Модуль:String: различия между версиями

Материал из FetbukWiki
https://www.mediawiki.org/wiki/>Amire80
(remove seemingly unnecessary letter)
 
м (1 версия импортирована)
 
(не показаны 4 промежуточные версии 3 участников)
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--[[
--[[


This module is intended to provide access to basic string functions.
This module is intended to provide access to basic string functions.


Most of the functions provided here can be invoked with named parameters,
Most of the functions provided here can be invoked with named parameters,  
unnamed parameters, or a mixture.  If named parameters are used, Mediawiki will
unnamed parameters, or a mixture.  If named parameters are used, Mediawiki will  
automatically remove any leading or trailing whitespace from the parameter.
automatically remove any leading or trailing whitespace from the parameter.
Depending on the intended use, it may be advantageous to either preserve or
Depending on the intended use, it may be advantageous to either preserve or
remove such whitespace.
remove such whitespace.


Global options
Global options
     ignore_errors: If set to 'true' or 1, any error condition will result in
     ignore_errors: If set to 'true' or 1, any error condition will result in  
         an empty string being returned rather than an error message.
         an empty string being returned rather than an error message.
 
       
     error_category: If an error occurs, specifies the name of a category to
     error_category: If an error occurs, specifies the name of a category to  
         include with the error message.  The default category is
         include with the error message.  The default category is
         [Category:Errors reported by Module String].
         [Category:Errors reported by Module String].
 
       
     no_category: If set to 'true' or 1, no category will be added if an error
     no_category: If set to 'true' or 1, no category will be added if an error
         is generated.
         is generated.
 
       
Unit tests for this module are available at Module:String/tests.
Unit tests for this module are available at Module:String/tests.
]]
]]


local str = {}
local str = {}
--[[
subcount
This function returns the count of substring in source string.
Usage:
{{#invoke:String|subcount|source_string|substring|plain_flag}}
OR
{{#invoke:String|subcount|s=source_string|pattern=substring|plain=plain_flag}}
Parameters
    s: The string to search
    pattern: The pattern or string to find within the string
    plain: A flag indicating that the substring should be understood as plain
        text. Defaults to true.
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string. 
]]
function str.subcount( frame )
    local new_args = str._getParameters( frame.args, {'s', 'pattern', 'plain'} );
    local s = new_args['s'] or '';
    local plain_flag = str._getBoolean( new_args['plain'] or true );
    local pattern = new_args['pattern'] or '';
    if s == '' or pattern == '' then
    return 0;
    end
   
    if plain_flag then
        pattern = str._escapePattern( pattern );
    end
   
    local _, count = mw.ustring.gsub(s, pattern, "")
    return count;
end


--[[
--[[
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If invoked using named parameters, Mediawiki will automatically remove any leading or
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string.
trailing whitespace from the target string.
]]
]]
function str.len( frame )
function str.len( frame )
local new_args = str._getParameters( frame.args, {'s'} );
    local new_args = str._getParameters( frame.args, {'s'} );
local s = new_args['s'] or '';
    local s = new_args['s'] or '';
return mw.ustring.len( s )
    return mw.ustring.len( s )
end
end


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     i: The fist index of the substring to return, defaults to 1.
     i: The fist index of the substring to return, defaults to 1.
     j: The last index of the string to return, defaults to the last character.
     j: The last index of the string to return, defaults to the last character.
 
   
The first character of the string is assigned an index of 1.  If either i or j
The first character of the string is assigned an index of 1.  If either i or j
is a negative value, it is interpreted the same as selecting a character by
is a negative value, it is interpreted the same as selecting a character by  
counting from the end of the string.  Hence, a value of -1 is the same as
counting from the end of the string.  Hence, a value of -1 is the same as  
selecting the last character of the string.
selecting the last character of the string.


If the requested indices are out of range for the given string, an error is
If the requested indices are out of range for the given string, an error is  
reported.
reported.
]]
]]
function str.sub( frame )
function str.sub( frame )
local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } );
    local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } );
local s = new_args['s'] or '';
    local s = new_args['s'] or '';
local i = tonumber( new_args['i'] ) or 1;
    local i = tonumber( new_args['i'] ) or 1;
local j = tonumber( new_args['j'] ) or -1;
    local j = tonumber( new_args['j'] ) or -1;
 
   
local len = mw.ustring.len( s );
    local len = mw.ustring.len( s );
 
-- Convert negatives for range checking
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( 'String subset index out of range' );
end
if j < i then
return str._error( 'String subset indices out of order' );
end


return mw.ustring.sub( s, i, j )
    -- Convert negatives for range checking
    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( 'Значение индекса подстроки выходит за допустимые границы' );
    end
    if j < i then
        return str._error( 'Неверный порядок индексов подстроки' );
    end
   
    return mw.ustring.sub( s, i, j )
end
end


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]]
]]
function str.sublength( frame )
function str.sublength( frame )
local i = tonumber( frame.args.i ) or 0
    local i = tonumber( frame.args.i ) or 0
local len = tonumber( frame.args.len )
    local len = tonumber( frame.args.len )
return mw.ustring.sub( frame.args.s, i + 1, len and ( i + len ) )
    return mw.ustring.sub( frame.args.s, i + 1, len and ( i + len ) )
end
end


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match
match


This function returns a substring from the source string that matches a
This function returns a substring from the source string that matches a  
specified pattern.
specified pattern.


Usage:
Usage:
{{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch}}
{{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch_output}}
OR
OR
{{#invoke:String|pos|s=source_string|pattern=pattern_string|start=start_index
{{#invoke:String|pos|s=source_string|pattern=pattern_string|start=start_index
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     start: The index within the source string to start the search.  The first
     start: The index within the source string to start the search.  The first
         character of the string has index 1.  Defaults to 1.
         character of the string has index 1.  Defaults to 1.
     match: In some cases it may be possible to make multiple matches on a single
     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
         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
         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
         counting from the last match.  Hence match = -1 is the same as requesting
         the last match.  Defaults to 1.
         the last match.  Defaults to 1.
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If invoked using named parameters, Mediawiki will automatically remove any leading or
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from each string.  In some circumstances this is desirable, in
trailing whitespace from each string.  In some circumstances this is desirable, in  
other cases one may want to preserve the whitespace.
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
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.
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
If one adds the parameter ignore_errors=true, then the error will be suppressed and  
an empty string will be returned on any failure.
an empty string will be returned on any failure.


For information on constructing Lua patterns, a form of [regular expression], see:
For information on constructing Lua patterns, a form of [regular expression], see:


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


]]
]]
-- This sub-routine is exported for use in other modules
function str._match( s, pattern, start, match_index, plain, nomatch )
if s == '' then
return str._error( 'Target string is empty' );
end
if pattern == '' then
return str._error( 'Pattern string is empty' );
end
start = tonumber(start) or 1
if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
return str._error( 'Requested start is out of range' );
end
if match_index == 0 then
return str._error( 'Match index is out of range' );
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( 'Match not found' );
else
return nomatch;
end
else
return result;
end
end
-- This is the entry point for #invoke:String|match
function str.match( frame )
function str.match( frame )
local new_args = str._getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain', 'nomatch'} );
    local new_args = str._getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain', 'nomatch'} );
local s = new_args['s'] or '';
    local s = new_args['s'] or '';
local start = tonumber( new_args['start'] ) or 1;
    local start = tonumber( new_args['start'] ) or 1;
local plain_flag = str._getBoolean( new_args['plain'] or false );
    local plain_flag = str._getBoolean( new_args['plain'] or false );
local pattern = new_args['pattern'] or '';
    local pattern = new_args['pattern'] or '';
local match_index = math.floor( tonumber(new_args['match']) or 1 );
    local match_index = math.floor( tonumber(new_args['match']) or 1 );
local nomatch = new_args['nomatch'];
    local nomatch = new_args['nomatch'];
 
   
return str._match( s, pattern, start, match_index, plain, nomatch )
    if s == '' then
        return str._error( 'Пустая строка поиска' );
    end
    if pattern == '' then
        return str._error( 'Пустой шаблон поиска' );
    end
    if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
        return str._error( 'Индекс начала поиска выходит за допустимые границы' );
    end
    if match_index == 0 then
        return str._error( 'Индекс совпадения выходит за допустимые границы' );
    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( 'Совпадение не найдено' );
        else
            return nomatch;
        end
    else
        return result;
    end
end
end


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


The first character has an index value of 1.
The first character has an index value of 1.


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


Строка 248: Строка 278:
]]
]]
function str.pos( frame )
function str.pos( frame )
local new_args = str._getParameters( frame.args, {'target', 'pos'} );
    local new_args = str._getParameters( frame.args, {'target', 'pos'} );
local target_str = new_args['target'] or '';
    local target_str = new_args['target'] or '';
local pos = tonumber( new_args['pos'] ) or 0;
    local pos = tonumber( new_args['pos'] ) or 0;
 
if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then
return str._error( 'String index out of range' );
end


return mw.ustring.sub( target_str, pos, pos );
    if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then
        return str._error( 'Значение индекса строки выходит за допустимые границы' );
    end   
   
    return mw.ustring.sub( target_str, pos, pos );
end
end


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This function duplicates the behavior of {{str_find}}, including all of its quirks.
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
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.
new code and templates.  New code is recommended to use the "find" function instead.


Строка 274: Строка 304:
]]
]]
function str.str_find( frame )
function str.str_find( frame )
local new_args = str._getParameters( frame.args, {'source', 'target'} );
    local new_args = str._getParameters( frame.args, {'source', 'target'} );
local source_str = new_args['source'] or '';
    local source_str = new_args['source'] or '';
local target_str = new_args['target'] 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
    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
end


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


This function returns the first index >= "start" where "target" can be found
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
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 returns 0.  If either "source" or "target" are missing / empty, this
function also returns 0.
function also returns 0.
Строка 320: Строка 350:
]]
]]
function str.find( frame )
function str.find( frame )
local new_args = str._getParameters( frame.args, {'source', 'target', 'start', 'plain' } );
    local new_args = str._getParameters( frame.args, {'source', 'target', 'start', 'plain' } );  
local source_str = new_args['source'] or '';
    local source_str = new_args['source'] or '';
local pattern = new_args['target'] or '';
    local pattern = new_args['target'] or '';
local start_pos = tonumber(new_args['start']) or 1;
    local start_pos = tonumber(new_args['start']) or 1;
local plain = new_args['plain'] or true;
    local plain = new_args['plain'] or true;
 
       
if source_str == '' or pattern == '' then
    if source_str == '' or pattern == '' then
return 0;
        return 0;
end
    end  
 
   
plain = str._getBoolean( plain );
    plain = str._getBoolean( plain );
 
local start = mw.ustring.find( source_str, pattern, start_pos, plain )
if start == nil then
start = 0
end


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


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     count: The number of occurences to replace, defaults to all.
     count: The number of occurences to replace, defaults to all.
     plain: Boolean flag indicating that pattern should be understood as plain
     plain: Boolean flag indicating that pattern should be understood as plain
         text and not as a Lua style regular expression, defaults to true
         text and not as a Lua style regular expression, defaults to true  
]]
]]
function str.replace( frame )
function str.replace( frame )
local new_args = str._getParameters( frame.args, {'source', 'pattern', 'replace', 'count', 'plain' } );
    local new_args = str._getParameters( frame.args, {'source', 'pattern', 'replace', 'count', 'plain' } );  
local source_str = new_args['source'] or '';
    local source_str = new_args['source'] or '';
local pattern = new_args['pattern'] or '';
    local pattern = new_args['pattern'] or '';
local replace = new_args['replace'] or '';
    local replace = new_args['replace'] or '';
local count = tonumber( new_args['count'] );
    local count = tonumber( new_args['count'] );
local plain = new_args['plain'] or true;
    local plain = new_args['plain'] or true;
       
    if source_str == '' or pattern == '' then
        return source_str;
    end   
    plain = str._getBoolean( plain );


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


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


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


--[[
This function adds support for escaping parts of the patterns when using [plain=false].
]]
function str.escape( frame )
local new_args = str._getParameters( frame.args, {'pattern' } );
local pattern = new_args['pattern'] or '';
local result = '';
result = str._escapePattern( pattern );
return result;
return result;
end
end


--[[
--[[
    simple function to pipe string.rep to templates.
  Internal compare string function
]]
]]
 
function str._strcmp(a , b)
function str.rep( frame )
    local s1c = mw.ustring.gcodepoint( a );
local repetitions = tonumber( frame.args[2] )
    local s2c = mw.ustring.gcodepoint( b );
if not repetitions then
    while true do
return str._error( 'function rep expects a number as second parameter, received "' .. ( frame.args[2] or '' ) .. '"' )
        local c1 = s1c();
end
        local c2 = s2c();
return string.rep( frame.args[1] or '', repetitions )
        if c1 == nil then
            if c2 == nil then
                return 0
            else
                return -1
            end
        else
            if c2 ~= nil then
                if c1 ~= c2 then
                  return c1 < c2 and -1 or 1
              end
            else
                return 1
            end
        end
    end
    return 0
end
end
 
--[[
--[[
escapePattern
compare


This function escapes special characters from a Lua string pattern. See [1]
This function compare two UTF-8 strings
for details on how patterns work.


[1] https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
Usage:
{{#invoke:String|compare|str1|str2}}


Usage:
Returns:
{{#invoke:String|escapePattern|pattern_string}}
0 - if strings are equal
1 - if st1 > str2
-1 - if str1 < str2
]]
function str.compare(frame)
    local str1 = frame.args[1] or '';
    local str2 = frame.args[2] or '';
    return str._strcmp(str1 , str2)
end


Parameters
--[[
     pattern_string: The pattern string to escape.
     simple function to pipe string.rep to templates.
]]
]]
function str.escapePattern( frame )
local pattern_str = frame.args[1]
function str.rep( frame )
if not pattern_str then
    local repetitions = tonumber( frame.args[2] )
return str._error( 'No pattern string specified' );
    if not repetitions then  
end
        return str._error( 'функция rep ожидает число  во втором параметре, а получено "' .. ( frame.args[2] or '' ) .. '"' )
local result = str._escapePattern( pattern_str )
    end
return result
    return string.rep( frame.args[1] or '', repetitions )
end
end


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]]
]]
function str._getParameters( frame_args, arg_list )
function str._getParameters( frame_args, arg_list )
local new_args = {};
    local new_args = {};
local index = 1;
    local index = 1;
local value;
    local value;
 
   
for i,arg in ipairs( arg_list ) do
    for i,arg in ipairs( arg_list ) do
value = frame_args[arg]
        value = frame_args[arg]
if value == nil then
        if value == nil then
value = frame_args[index];
            value = frame_args[index];
index = index + 1;
            index = index + 1;
end
        end
new_args[arg] = value;
        new_args[arg] = value;
end
    end
 
   
return new_args;
    return new_args;
end
end      


--[[
--[[
Строка 451: Строка 517:
]]
]]
function str._error( error_str )
function str._error( error_str )
local frame = mw.getCurrentFrame();
    local frame = mw.getCurrentFrame();
local error_category = frame.args.error_category or 'Errors reported by Module String';
    local error_category = frame.args.error_category or 'Страницы с ошибками модуля String';
local ignore_errors = frame.args.ignore_errors or false;
    local ignore_errors = frame.args.ignore_errors or false;
local no_category = frame.args.no_category or false;
    local no_category = frame.args.no_category or false;
 
   
if str._getBoolean(ignore_errors) then
    if str._getBoolean(ignore_errors) then
return '';
        return '';
end
    end
 
   
local error_str = '<strong class="error">String Module Error: ' .. error_str .. '</strong>';
    local error_str = '<strong class="error">Ошибка модуля String: ' .. error_str .. '</strong>';
if error_category ~= '' and not str._getBoolean( no_category ) then
    if error_category ~= '' and not str._getBoolean( no_category ) then
error_str = '[[Category:' .. error_category .. ']]' .. error_str;
        error_str = '[[Категория:' .. error_category .. ']]' .. error_str;
end
    end      
 
   
return error_str;
    return error_str;
end
end


Строка 472: Строка 538:
]]
]]
function str._getBoolean( boolean_str )
function str._getBoolean( boolean_str )
local boolean_value;
    local boolean_value;
 
   
if type( boolean_str ) == 'string' then
    if type( boolean_str ) == 'string' then
boolean_str = boolean_str:lower();
        boolean_str = boolean_str:lower();
if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0'
        if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0'  
or boolean_str == '' then
                or boolean_str == '' then
boolean_value = false;
            boolean_value = false;
else
        else
boolean_value = true;
            boolean_value = true;
end
        end  
elseif type( boolean_str ) == 'boolean' then
    elseif type( boolean_str ) == 'boolean' then
boolean_value = boolean_str;
        boolean_value = boolean_str;
else
    else
error( 'No boolean value found' );
        error( 'Логическое значение не найдено' );
end
    end  
return boolean_value
    return boolean_value
end
end


--[[
--[[
Helper function that escapes all pattern characters so that they will be treated
Helper function that escapes all pattern characters so that they will be treated  
as plain text.
as plain text.
]]
]]
function str._escapePattern( pattern_str )
function str._escapePattern( pattern_str )
return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );
    return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );
end
end


return str
return str

Текущая версия от 01:00, 12 марта 2022

Для документации этого модуля может быть создана страница Модуль:String/doc

--[[  

This module is intended to provide access to basic string functions.

Most of the functions provided here can be invoked with named parameters, 
unnamed parameters, or a mixture.  If named parameters are used, Mediawiki will 
automatically remove any leading or trailing whitespace from the parameter.  
Depending on the intended use, it may be advantageous to either preserve or
remove such whitespace.

Global options
    ignore_errors: If set to 'true' or 1, any error condition will result in 
        an empty string being returned rather than an error message.  
        
    error_category: If an error occurs, specifies the name of a category to 
        include with the error message.  The default category is  
        [Category:Errors reported by Module String].
        
    no_category: If set to 'true' or 1, no category will be added if an error
        is generated.
        
Unit tests for this module are available at Module:String/tests.
]]

local str = {}

--[[
subcount

This function returns the count of substring in source string.

Usage:
{{#invoke:String|subcount|source_string|substring|plain_flag}}
OR
{{#invoke:String|subcount|s=source_string|pattern=substring|plain=plain_flag}}

Parameters
    s: The string to search
    pattern: The pattern or string to find within the string
    plain: A flag indicating that the substring should be understood as plain
        text. Defaults to true.

If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string.  
]]
function str.subcount( frame )
    local new_args = str._getParameters( frame.args, {'s', 'pattern', 'plain'} );
    local s = new_args['s'] or '';
    local plain_flag = str._getBoolean( new_args['plain'] or true );
    local pattern = new_args['pattern'] or '';
    if s == '' or pattern == '' then
    	return 0;
    end
    	
    if plain_flag then
        pattern = str._escapePattern( pattern );
    end
    
    local _, count = mw.ustring.gsub(s, pattern, "")
    return count;
end

--[[
len

This function returns the length of the target string.

Usage:
{{#invoke:String|len|target_string|}}
OR
{{#invoke:String|len|s=target_string}}

Parameters
    s: The string whose length to report

If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string.  
]]
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

This function returns a substring of the target string at specified indices.

Usage:
{{#invoke:String|sub|target_string|start_index|end_index}}
OR
{{#invoke:String|sub|s=target_string|i=start_index|j=end_index}}

Parameters
    s: The string to return a subset of
    i: The fist index of the substring to return, defaults to 1.
    j: The last index of the string to return, defaults to the last character.
    
The first character of the string is assigned an index of 1.  If either i or j
is a negative value, it is interpreted the same as selecting a character by 
counting from the end of the string.  Hence, a value of -1 is the same as 
selecting the last character of the string.

If the requested indices are out of range for the given string, an error is 
reported.
]]
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 );

    -- Convert negatives for range checking
    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( 'Значение индекса подстроки выходит за допустимые границы' );
    end
    if j < i then
        return str._error( 'Неверный порядок индексов подстроки' );
    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

This function returns a substring from the source string that matches a 
specified pattern.

Usage:
{{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch_output}}
OR
{{#invoke:String|pos|s=source_string|pattern=pattern_string|start=start_index
    |match=match_number|plain=plain_flag|nomatch=nomatch_output}}

Parameters
    s: The string to search
    pattern: The pattern or string to find within the string
    start: The index within the source string to start the search.  The first
        character of the string has index 1.  Defaults to 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.  Defaults to 1.
    plain: A flag indicating that the pattern should be understood as plain
        text.  Defaults to false.
    nomatch: If no match is found, output the "nomatch" value rather than an error.

If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from each string.  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.

For information on constructing Lua patterns, a form of [regular expression], see:

* 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( 'Пустая строка поиска' );
    end
    if pattern == '' then
        return str._error( 'Пустой шаблон поиска' );
    end
    if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
        return str._error( 'Индекс начала поиска выходит за допустимые границы' );
    end
    if match_index == 0 then
        return str._error( 'Индекс совпадения выходит за допустимые границы' );
    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( 'Совпадение не найдено' );
        else
            return nomatch;
        end
    else
        return result;
    end
end

--[[
pos

This function returns a single character from the target string at position pos.

Usage:
{{#invoke:String|pos|target_string|index_value}}
OR
{{#invoke:String|pos|target=target_string|pos=index_value}}

Parameters
    target: The string to search
    pos: The index for the character to return

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.

The first character has an index value of 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( 'Значение индекса строки выходит за допустимые границы' );
    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.

Usage:
{{#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}}

Parameters
    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, defaults to 1
    plain: Boolean flag indicating that target should be understood as plain
        text and not as a Lua style regular expression, defaults to 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.

Usage:
{{#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}}

Parameters
    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, defaults to all.
    plain: Boolean flag indicating that pattern should be understood as plain
        text and not as a Lua style regular expression, defaults to 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

--[[
This function adds support for escaping parts of the patterns when using [plain=false].
]]
function str.escape( frame )
	local new_args = str._getParameters( frame.args, {'pattern' } );
	local pattern = new_args['pattern'] or '';
	
	local result = '';
	result = str._escapePattern( pattern );
	return result;
end

--[[
  Internal compare string function
]]
function str._strcmp(a , b)
    local s1c = mw.ustring.gcodepoint( a );
    local s2c = mw.ustring.gcodepoint( b );
    while true do
        local c1 = s1c();
        local c2 = s2c();
        if c1 == nil then
            if c2 == nil then
                return 0
            else
                return -1
            end
        else
            if c2 ~= nil then
                if c1 ~= c2 then
                  return c1 < c2 and -1 or 1
              end
            else
                return 1
            end
        end
    end
    return 0
end
 
--[[
compare

This function compare two UTF-8 strings

Usage:
{{#invoke:String|compare|str1|str2}}

Returns:
 0 - if strings are equal
 1 - if st1 > str2
-1 - if str1 < str2
]]
function str.compare(frame)
    local str1 = frame.args[1] or '';
    local str2 = frame.args[2] or '';
    return str._strcmp(str1 , str2)
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( 'функция rep ожидает число  во втором параметре, а получено "' .. ( frame.args[2] or '' ) .. '"' )
    end
    return string.rep( frame.args[1] or '', repetitions )
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        

--[[
Helper function to handle error messages.
]]
function str._error( error_str )
    local frame = mw.getCurrentFrame();
    local error_category = frame.args.error_category or 'Страницы с ошибками модуля String';
    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">Ошибка модуля String: ' .. error_str .. '</strong>';
    if error_category ~= '' and not str._getBoolean( no_category ) then
        error_str = '[[Категория:' .. error_category .. ']]' .. error_str;
    end        
    
    return error_str;
end

--[[
Helper Function to interpret boolean strings
]]
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( 'Логическое значение не найдено' );
    end    
    return boolean_value
end

--[[
Helper function that escapes all pattern characters so that they will be treated 
as plain text.
]]
function str._escapePattern( pattern_str )
    return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );
end

return str