模块:String

可在模块:String/doc创建此模块的帮助文档

-- 此模块引用自维基百科同名页面，引用行为依据 CC BY-SA 3.0 条款
-- 部分内容因为本地化或其他修改，可能与原模块有出入
--[[  

该模块提供了基本的字符串函数。

这里的大多数函数都能以命名参数、匿名参数或混合前两种的形式调用。
若使用命名参数，Mediawiki 将自动删除参数前后的空格符号。
是否应该删除或保留前后空格，取决于具体用途。

全局配置
    ignore_errors: 如果设为 'true' 或 1，任何出错都将返回空字符串而非报错信息。
        
    error_category: 如果发生异常，报错信息会自动添加一个分类到页面上，默认分类是  
        [Category:字符串模块报告的错误]。
        
    no_category: 如果设为 'true' 或 1，报错时不会添加分类。
        
你可以在 Module:String/tests 找到单元测试。
]]

local str = {}

--[[
len

返回目标字符串的长度。

用法:
{{#invoke:String|len|目标字符串|}}
或
{{#invoke:String|len|s=目标字符串}}

参数:
    s: 要计算长度的字符串

若使用命名参数（第二种调用方法），Mediawiki 将自动删除目标字符串前后的空格符号。
]]
function str.len( frame )
    local new_args = str._getParameters( frame.args, {'s'} );
    local s = new_args['s'] or '';
    return mw.ustring.len( s )
end

--[[
sub

根据指定索引，从目标字符串中获取子字符串

用法:
{{#invoke:String|sub|目标字符串|开始位置|结束位置}}
或
{{#invoke:String|sub|s=目标字符串|i=开始位置|j=结束位置}}

参数:
    s: 目标字符串，子字符串来自于它。
    i: 子字符串的开始位置，默认为 1。
    j: 子字符串的结束位置，默认为最后一位。
    
字符串第一个字符的索引为 1。
如果 i 或 j 传入了负数，将视为从字符串末尾开始计数的索引。
比如 -1 会视为字符串的最后一位。

如果索引位置超出字符串长度，将会报错。
]]
function str.sub( frame )
    local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } );
    local s = new_args['s'] or '';
    local i = tonumber( new_args['i'] ) or 1;
    local j = tonumber( new_args['j'] ) or -1;
    
    local len = mw.ustring.len( s );

    -- 转换负数并检查区间
    if i < 0 then
        i = len + i + 1;
    end
    if j < 0 then
        j = len + j + 1;
    end
    
    if i > len or j > len or i < 1 or j < 1 then
        return str._error( '截取字符串索引脱离区间' );
    end
    if j < i then
        return str._error( '截取字符串指示脱离顺序' );
    end
    
    return mw.ustring.sub( s, i, j )
end

--[[
This function implements that features of {{str sub old}} and is kept in order
to maintain these older templates.
]]
function str.sublength( frame )
    local i = tonumber( frame.args.i ) or 0
    local len = tonumber( frame.args.len )
    return mw.ustring.sub( frame.args.s, i + 1, len and ( i + len ) )
end

--[[
match

根据指定模式，从目标字符串中获取匹配的子字符串

用法:
{{#invoke:String|match|目标字符串|pattern_string|start_index|match_number|plain_flag|无匹配输出}}
或
{{#invoke:String|pos|s=目标字符串|pattern=pattern_string|start=start_index
    |match=match_number|plain=plain_flag|nomatch=无匹配输出}}

参数:
    s: 目标字符串，以它查找匹配
    pattern: 在目标字符串中查找用的，指定模式或字符串
    start: The index within the source string to start the search.  The first
        character of the string has index 1.  默认为 1。
    match: In some cases it may be possible to make multiple matches on a single 
        string.  This specifies which match to return, where the first match is 
        match= 1.  If a negative number is specified then a match is returned 
        counting from the last match.  Hence match = -1 is the same as requesting
        the last match.  默认为 1。
    plain: 指示 pattern 参数是否视为"字符串"的标记，默认为否（即默认视为"模式"）。
    nomatch: 如果找不到匹配项，输出 "nomatch" 的值而非报错。

若使用命名参数（第二种调用方法），Mediawiki 将自动删除参数前后的空格符号。
In some circumstances this is desirable, in other cases one may want to preserve the whitespace.

If the match_number or start_index are out of range for the string being queried, then
this function generates an error.  An error is also generated if no match is found.
If one adds the parameter ignore_errors=true, then the error will be suppressed and 
an empty string will be returned on any failure.

关于构造 Lua 匹配模式的更多信息，一种[正则表达式]，参见：

* http://www.lua.org/manual/5.1/manual.html#5.4.1
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Ustring_patterns

]]
function str.match( frame )
    local new_args = str._getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain', 'nomatch'} );
    local s = new_args['s'] or '';
    local start = tonumber( new_args['start'] ) or 1;
    local plain_flag = str._getBoolean( new_args['plain'] or false );
    local pattern = new_args['pattern'] or '';
    local match_index = math.floor( tonumber(new_args['match']) or 1 );
    local nomatch = new_args['nomatch'];
    
    if s == '' then
        return str._error( '目标字符串是空的' );
    end
    if pattern == '' then
        return str._error( '模式字符串是空的' );
    end
    if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
        return str._error( '要求的起始点脱离区间' );
    end
    if match_index == 0 then
        return str._error( '匹配索引脱离区间' );
    end
    if plain_flag then
        pattern = str._escapePattern( pattern );
    end
    
    local result
    if match_index == 1 then
        -- Find first match is simple case
        result = mw.ustring.match( s, pattern, start )
    else
        if start > 1 then
            s = mw.ustring.sub( s, start );
        end
        
        local iterator = mw.ustring.gmatch(s, pattern);
        if match_index > 0 then
            -- Forward search
            for w in iterator do
                match_index = match_index - 1;
                if match_index == 0 then
                    result = w;
                    break;
                end
            end    
        else
            -- Reverse search
            local result_table = {};
            local count = 1;
            for w in iterator do
                result_table[count] = w;
                count = count + 1;
            end
            
            result = result_table[ count + match_index ];            
        end
    end        
    
    if result == nil then
        if nomatch == nil then
            return str._error( '找不到匹配' );
        else
            return nomatch;
        end
    else
        return result;
    end
end

--[[
pos

返回目标字符串在索引位置的那个字符。

用法:
{{#invoke:String|pos|目标字符串|索引值}}
OR
{{#invoke:String|pos|target=目标字符串|pos=索引值}}

参数:
    target: 目标字符串，从它获取字符
    pos: 需要返回的字符之索引位置

If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string.  In some circumstances this is desirable, in 
other cases one may want to preserve the whitespace.

字符串第一个字符的索引为 1。

If one requests a negative value, this function will select a character by counting backwards 
from the end of the string.  In other words pos = -1 is the same as asking for the last character.

A requested value of zero, or a value greater than the length of the string returns an error.
]]
function str.pos( frame )
    local new_args = str._getParameters( frame.args, {'target', 'pos'} );
    local target_str = new_args['target'] or '';
    local pos = tonumber( new_args['pos'] ) or 0;

    if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then
        return str._error( '字符串索引脱离区间' );
    end    
    
    return mw.ustring.sub( target_str, pos, pos );
end

--[[
str_find

This function duplicates the behavior of {{str_find}}, including all of its quirks.
This is provided in order to support existing templates, but is NOT RECOMMENDED for 
new code and templates.  New code is recommended to use the "find" function instead.

Returns the first index in "source" that is a match to "target".  Indexing is 1-based,
and the function returns -1 if the "target" string is not present in "source".

Important Note: If the "target" string is empty / missing, this function returns a
value of "1", which is generally unexpected behavior, and must be accounted for
separatetly.
]]
function str.str_find( frame )
    local new_args = str._getParameters( frame.args, {'source', 'target'} );
    local source_str = new_args['source'] or '';
    local target_str = new_args['target'] or '';

    if target_str == '' then
        return 1;
    end    
    
    local start = mw.ustring.find( source_str, target_str, 1, true )
    if start == nil then
        start = -1
    end
    
    return start
end

--[[
find

This function allows one to search for a target string or pattern within another
string.

用法:
{{#invoke:String|find|source_str|target_string|start_index|plain_flag}}
OR
{{#invoke:String|find|source=source_str|target=target_str|start=start_index|plain=plain_flag}}

参数:
    source: The string to search
    target: The string or pattern to find within source
    start: The index within the source string to start the search, 默认为 1
    plain: 指示 pattern 参数是否视为"字符串"而非 Lua 风格的正则表达式的 Boolean 标记, 默认为 true。

If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the parameter.  In some circumstances this is desirable, in 
other cases one may want to preserve the whitespace.

This function returns the first index >= "start" where "target" can be found 
within "source".  Indices are 1-based.  If "target" is not found, then this 
function returns 0.  If either "source" or "target" are missing / empty, this
function also returns 0.

This function should be safe for UTF-8 strings.
]]
function str.find( frame )
    local new_args = str._getParameters( frame.args, {'source', 'target', 'start', 'plain' } ); 
    local source_str = new_args['source'] or '';
    local pattern = new_args['target'] or '';
    local start_pos = tonumber(new_args['start']) or 1;
    local plain = new_args['plain'] or true;
        
    if source_str == '' or pattern == '' then
        return 0;
    end    
    
    plain = str._getBoolean( plain );

    local start = mw.ustring.find( source_str, pattern, start_pos, plain )
    if start == nil then
        start = 0
    end
    
    return start
end

--[[
replace

This function allows one to replace a target string or pattern within another
string.

用法:
{{#invoke:String|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}}
OR
{{#invoke:String|replace|source=source_string|pattern=pattern_string|replace=replace_string|
   count=replacement_count|plain=plain_flag}}

参数:
    source: The string to search
    pattern: The string or pattern to find within source
    replace: The replacement text
    count: The number of occurences to replace, 默认为 all.
    plain: 指示 pattern 参数是否视为"字符串"而非 Lua 风格的正则表达式的 Boolean 标记, 默认为 true。
]]
function str.replace( frame )
    local new_args = str._getParameters( frame.args, {'source', 'pattern', 'replace', 'count', 'plain' } ); 
    local source_str = new_args['source'] or '';
    local pattern = new_args['pattern'] or '';
    local replace = new_args['replace'] or '';
    local count = tonumber( new_args['count'] );
    local plain = new_args['plain'] or true;
        
    if source_str == '' or pattern == '' then
        return source_str;
    end    
    plain = str._getBoolean( plain );

    if plain then
        pattern = str._escapePattern( pattern );
        replace = mw.ustring.gsub( replace, "%%", "%%%%" ); --Only need to escape replacement sequences.
    end
    
    local result;

    if count ~= nil then
        result = mw.ustring.gsub( source_str, pattern, replace, count );
    else
        result = mw.ustring.gsub( source_str, pattern, replace );
    end        

    return result;
end

--[[ 
    simple function to pipe string.rep to templates.
]]

function str.rep( frame )
    local repetitions = tonumber( frame.args[2] )
    if not repetitions then 
        return str._error( 'function rep expects a number as second parameter, received "' .. ( frame.args[2] or '' ) .. '"' )
    end
    return string.rep( frame.args[1] or '', repetitions )
end


function str.split(inputstr, sep, no_pattern, ignore_null)
	--#invoke 支持
	if type(inputstr) == type({table}) then
		if not getArgs then getArgs = require('Module:Arguments').getArgs end
		args = getArgs(inputstr, {parentFirst=true})
		for arg_name, arg_value in pairs( args ) do
			if arg_name == 1 or arg_name == '1' or arg_name == "str" or arg_name == "inputstr" or arg_name == "input" then
				input_str = arg_value
			elseif arg_name == 2 or arg_name == '2' or arg_name == "sep" or arg_name == "separator" then
				separ = arg_value
			elseif arg_name == 3 or arg_name == '3' or arg_name == "no_pattern" or arg_name == "no pattern" then
				no_pattern_flag = arg_value
			elseif arg_name == 4 or arg_name == '4' or arg_name == "ignore_null" or arg_name == "ignore null" then
				ignore_null_flag = arg_value
			elseif arg_name == 5 or arg_name == '5' or arg_name == "format" then
				format = arg_value or "*{{{1}}}\n";
			end
		end
		if not yesno then yesno = require('Module:Yesno') end
		no_pattern_flag = yesno( no_pattern_flag or 'yes' )
		ignore_null_flag = yesno( ignore_null_flag or 'no' )
		is_invoke = true
		format = mw.ustring.gsub(format or "*{{{1}}}\n", "%{%{%{.-%}%}%}", "%%s" );
		it = mw.ustring.find(format, "%%s", 1)
		if it == nil then format = format .. "%s" end
		format = mw.ustring.gsub(format, "\\n", "\n")
	else
		input_str = inputstr
		separ = sep
		no_pattern_flag = no_pattern
		ignore_null_flag = ignore_null
		is_invoke = false
	end
	input_str = input_str or '' 
	separ = separ or "%s"
	if no_pattern_flag == nil then no_pattern_flag = true end
	if ignore_null_flag == nil then ignore_null_flag = false end

	length = mw.ustring.len(input_str)
	--split函数起点
	if no_pattern_flag then
		separ = mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(separ, 
			"%[", "%["), "%]", "%]"), "%{", "%{"), "%}", "%}"), "%%", "%%%%"), "%)", "%)"), "%-", "%-"),
			"%^", "%^"), "%$", "%$"), "%(", "%("), "%.", "%."), "%*", "%*"), "%+", "%+"), "%|", "%|");
	end
	iterator = 1 ; i = 1 ; flag = true
	result = {}
	separ_str_begin, separ_str_end = mw.ustring.find(input_str, separ, iterator)
	--
	debug1 = 1
	--
	while flag do
		debug1 = debug1 + 1
		if separ_str_begin == nil or iterator > length or debug1 >= 100 then
			separ_str_begin = 0
			separ_str_end = -2
			flag = false
		end
		if separ_str_end < separ_str_begin then separ_str_end = separ_str_begin end
		finded_str = mw.ustring.sub(input_str, iterator, separ_str_begin - 1)
		if not(mw.text.trim(finded_str) == '' and ignore_null_flag) then
			result[i] = finded_str
			i = i + 1
		end

		iterator = separ_str_end + 1
		separ_str_begin, separ_str_end = mw.ustring.find(input_str, separ, iterator)
	end
	if is_invoke then
		body = ''
		for i, result_str in pairs( result ) do
			body = body .. mw.ustring.gsub(format, "%%s", result_str)
		end
		return body
	end
	return result;
end

--[[
join

合并所有非空参数；第一个参数是分隔符。

用法:
{{#invoke:String|join|分隔符|文字1|文字2|文字3}}
]]
function str.join(frame)
	local args = {}
	local sep
	for _, v in ipairs( frame.args ) do
		if sep then
			if v ~= '' then
				table.insert(args, v)
			end
		else
			sep = v
		end
	end
	return table.concat( args, sep or '' )
end

--[[
Helper function that populates the argument list given that user may need to use a mix of
named and unnamed parameters.  This is relevant because named parameters are not
identical to unnamed parameters due to string trimming, and when dealing with strings
we sometimes want to either preserve or remove that whitespace depending on the application.
]]
function str._getParameters( frame_args, arg_list )
    local new_args = {};
    local index = 1;
    local value;
    
    for i,arg in ipairs( arg_list ) do
        value = frame_args[arg]
        if value == nil then
            value = frame_args[index];
            index = index + 1;
        end
        new_args[arg] = value;
    end
    
    return new_args;
end        

--[[
处理报错信息的辅助函数。
]]
function str._error( error_str )
    local frame = mw.getCurrentFrame();
    local error_category = frame.args.error_category or '字符串模块报告的错误';
    local ignore_errors = frame.args.ignore_errors or false;
    local no_category = frame.args.no_category or false;
    
    if str._getBoolean(ignore_errors) then
        return '';
    end
    
    local error_str = '<strong class="error">字符串模块出错：' .. error_str .. '</strong>';
    if error_category ~= '' and not str._getBoolean( no_category ) then
        error_str = '[[Category:' .. error_category .. ']]' .. error_str;
    end        
    
    return error_str;
end

--[[
解析 boolean strings 的辅助函数。
]]
function str._getBoolean( boolean_str )
    local boolean_value;
    
    if type( boolean_str ) == 'string' then
        boolean_str = boolean_str:lower();
        if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0' 
                or boolean_str == '' then
            boolean_value = false;
        else
            boolean_value = true;
        end    
    elseif type( boolean_str ) == 'boolean' then
        boolean_value = boolean_str;
    else
        error( '找不到布尔值' );
    end    
    return boolean_value
end

--[[
转换正则表达式字符，使之能作为普通字符串解析的辅助函数。
]]
function str._escapePattern( pattern_str )
    return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );
end

return str