Difference between revisions of "Module:String"

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what>Mr. Stradivarius
(Add "rep" function per request by User:קיפודנחש at Wikipedia:Lua requests#Template:Loop and Template:Loop15. Copied from sandbox.)
m (48 revisions imported: Information box for pictures template)
 
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Line 1: Line 1:
--[[
+
--[[
  
 
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.
 
]]
 
]]
Line 39: Line 39:
  
 
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
  
Line 61: Line 61:
 
     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 );
 
  
    -- Convert negatives for range checking
+
local len = mw.ustring.len( s );
    if i < 0 then
+
 
        i = len + i + 1;
+
-- Convert negatives for range checking
    end
+
if i < 0 then
    if j < 0 then
+
i = len + i + 1;
        j = len + j + 1;
+
end
    end
+
if j < 0 then
   
+
j = len + j + 1;
    if i > len or j > len or i < 1 or j < 1 then
+
end
        return str._error( 'String subset index out of range' );
+
 
    end
+
if i > len or j > len or i < 1 or j < 1 then
    if j < i then
+
return str._error( 'String subset index out of range' );
        return str._error( 'String subset indices out of order' );
+
end
    end
+
if j < i then
   
+
return str._error( 'String subset indices out of order' );
    return mw.ustring.sub( s, i, j )
+
end
 +
 
 +
return mw.ustring.sub( s, i, j )
 
end
 
end
  
Line 101: Line 101:
 
]]
 
]]
 
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
  
Line 109: Line 109:
 
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.
  
Line 123: Line 123:
 
     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.
Line 133: Line 133:
  
 
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:
  
* http://www.lua.org/manual/5.1/manual.html#5.4.1
+
* https://www.lua.org/manual/5.1/manual.html#5.4.1
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
+
* https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Ustring_patterns
+
* https://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'];
   
+
 
    if s == '' then
+
return str._match( s, pattern, start, match_index, plain, nomatch )
        return str._error( 'Target string is empty' );
 
    end
 
    if pattern == '' then
 
        return str._error( 'Pattern string is empty' );
 
    end
 
    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
 
end
  
Line 231: Line 237:
  
 
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.
  
Line 242: Line 248:
 
]]
 
]]
 
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
+
if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then
        return str._error( 'String index out of range' );
+
return str._error( 'String index out of range' );
    end  
+
end
   
+
 
    return mw.ustring.sub( target_str, pos, pos );
+
return mw.ustring.sub( target_str, pos, pos );
 
end
 
end
  
Line 257: Line 263:
  
 
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.
  
Line 268: Line 274:
 
]]
 
]]
 
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
  
    if target_str == '' then
+
return start
        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
  
Line 303: Line 309:
  
 
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.
Line 314: Line 320:
 
]]
 
]]
 
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
 
        return 0;
 
    end   
 
   
 
    plain = str._getBoolean( plain );
 
  
    local start = mw.ustring.find( source_str, pattern, start_pos, plain )
+
if source_str == '' or pattern == '' then
    if start == nil then
+
return 0;
        start = 0
+
end
    end
+
 
   
+
plain = str._getBoolean( plain );
    return start
+
 
 +
local start = mw.ustring.find( source_str, pattern, start_pos, plain )
 +
if start == nil then
 +
start = 0
 +
end
 +
 
 +
return start
 
end
 
end
  
Line 352: Line 358:
 
     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 plain then
+
if source_str == '' or pattern == '' then
        pattern = str._escapePattern( pattern );
+
return source_str;
        replace = mw.ustring.gsub( replace, "%%", "%%%%" ); --Only need to escape replacement sequences.
+
end
    end
+
plain = str._getBoolean( plain );
   
 
    local result;
 
  
    if count ~= nil then
+
if plain then
        result = mw.ustring.gsub( source_str, pattern, replace, count );
+
pattern = str._escapePattern( pattern );
    else
+
replace = mw.ustring.gsub( replace, "%%", "%%%%" ); --Only need to escape replacement sequences.
        result = mw.ustring.gsub( source_str, pattern, replace );
+
end
    end      
 
  
    return result;
+
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
 
end
  
--[[  
+
--[[
 
     simple function to pipe string.rep to templates.
 
     simple function to pipe string.rep to templates.
 
]]
 
]]
  
 
function str.rep( frame )
 
function str.rep( frame )
    local repetitions = tonumber( frame.args[2] )
+
local repetitions = tonumber( frame.args[2] )
    if not repetitions then  
+
if not repetitions then
        return str._error( 'function rep expects a number as second parameter, received "' .. ( frame.args[2] or '' ) .. '"' )
+
return str._error( 'function rep expects a number as second parameter, received "' .. ( frame.args[2] or '' ) .. '"' )
    end
+
end
    return string.rep( frame.args[1] or '', repetitions )
+
return string.rep( frame.args[1] or '', repetitions )
 +
end
 +
 
 +
--[[
 +
escapePattern
 +
 
 +
This function escapes special characters from a Lua string pattern. See [1]
 +
for details on how patterns work.
 +
 
 +
[1] https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
 +
 
 +
Usage:
 +
{{#invoke:String|escapePattern|pattern_string}}
 +
 
 +
Parameters
 +
    pattern_string: The pattern string to escape.
 +
]]
 +
function str.escapePattern( frame )
 +
local pattern_str = frame.args[1]
 +
if not pattern_str then
 +
return str._error( 'No pattern string specified' );
 +
end
 +
local result = str._escapePattern( pattern_str )
 +
return result
 
end
 
end
  
Line 402: Line 431:
 
]]
 
]]
 
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
  
 
--[[
 
--[[
Line 422: Line 451:
 
]]
 
]]
 
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 'Errors reported by Module 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">String Module Error: ' .. 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 = '[[Category:' .. error_category .. ']]' .. error_str;
    end      
+
end
   
+
 
    return error_str;
+
return error_str;
 
end
 
end
  
Line 443: Line 472:
 
]]
 
]]
 
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( 'No boolean value found' );
    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

Latest revision as of 13:30, 8 October 2019

--[[

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 = {}

--[[ len

This function returns the length of the target string.

Usage: Script error: No such module "String". OR Script error: No such module "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: Script error: No such module "String". OR Script error: No such module "String".

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( '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 ) end

--[[ This function implements that features of Template: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: Script error: No such module "String". OR Script error: No such module "String".

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:

]] -- 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 ) 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'];

return str._match( s, pattern, start, match_index, plain, nomatch ) end

--[[ pos

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

Usage: Script error: No such module "String". OR Script error: No such module "String".

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( 'String index out of range' ); end

return mw.ustring.sub( target_str, pos, pos ); end

--[[ str_find

This function duplicates the behavior of Template: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: Script error: No such module "String". OR Script error: No such module "String".

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: Script error: No such module "String". OR Script error: No such module "String".

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

--[[

   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

--[[ escapePattern

This function escapes special characters from a Lua string pattern. See [1] for details on how patterns work.

[1] https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns

Usage: Script error: No such module "String".

Parameters

   pattern_string: The pattern string to escape.

]] function str.escapePattern( frame ) local pattern_str = frame.args[1] if not pattern_str then return str._error( 'No pattern string specified' ); end local result = str._escapePattern( pattern_str ) return result 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 'Errors reported by Module 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 = 'String Module Error: ' .. error_str .. ''; if error_category ~= and not str._getBoolean( no_category ) then error_str = .. 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( 'No boolean value found' ); 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