旧文本模板
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旧文本模板 |
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template 的函数用于创建模板，以及另一个名为 fillin 的函数，它从表中获取值并将其替换到模板中对应的位置。模板语法非常简单。表成员和全局变量通过用 | 括起来的名称引用，环境变量以 $ 为前缀，函数调用以 @ 为前缀，Lua 代码用 @{ 和 } 括起来。以下是如何使用 template 和 fillin 的示例。
require'temp.lua'
t1 = template[[
==============================================================================
you can access variables: |v|
or environment variables: $HOME
you can call functions: @concat( list, ', ' )
this list has |list.n| elements
@strrep( '=', list.n )
@concat( list )
@strrep( '=', list.n )
or evaluate code inline
@{ for i=1,4 do OUT = OUT .." list[".. i .."] = ".. list[i] .."\n" end }
you can access global variables:
This example is from |mjd| at |mjdweb|
@{ x = getn(list) }The Lord High Chamberlain has gotten @getn(list)
things for me this year.
@{ diff = x - 2
more = 'more'
if diff == 0 then
diff = 'no'
elseif diff < 0 then
more = 'fewer'
end
}
That is |diff| |more| than he gave me last year.
values can have other variables: |ref|
==============================================================================
]]
mjd = "Mark J. Dominus"
mjdweb = 'http://perl.plover.com/'
L = {}
for i = 1,5 do tinsert( L, strchar(64+i) ) end
x = {
v = 'this is v',
list = L,
ref = "|mjd| made Text::Template.pm"
}
-- fill in the template t1 with values in table x
write( fillin( x, t1 ) )
temp.lua 的代码很长，所以我把它放在另一个页面上，并附带行号。 文本模板代码 请注意，此代码需要 Lua 4.1（beta）。template 函数会从模板字符串中删除所有函数调用和 Lua 代码，并用 Magic 全局变量的名称替换它们。对于上面的示例，这就是 template 返回的内容。
==============================================================================
you can access variables: |v|
or environment variables: /home/administrator
you can call functions: |2concat|
this list has |1list| elements
|3strrep|
|4concat|
|5strrep|
or evaluate code inline
|7ANY|
you can access global variables:
This example is from |mjd| at |mjdweb|
|8ANY|The Lord High Chamberlain has gotten |6getn|
things for me this year.
|9ANY|
That is |diff| |more| than he gave me last year.
values can have other variables: |ref|
==============================================================================
template 还会将它从模板字符串中删除的所有函数调用和 Lua 代码包装在一个表中，该表以 Magic 变量名称为索引，并将所有 Magic 变量指向该表。对于上面的示例，以下是 template 生成的代码，并使用 dostring 进行评估。
local Magic = settype( {}, newtype'magic' )
Magic['1list'] = function()
local self=globals()
return list.n --
end
setglobal('1list', Magic )
Magic['2concat'] = function()
local self=globals()
return concat( list, ', ' ) --
end
setglobal('2concat', Magic )
Magic['3strrep'] = function()
local self=globals()
return strrep( '=', list.n ) --
end
setglobal('3strrep', Magic )
Magic['4concat'] = function()
local self=globals()
return concat( list ) --
end
setglobal('4concat', Magic )
Magic['5strrep'] = function()
local self=globals()
return strrep( '=', list.n ) --
end
setglobal('5strrep', Magic )
Magic['6getn'] = function()
local self=globals()
return getn(list) --
end
setglobal('6getn', Magic )
Magic['7ANY'] = function()
local OUT=''
local self=globals()
do for i=1,4 do OUT = OUT .." list[".. i .."] = ".. list[i] .."\n" end end
return OUT
end
setglobal('7ANY', Magic )
Magic['8ANY'] = function()
local OUT=''
local self=globals()
do x = getn(list) end
return OUT
end
setglobal('8ANY', Magic )
Magic['9ANY'] = function()
local OUT=''
local self=globals()
do diff = x - 2
more = 'more'
if diff == 0 then
diff = 'no'
elseif diff < 0 then
more = 'fewer'
end
end
return OUT
end
setglobal('9ANY', Magic )
fillin 函数接受一个值表和从 template 返回的字符串，并使用 gsub 填充这些值。在此之前，它将值表设置为全局变量表，并为 nil 值设置 getglobal 标签方法。因此，如果在值表中找不到变量，它会尝试在 sharedvars 表中查找，如果失败，则会查找真正的全局变量表。这看起来过于复杂，但它允许模板中的代码片段访问值表和全局变量，就像它们在作用域内一样。它还会调用与它找到的任何 Magic 变量关联的函数。如果有更好的方法，请修复此问题。