Difference between revisions of "Module:String"

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local str = {}
+
--[[
 +
 
 +
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.
  
-- Cannot include null byte.
+
Global options
local UTF8_char = "[\1-\127\194-\244][\128-\191]*"
+
    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
ulen
+
        include with the error message.  The default category is
 +
        [Category:Errors reported by Module String].
  
Counts UTF-8 characters. Faster than mw.ustring.len.
+
    no_category: If set to 'true' or 1, no category will be added if an error
 +
        is generated.
  
Assumes that the encoding is correct. Unlike mw.ustring.len, does not return nil
+
Unit tests for this module are available at Module:String/tests.
if encoding is invalid.
+
]]
  
Does not count the bytes 192, 193, and 245-255. They are not used in UTF-8 and
+
local str = {}
will not occur if the string is valid. They are replaced with the replacement
 
character (U+FFFD) on MediaWiki pages.
 
--]]
 
function str.ulen(text)
 
local _, length = string.gsub(text, UTF8_char, "")
 
return length
 
end
 
  
 
--[[
 
--[[
Line 27: Line 31:
  
 
Usage:
 
Usage:
{{#invoke:string|len|target_string|}}
+
{{#invoke:String|len|target_string|}}
 
OR
 
OR
{{#invoke:string|len|s=target_string}}
+
{{#invoke:String|len|s=target_string}}
  
 
Parameters
 
Parameters
Line 37: Line 41:
 
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 49: Line 53:
  
 
Usage:
 
Usage:
{{#invoke:string|sub|target_string|start_index|end_index}}
+
{{#invoke:String|sub|target_string|start_index|end_index}}
 
OR
 
OR
{{#invoke:string|sub|s=target_string|i=start_index|j=end_index}}
+
{{#invoke:String|sub|s=target_string|i=start_index|j=end_index}}
  
 
Parameters
 
Parameters
Line 57: 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
Line 66: Line 70:
 
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
 
-- Convert negatives for range checking
 
if i < 0 then
 
if i < 0 then
Line 81: Line 85:
 
j = len + j + 1;
 
j = len + j + 1;
 
end
 
end
+
 
 
if i > len or j > len or i < 1 or j < 1 then
 
if i > len or j > len or i < 1 or j < 1 then
return str._error('String subset index out of range');
+
return str._error( 'String subset index out of range' );
 
end
 
end
 
if j < i then
 
if j < i then
return str._error('String subset indices out of order');
+
return str._error( 'String subset indices out of order' );
 
end
 
end
+
 
return mw.ustring.sub(s, i, j)
+
return mw.ustring.sub( s, i, j )
 
end
 
end
  
Line 96: Line 100:
 
to maintain these older templates.
 
to maintain these older templates.
 
]]
 
]]
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 113:
  
 
Usage:
 
Usage:
{{#invoke:string|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch_output}}
+
{{#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
 
     |match=match_number|plain=plain_flag|nomatch=nomatch_output}}
 
     |match=match_number|plain=plain_flag|nomatch=nomatch_output}}
  
Line 144: Line 148:
  
 
]]
 
]]
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
 
if s == '' then
return str._error('Target string is empty');
+
return str._error( 'Target string is empty' );
 
end
 
end
 
if pattern == '' then
 
if pattern == '' then
return str._error('Pattern string is empty');
+
return str._error( 'Pattern string is empty' );
 
end
 
end
if math.abs(start) < 1 or math.abs(start) > mw.ustring.len(s) then
+
if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
return str._error('Requested start is out of range');
+
return str._error( 'Requested start is out of range' );
 
end
 
end
 
if match_index == 0 then
 
if match_index == 0 then
return str._error('Match index is out of range');
+
return str._error( 'Match index is out of range' );
 
end
 
end
 
if plain_flag then
 
if plain_flag then
pattern = str.pattern_escape(pattern);
+
pattern = str._escapePattern( pattern );
 
end
 
end
+
 
 
local result
 
local result
 
if match_index == 1 then
 
if match_index == 1 then
 
-- Find first match is simple case
 
-- Find first match is simple case
result = mw.ustring.match(s, pattern, start)
+
result = mw.ustring.match( s, pattern, start )
 
else
 
else
 
if start > 1 then
 
if start > 1 then
s = mw.ustring.sub(s, start);
+
s = mw.ustring.sub( s, start );
 
end
 
end
+
 
 
local iterator = mw.ustring.gmatch(s, pattern);
 
local iterator = mw.ustring.gmatch(s, pattern);
 
if match_index > 0 then
 
if match_index > 0 then
Line 196: Line 200:
 
count = count + 1;
 
count = count + 1;
 
end
 
end
+
 
result = result_table[count + match_index];
+
result = result_table[ count + match_index ];
 
end
 
end
 
end
 
end
+
 
 
if result == nil then
 
if result == nil then
 
if nomatch == nil then
 
if nomatch == nil then
return str._error('Match not found');
+
return str._error( 'Match not found' );
 
else
 
else
 
return nomatch;
 
return nomatch;
Line 218: Line 222:
  
 
Usage:
 
Usage:
{{#invoke:string|pos|target_string|index_value}}
+
{{#invoke:String|pos|target_string|index_value}}
 
OR
 
OR
{{#invoke:string|pos|target=target_string|pos=index_value}}
+
{{#invoke:String|pos|target=target_string|pos=index_value}}
  
 
Parameters
 
Parameters
Line 237: Line 241:
 
A requested value of zero, or a value greater than the length of the string returns an error.
 
A requested value of zero, or a value greater than the length of the string returns an error.
 
]]
 
]]
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 263: Line 267:
 
separatetly.
 
separatetly.
 
]]
 
]]
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
 
if target_str == '' then
 
return 1;
 
return 1;
 
end
 
end
+
 
local start = mw.ustring.find(source_str, target_str, 1, true)
+
local start = mw.ustring.find( source_str, target_str, 1, true )
 
if start == nil then
 
if start == nil then
 
start = -1
 
start = -1
 
end
 
end
+
 
 
return start
 
return start
 
end
 
end
Line 287: Line 291:
  
 
Usage:
 
Usage:
{{#invoke:string|find|source_str|target_string|start_index|plain_flag}}
+
{{#invoke:String|find|source_str|target_string|start_index|plain_flag}}
 
OR
 
OR
{{#invoke:string|find|source=source_str|target=target_str|start=start_index|plain=plain_flag}}
+
{{#invoke:String|find|source=source_str|target=target_str|start=start_index|plain=plain_flag}}
  
 
Parameters
 
Parameters
Line 304: Line 308:
 
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 an empty string.  If either "source" or "target" are missing / empty, this
+
function returns 0.  If either "source" or "target" are missing / empty, this
function also returns an empty string.
+
function also returns 0.
  
 
This function should be safe for UTF-8 strings.
 
This function should be safe for UTF-8 strings.
 
]]
 
]]
function str.find(frame)
+
function str.find( frame )
local params = {
+
local new_args = str._getParameters( frame.args, {'source', 'target', 'start', 'plain' } );
[1] = { required = true },
+
local source_str = new_args['source'] or '';
[2] = { required = true },
+
local pattern = new_args['target'] or '';
[3] = { type = "number" },
+
local start_pos = tonumber(new_args['start']) or 1;
[4] = { type = "boolean" },
+
local plain = new_args['plain'] or true;
}
+
 
+
if source_str == '' or pattern == '' then
local args = require("Module:parameters").process(frame.args, params)
+
return 0;
+
end
return mw.ustring.find(args[1], args[2], args[3], args[4])
+
 
 +
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
 
end
  
Line 329: Line 341:
  
 
Usage:
 
Usage:
{{#invoke:string|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}}
+
{{#invoke:String|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}}
 
OR
 
OR
{{#invoke:string|replace|source=source_string|pattern=pattern_string|replace=replace_string|
+
{{#invoke:String|replace|source=source_string|pattern=pattern_string|replace=replace_string|
 
   count=replacement_count|plain=plain_flag}}
 
   count=replacement_count|plain=plain_flag}}
  
Line 342: Line 354:
 
         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
 
if source_str == '' or pattern == '' then
 
return source_str;
 
return source_str;
 
end
 
end
plain = str._getBoolean(plain);
+
plain = str._getBoolean( plain );
+
 
 
if plain then
 
if plain then
pattern = str.pattern_escape(pattern);
+
pattern = str._escapePattern( pattern );
replace = mw.ustring.gsub(replace, "%%", "%%%%"); --Only need to escape replacement sequences.
+
replace = mw.ustring.gsub( replace, "%%", "%%%%" ); --Only need to escape replacement sequences.
 
end
 
end
+
 
 
local result;
 
local result;
 
result = mw.ustring.gsub(source_str, pattern, replace, count);
 
 
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
  
function str.gsub(frame)
+
return result;
local params = {
 
[1] = { required = true, allow_empty = true },
 
[2] = { required = true, allow_empty = true },
 
[3] = { required = true, allow_empty = true },
 
[4] = { type = "number" },
 
}
 
 
local args = require("Module:parameters").process(frame.args, params)
 
 
return (mw.ustring.gsub(args[1], args[2], args[3], args[4]))
 
 
end
 
end
 
  
 
--[[
 
--[[
Line 386: Line 387:
 
]]
 
]]
  
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
 
end
  
function str.lower(frame)
+
--[[
local text = frame.args[1] or ''
+
escapePattern
return mw.ustring.lower(text)
+
 
 +
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
 
str.lc = str.lower
 
  
 
--[[
 
--[[
Line 407: Line 424:
 
we sometimes want to either preserve or remove that whitespace depending on the application.
 
we sometimes want to either preserve or remove that whitespace depending on the application.
 
]]
 
]]
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 _, 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
Line 420: Line 437:
 
new_args[arg] = value;
 
new_args[arg] = value;
 
end
 
end
+
 
 
return new_args;
 
return new_args;
 
end
 
end
Line 427: Line 444:
 
Helper function to handle error messages.
 
Helper function to handle error messages.
 
]]
 
]]
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 448: Line 465:
 
Helper Function to interpret boolean strings
 
Helper Function to interpret boolean strings
 
]]
 
]]
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'
Line 459: Line 476:
 
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
Line 468: Line 485:
  
 
--[[
 
--[[
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.pattern_escape(pattern_str)
+
function str._escapePattern( pattern_str )
local invoked = false
+
return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );
 
if type(pattern_str) == "table" then
 
if pattern_str.args then
 
local frame = pattern_str
 
invoked = true
 
 
if frame.args[1] then
 
pattern_str = frame.args[1]
 
else
 
pattern_str = frame:getParent().args[1]
 
end
 
else
 
error("First argument to pattern_escape should be a string, a number, or a frame object.")
 
end
 
elseif not (type(pattern_str) == "string" or type(pattern_str) == "number") then
 
error("First argument to pattern_escape should be a string or a number.")
 
end
 
 
if invoked then
 
local escaped = mw.ustring.gsub(pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1")
 
return escaped
 
else
 
return mw.ustring.gsub(pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1");
 
end
 
end
 
 
 
function str.count(text, pattern, plain)
 
if not (type(text) == "string" or type(text) == "number") then
 
error('The first argument to the function "count" must be a string or a number, not a ' .. type(text) .. '.')
 
end
 
 
if not (type(pattern) == "string" or type(pattern) == "number") then
 
error('The first argument to the function "count" must be a string or a number, not a ' .. type(text) .. '.')
 
end
 
 
if plain then
 
pattern = str.pattern_escape(pattern)
 
end
 
 
local _, count = mw.ustring.gsub(text, pattern, "")
 
 
return count
 
end
 
 
 
function str.plain_gsub(text, pattern, replacement)
 
local invoked = false
 
 
if type(text) == "table" then
 
invoked = true
 
 
if text.args then
 
local frame = text
 
 
local params = {
 
[1] = {},
 
[2] = {},
 
[3] = { allow_empty = true },
 
}
 
 
local args = require("Module:parameters").process(frame.args, params)
 
 
text = args[1]
 
pattern = args[2]
 
replacement = args[3]
 
else
 
error("If the first argument to plain_gsub is a table, it should be a frame object.")
 
end
 
else
 
if not (type(pattern) == "string" or type(pattern) == "number") then
 
error("The second argument to plain_gsub should be a string or a number.")
 
end
 
 
if not (type(replacement) == "string" or type(replacement) == "number") then
 
error("The third argument to plain_gsub should be a string or a number.")
 
end
 
end
 
 
pattern = str.pattern_escape(pattern)
 
 
if invoked then
 
text = mw.ustring.gsub(text, pattern, replacement)
 
return text
 
else
 
return mw.ustring.gsub(text, pattern, replacement)
 
end
 
end
 
 
 
function str.matchToArray(text, pattern)
 
local invoked = false
 
 
if type(text) == "table" then
 
invoked = true
 
 
if text.args then
 
local frame = text
 
 
local params = {
 
[1] = { required = true },
 
[2] = { required = true },
 
}
 
 
local args = require("Module:parameters").process(frame.args, params)
 
 
text = args[1]
 
pattern = args[2]
 
else
 
error("If the first argument to matchToArray is a table, it should be a frame object.")
 
end
 
else
 
if not (type(pattern) == "string" or type(pattern) == "number") then
 
error("The second argument to matchToArray should be a string or a number.")
 
end
 
end
 
 
local matches = {}
 
local i = 0
 
for match in mw.ustring.gmatch(text, pattern) do
 
i = i + 1
 
matches[i] = match
 
end
 
 
if i > 0 then
 
if invoked then
 
return table.concat(matches, ", ")
 
else
 
return matches
 
end
 
else
 
if invoked then
 
return ""
 
else
 
return nil
 
end
 
end
 
end
 
 
 
--[=[
 
Similar to gmatch, but it returns the count of the match in addition to the
 
list of captures, something like ipairs().
 
 
If the pattern doesn't contain any captures, the whole match is returned.
 
 
Invoke thus:
 
 
for i, whole_match in require("Module:string").imatch(text, pattern) do
 
[ do something with i and whole_match ]
 
end
 
 
or
 
 
for i, capture1[, capture2[, capture3[, ...]]] in require("Module:string").imatch(text, pattern) do
 
[ do something with i and capture1 ]
 
end
 
 
For example, this code
 
for i, whole_match in require("Module:string").imatch("a b c", "[a-z]") do
 
mw.log(i, whole_match)
 
end
 
will log
 
1 a
 
2 b
 
3 c
 
]=]
 
function str.imatch(text, pattern, pos, plain, use_basic_Lua_function)
 
local i = 0
 
pos = pos or 0
 
if not string.find(pattern, "%b()") then
 
pattern = "(" .. pattern .. ")"
 
end
 
local find = use_basic_Lua_function and string.find or mw.ustring.find
 
return function()
 
i = i + 1
 
local return_values = { find(text, pattern, pos, plain) }
 
local j = return_values[2]
 
 
if return_values[3] then
 
pos = j + 1
 
-- Skip the first two returned values, which are the indices of the
 
-- whole match.
 
return i, unpack(return_values, 3)
 
end
 
end
 
end
 
 
 
function str.escapebytes(s)
 
return (string.gsub(s,
 
'.',
 
function(char)
 
return ('\\%03d'):format(string.byte(char))
 
end))
 
end
 
 
 
function str.URIdecode(frame)
 
return mw.uri.decode(frame.args[1], frame.args[2] or "PATH")
 
 
end
 
end
  
 
return str
 
return str

Revision as of 14:03, 13 May 2019

Documentation for this module may be created at Module: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 = {}

--[[
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( '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 {{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( '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

--[[
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( 'String index out of range' );
	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

--[[
    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:
{{#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

--[[
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 = '<strong class="error">String Module Error: ' .. 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

--[[
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