。其它的信息暂时不讲。用处不大
然后function Lexer:new用来初始化。
再写个run方法函数用于开始词法解析
下面是具体代码，有一定lua基础的人应该能看懂
function Lexer:run()
local result,code = {},true
while code do
local token = Lexer:next()
if Lexer.errors ~= "" then return Lexer.errors,Lexer.list,true end
if token == nil then return result,Lexer.list,false end
result[#result+1] = token
end
return result,Lexer.list,false
end
上面代码具体意思是说，用while循环获取整个token(上偏文章说的{"KEYWORD","s",1}数据)，而Lexer:next()用来获取下个token table(表)
现在看看Lexer:next()整个代码(由于是直接发全部代码，可能比较长。可以从后面向上看。)
function Lexer:next()
local ch = string.char(string.byte(Lexer.src,Lexer.p))
if ch == nil or ch == "" then return nil end
local t,v,l,lines
--换行解析
if ch == "\x0a" then
t = "LINE" v = ch l = Lexer.line
Lexer.line = Lexer.line + 1
--空格解析
elseif ch == "\x20" then
t = "SPACE" v = ch l = Lexer.line
--标识符解析
elseif "a" <= ch and ch <= "z" or "A" <= ch and ch <= "Z" then
local str = Lexer:Identifier()
t = "IDENTIFIER"
--判断关键字
local keyword = Lexer:Keyword(str)
if keyword then t = keyword end
v = str l = Lexer.line
--解析数字
elseif "0" <= ch and ch <= "9" then
t = "NUMBER" v = Lexer:Number() l = Lexer.line
--解析字符串
elseif ch == "\"" or ch == "'" then
local vv = Lexer.String()
t = "STRING" v = vv l = Lexer.line
lines = "\"" .. vv .. "\""
elseif ch == '+' then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析+=
if chr == "=" then t = "ADD_ASSIGN" v = ch .. chr l = Lexer.line
--解析++
elseif chr == "+" then t = "INCREMENT" v = ch .. chr l = Lexer.line
--解析+
else Lexer.p = Lexer.p - 1 t = "PLUS" v = ch l = Lexer.line end
elseif ch == "-" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析-=
if chr == "=" then t = "SUBTRACT_ASSIGN" v = ch .. chr l = Lexer.line
--解析--
elseif chr == "-" then t = "DECREMENT" v = ch .. chr l = Lexer.line
--解析-
else Lexer.p = Lexer.p - 1 t = "MINUS" v = ch l = Lexer.line end
elseif ch == "*" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析*指针
if "a" <= chr and chr <= "z" or "A" <= chr and chr <= "Z" then t = "POINTER" v = Lexer:Identifier() l = Lexer.line
--解析*=
elseif chr == "=" then t = "MULTIPLY_ASSIGN" v = ch .. chr l = Lexer.line
--解析*
else Lexer.p = Lexer.p - 1 t = "MULTIPLY" v = ch l = Lexer.line end
elseif ch == "/" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析/=
if chr == "=" then t = "QUOTIENT_ASSIGN" v = ch .. chr l = Lexer.line
--解析//
elseif chr == "/" then
local line,c_p,c_d,cc = Lexer.line,true,"",""
while c_p do
Lexer.p = Lexer.p + 1
cc = string.char(string.byte(Lexer.src,Lexer.p))
if cc == "\x0a" or cc == "" then Lexer.line = Lexer.line + 1 break end
c_d = c_d .. cc
end
t = "COMMENT" v = c_d l = line
--解析/* ... */
elseif chr == "*" then
local line,c_p,c_d,a,b = Lexer.line,true,"","",""
while c_p do
Lexer.p = Lexer.p + 1
a = string.char(string.byte(Lexer.src,Lexer.p))
b = string.char(string.byte(Lexer.src,Lexer.p+1))
if a == "" then Lexer.p = Lexer.p + 1 break end
if a == '*' and b == '/' then break end
if a == "\x0a" then Lexer.line = Lexer.line + 1 end
c_d = c_d .. a
end
Lexer.p = Lexer.p + 1
t = "COMMENT" v = c_d l = line
--解析/
else Lexer.p = Lexer.p - 1 t = "SLASH" v = ch l = Lexer.line end
elseif ch == "%" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析%=
if chr == "=" then t = "REMAINDER_ASSIGN" v = ch .. chr l = Lexer.line
--解析%
else Lexer.p = Lexer.p - 1 t = "REMAINDER" v = ch l = Lexer.line end
elseif ch == "&" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析&指针
if "a" <= chr and chr <= "z" or "A" <= chr and chr <= "Z" then t = "QUOTE" v = Lexer:Identifier() l = Lexer.line
--解析&^
elseif chr == "^" then t = "AND_NOT" v = ch .. chr l = Lexer.line
--解析&=
elseif chr == "=" then t = "AND_ASSIGN" v = ch .. chr l = Lexer.line
--解析&&
elseif chr == "&" then t = "LOGICAL_AND" v = ch .. chr l = Lexer.line
--解析&
else Lexer.p = Lexer.p - 1 t = "AND" v = ch l = Lexer.line end
elseif ch == "|" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析|=
if chr == "=" then t = "OR_ASSIGN" v = ch .. chr l = Lexer.line
--解析||
elseif chr == "|" then t = "LOGICAL_OR" v = ch .. chr l = Lexer.line
--解析|
else Lexer.p = Lexer.p - 1 t = "OR" v = ch l = Lexer.line end
elseif ch == "^" then t = "EXCLUSIVE_OR" v = ch l = Lexer.line
elseif ch == "=" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析==
if chr == "=" then
Lexer.p = Lexer.p + 1
local chrs = string.char(string.byte(Lexer.src,Lexer.p))
--解析===
if chrs == "=" then t = "STRICT_EQUAL" v = ch .. chr .. chrs l = Lexer.line
--解析==
else Lexer.p = Lexer.p - 1 t = "EQUAL" v = ch .. chr l = Lexer.line end
--解析=
else Lexer.p = Lexer.p - 1 t = "ASSIGN" v = ch l = Lexer.line end
elseif ch == "<" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析<=
if chr == "=" then t = "LESS_OR_EQUAL" v = ch .. chr l = Lexer.line
--解析<<
elseif chr == "<" then t = "SHIFT_LEFT" v = ch .. chr l = Lexer.line
--解析<
else Lexer.p = Lexer.p - 1 t = "LESS" v = ch l = Lexer.line end
elseif ch == ">" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析>=
if chr == "=" then t = "GREATER_OR_EQUAL" v = ch .. chr l = Lexer.line
--解析>>
elseif chr == ">" then t = "SHIFT_RIGHT" v = ch .. chr l = Lexer.line
--解析>
else Lexer.p = Lexer.p - 1 t = "GREATER" v = ch l = Lexer.line end
elseif ch == "!" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析!=
if chr == "=" then
Lexer.p = Lexer.p + 1
local chrs = string.char(string.byte(Lexer.src,Lexer.p))
--解析!==
if chrs == "=" then t = "STRICT_NOT_EQUAL" v = ch .. chr .. chrs l = Lexer.line
--解析!=
else Lexer.p = Lexer.p - 1 t = "NOT_EQUAL" v = ch .. chr l = Lexer.line end
--解析!
else Lexer.p = Lexer.p - 1 t = "NOT" v = ch l = Lexer.line end
--解析~
elseif ch == "~" then t = "BITWISE_NOT" v = ch l = Lexer.line
--解析(
elseif ch == "(" then t = "LEFT_PARENTHESIS" v = ch l = Lexer.line
--解析[
elseif ch == "[" then t = "LEFT_BRACKET" v = ch l = Lexer.line
--解析{
elseif ch == "{" then t = "LEFT_BRACE" v = ch l = Lexer.line
--解析)
elseif ch == ")" then t = "RIGHT_PARENTHESIS" v = ch l = Lexer.line
--解析]
elseif ch == "]" then t = "RIGHT_BRACKET" v = ch l = Lexer.line
--解析}
elseif ch == "}" then t = "RIGHT_BRACE" v = ch l = Lexer.line
--解析,
elseif ch == "," then t = "COMMA" v = ch l = Lexer.line
elseif ch == "." then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析..
if chr == "." then t = "CONCAT" v = ch .. chr l = Lexer.line
--解析.
else Lexer.p = Lexer.p - 1 t = "PERIOD" v = ch l = Lexer.line end
--解析;
elseif ch == ";" then t = "SEMICOLON" v = ch l = Lexer.line
--解析:
elseif ch == ":" then t = "COLON" v = ch l = Lexer.line
--解析?
elseif ch == "?" then t = "QUESTION_MARK" v = ch l = Lexer.line
else
if Lexer.err == true and ch ~= "" then Lexer.errors = "词法分析错误:在第" .. Lexer.line .. "行,error数据[" .. ch .. "],具体代码--->" .. Lexer.list[Lexer.line] .. Lexer:Line() return nil end
end
Lexer.err = true
Lexer.p = Lexer.p + 1
--存储每行代码
if lines then str = lines else str = v end
if Lexer.list[l] == nil then Lexer.list[l] = "" end
Lexer.list[l] = Lexer.list[l] .. str
return {token=t,value=v,line=l}
end
附辅助函数:
--解析一行
function Lexer:Line()
local result = ""
while true do
local chr = string.char(string.byte(Lexer.src,Lexer.p))
if chr == "\x0a" or chr == "" then return result
else result = result .. chr Lexer.p = Lexer.p + 1 end
end
end
--整体标识符解析
function Lexer:Identifier()
local result = ""
local code = true
while code do
local chr = string.char(string.byte(Lexer.src,Lexer.p))
if chr == nil or chr == "" then code = false break end
if ("a" <= chr and chr <= "z") or ("A" <= chr and chr <= "Z") or ("0" <= chr and chr <= "9") then
result = result .. chr
Lexer.p = Lexer.p + 1
else
code = false
end
end
Lexer.p = Lexer.p - 1
return result
end
--判断关键字
function Lexer:Keyword(str)
local keyword = Lexer.keyword
for key,value in pairs(keyword) do
if value == str then
return key
end
end
return false
end
--解析字符串
function Lexer.String()
local p = string.char(string.byte(Lexer.src,Lexer.p))
Lexer.p = Lexer.p + 1
local result = ""
local code = true
while code do
local chr = string.char(string.byte(Lexer.src,Lexer.p))
if chr == "\x0a" then Lexer.line = Lexer.line + 1 end
if chr == "" then break end
if chr ~= p then
result = result .. chr
Lexer.p = Lexer.p + 1
else
code = false;
end
end
return result
end
--整体数字解析
function Lexer:Number()
local result = ""
local code = true
while code do
local chr = string.char(string.byte(Lexer.src,Lexer.p))
if chr == nil or chr == "" then code = false break end
if "0" <= chr and chr <= "9" then
result = result .. chr
Lexer.p = Lexer.p + 1
else
code = false
end
end
Lexer.p = Lexer.p - 1
return result
end
lexer.lua文件全部代码:
Lexer = {p=1,src="",line=0,code=true,list={},tmp="",err=false,errors="",keyword={i_null="null",i_true="true",i_false="false",i_s="s",i_ss="ss",i_sss="sss",i_f="f",i_else="else",i_w="w",i_t="t",i_for="for",i_fn="fn",i_end="end",i_goto="goto",i_endcode="endcode",i_return="return"}}
function Lexer:new(str)
self.src = str
return self
end
function Lexer:run()
local result,code = {},true
while code do
local token = Lexer:next()
if Lexer.errors ~= "" then return Lexer.errors,Lexer.list,true end
if token == nil then return result,Lexer.list,false end
result[#result+1] = token
end
return result,Lexer.list,false
end
function Lexer:next()
local ch = string.char(string.byte(Lexer.src,Lexer.p))
if ch == nil or ch == "" then return nil end
local t,v,l,lines
--换行解析
if ch == "\x0a" then
t = "LINE" v = ch l = Lexer.line
Lexer.line = Lexer.line + 1
--空格解析
elseif ch == "\x20" then
t = "SPACE" v = ch l = Lexer.line
--标识符解析
elseif "a" <= ch and ch <= "z" or "A" <= ch and ch <= "Z" then
local str = Lexer:Identifier()
t = "IDENTIFIER"
--判断关键字
local keyword = Lexer:Keyword(str)
if keyword then t = keyword end
v = str l = Lexer.line
--解析数字
elseif "0" <= ch and ch <= "9" then
t = "NUMBER" v = Lexer:Number() l = Lexer.line
--解析字符串
elseif ch == "\"" or ch == "'" then
local vv = Lexer.String()
t = "STRING" v = vv l = Lexer.line
lines = "\"" .. vv .. "\""
elseif ch == '+' then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析+=
if chr == "=" then t = "ADD_ASSIGN" v = ch .. chr l = Lexer.line
--解析++
elseif chr == "+" then t = "INCREMENT" v = ch .. chr l = Lexer.line
--解析+
else Lexer.p = Lexer.p - 1 t = "PLUS" v = ch l = Lexer.line end
elseif ch == "-" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析-=
if chr == "=" then t = "SUBTRACT_ASSIGN" v = ch .. chr l = Lexer.line
--解析--
elseif chr == "-" then t = "DECREMENT" v = ch .. chr l = Lexer.line
--解析-
else Lexer.p = Lexer.p - 1 t = "MINUS" v = ch l = Lexer.line end
elseif ch == "*" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析*指针
if "a" <= chr and chr <= "z" or "A" <= chr and chr <= "Z" then t = "POINTER" v = Lexer:Identifier() l = Lexer.line
--解析*=
elseif chr == "=" then t = "MULTIPLY_ASSIGN" v = ch .. chr l = Lexer.line
--解析*
else Lexer.p = Lexer.p - 1 t = "MULTIPLY" v = ch l = Lexer.line end
elseif ch == "/" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析/=
if chr == "=" then t = "QUOTIENT_ASSIGN" v = ch .. chr l = Lexer.line
--解析//
elseif chr == "/" then
local line,c_p,c_d,cc = Lexer.line,true,"",""
while c_p do
Lexer.p = Lexer.p + 1
cc = string.char(string.byte(Lexer.src,Lexer.p))
if cc == "\x0a" or cc == "" then Lexer.line = Lexer.line + 1 break end
c_d = c_d .. cc
end
t = "COMMENT" v = c_d l = line
--解析/* ... */
elseif chr == "*" then
local line,c_p,c_d,a,b = Lexer.line,true,"","",""
while c_p do
Lexer.p = Lexer.p + 1
a = string.char(string.byte(Lexer.src,Lexer.p))
b = string.char(string.byte(Lexer.src,Lexer.p+1))
if a == "" then Lexer.p = Lexer.p + 1 break end
if a == '*' and b == '/' then break end
if a == "\x0a" then Lexer.line = Lexer.line + 1 end
c_d = c_d .. a
end
Lexer.p = Lexer.p + 1
t = "COMMENT" v = c_d l = line
--解析/
else Lexer.p = Lexer.p - 1 t = "SLASH" v = ch l = Lexer.line end
elseif ch == "%" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析%=
if chr == "=" then t = "REMAINDER_ASSIGN" v = ch .. chr l = Lexer.line
--解析%
else Lexer.p = Lexer.p - 1 t = "REMAINDER" v = ch l = Lexer.line end
elseif ch == "&" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析&指针
if "a" <= chr and chr <= "z" or "A" <= chr and chr <= "Z" then t = "QUOTE" v = Lexer:Identifier() l = Lexer.line
--解析&^
elseif chr == "^" then t = "AND_NOT" v = ch .. chr l = Lexer.line
--解析&=
elseif chr == "=" then t = "AND_ASSIGN" v = ch .. chr l = Lexer.line
--解析&&
elseif chr == "&" then t = "LOGICAL_AND" v = ch .. chr l = Lexer.line
--解析&
else Lexer.p = Lexer.p - 1 t = "AND" v = ch l = Lexer.line end
elseif ch == "|" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析|=
if chr == "=" then t = "OR_ASSIGN" v = ch .. chr l = Lexer.line
--解析||
elseif chr == "|" then t = "LOGICAL_OR" v = ch .. chr l = Lexer.line
--解析|
else Lexer.p = Lexer.p - 1 t = "OR" v = ch l = Lexer.line end
elseif ch == "^" then t = "EXCLUSIVE_OR" v = ch l = Lexer.line
elseif ch == "=" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析==
if chr == "=" then
Lexer.p = Lexer.p + 1
local chrs = string.char(string.byte(Lexer.src,Lexer.p))
--解析===
if chrs == "=" then t = "STRICT_EQUAL" v = ch .. chr .. chrs l = Lexer.line
--解析==
else Lexer.p = Lexer.p - 1 t = "EQUAL" v = ch .. chr l = Lexer.line end
--解析=
else Lexer.p = Lexer.p - 1 t = "ASSIGN" v = ch l = Lexer.line end
elseif ch == "<" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析<=
if chr == "=" then t = "LESS_OR_EQUAL" v = ch .. chr l = Lexer.line
--解析<<
elseif chr == "<" then t = "SHIFT_LEFT" v = ch .. chr l = Lexer.line
--解析<
else Lexer.p = Lexer.p - 1 t = "LESS" v = ch l = Lexer.line end
elseif ch == ">" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析>=
if chr == "=" then t = "GREATER_OR_EQUAL" v = ch .. chr l = Lexer.line
--解析>>
elseif chr == ">" then t = "SHIFT_RIGHT" v = ch .. chr l = Lexer.line
--解析>
else Lexer.p = Lexer.p - 1 t = "GREATER" v = ch l = Lexer.line end
elseif ch == "!" then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析!=
if chr == "=" then
Lexer.p = Lexer.p + 1
local chrs = string.char(string.byte(Lexer.src,Lexer.p))
--解析!==
if chrs == "=" then t = "STRICT_NOT_EQUAL" v = ch .. chr .. chrs l = Lexer.line
--解析!=
else Lexer.p = Lexer.p - 1 t = "NOT_EQUAL" v = ch .. chr l = Lexer.line end
--解析!
else Lexer.p = Lexer.p - 1 t = "NOT" v = ch l = Lexer.line end
--解析~
elseif ch == "~" then t = "BITWISE_NOT" v = ch l = Lexer.line
--解析(
elseif ch == "(" then t = "LEFT_PARENTHESIS" v = ch l = Lexer.line
--解析[
elseif ch == "[" then t = "LEFT_BRACKET" v = ch l = Lexer.line
--解析{
elseif ch == "{" then t = "LEFT_BRACE" v = ch l = Lexer.line
--解析)
elseif ch == ")" then t = "RIGHT_PARENTHESIS" v = ch l = Lexer.line
--解析]
elseif ch == "]" then t = "RIGHT_BRACKET" v = ch l = Lexer.line
--解析}
elseif ch == "}" then t = "RIGHT_BRACE" v = ch l = Lexer.line
--解析,
elseif ch == "," then t = "COMMA" v = ch l = Lexer.line
elseif ch == "." then
Lexer.p = Lexer.p + 1
local chr = string.char(string.byte(Lexer.src,Lexer.p))
--解析..
if chr == "." then t = "CONCAT" v = ch .. chr l = Lexer.line
--解析.
else Lexer.p = Lexer.p - 1 t = "PERIOD" v = ch l = Lexer.line end
--解析;
elseif ch == ";" then t = "SEMICOLON" v = ch l = Lexer.line
--解析:
elseif ch == ":" then t = "COLON" v = ch l = Lexer.line
--解析?
elseif ch == "?" then t = "QUESTION_MARK" v = ch l = Lexer.line
else
if Lexer.err == true and ch ~= "" then Lexer.errors = "词法分析错误:在第" .. Lexer.line .. "行,error数据[" .. ch .. "],具体代码--->" .. Lexer.list[Lexer.line] .. Lexer:Line() return nil end
end
Lexer.err = true
Lexer.p = Lexer.p + 1
--存储每行代码
if lines then str = lines else str = v end
if Lexer.list[l] == nil then Lexer.list[l] = "" end
Lexer.list[l] = Lexer.list[l] .. str
return {token=t,value=v,line=l}
end
--解析一行
function Lexer:Line()
local result = ""
while true do
local chr = string.char(string.byte(Lexer.src,Lexer.p))
if chr == "\x0a" or chr == "" then return result
else result = result .. chr Lexer.p = Lexer.p + 1 end
end
end
--整体标识符解析
function Lexer:Identifier()
local result = ""
local code = true
while code do
local chr = string.char(string.byte(Lexer.src,Lexer.p))
if chr == nil or chr == "" then code = false break end
if ("a" <= chr and chr <= "z") or ("A" <= chr and chr <= "Z") or ("0" <= chr and chr <= "9") then
result = result .. chr
Lexer.p = Lexer.p + 1
else
code = false
end
end
Lexer.p = Lexer.p - 1
return result
end
--判断关键字
function Lexer:Keyword(str)
local keyword = Lexer.keyword
for key,value in pairs(keyword) do
if value == str then
return key
end
end
return false
end
--解析字符串
function Lexer.String()
local p = string.char(string.byte(Lexer.src,Lexer.p))
Lexer.p = Lexer.p + 1
local result = ""
local code = true
while code do
local chr = string.char(string.byte(Lexer.src,Lexer.p))
if chr == "\x0a" then Lexer.line = Lexer.line + 1 end
if chr == "" then break end
if chr ~= p then
result = result .. chr
Lexer.p = Lexer.p + 1
else
code = false;
end
end
return result
end
--整体数字解析
function Lexer:Number()
local result = ""
local code = true
while code do
local chr = string.char(string.byte(Lexer.src,Lexer.p))
if chr == nil or chr == "" then code = false break end
if "0" <= chr and chr <= "9" then
result = result .. chr
Lexer.p = Lexer.p + 1
else
code = false
end
end
Lexer.p = Lexer.p - 1
return result
end
return Lexer
(文章暂时停更，作者有空再继续讲解上面代码具体有什么用)
