Module:String: Difference between revisions

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Created page with "--[[ 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 c..."
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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.
]]
]]
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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


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 );


local len = mw.ustring.len( s )
-- Convert negatives for range checking

if i < 0 then
-- Convert negatives for range checking
i = len + i + 1;
end
if i < 0 then
if j < 0 then
i = len + i + 1
end
j = len + j + 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' );
if i > len or j > len or i < 1 or j < 1 then
end
return str._error( 'String subset index out of range' )
if j < i then
end
return str._error( 'String subset indices out of order' );
end
if j < i then
return str._error( 'String subset indices out of order' )
end
return mw.ustring.sub( s, i, j )

return mw.ustring.sub( s, i, j )
end
end


--[[
--[[
This function implements that features of {{subr|s|skip|max}} and
This function implements that features of {{str sub old}} and is kept in order
is kept in order to maintain these older templates.
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


--[[
Uses only numbered paramameters to preserve spaces (caller may trim
_match
whitespaces by passing the parameter explicitly by numbering the
parameters).


This function returns a substring from the source string that matches a
Accepts negative values as relative to strng length.
specified pattern. It is exported for use in other modules


Usage:
No error is returned if attempting to read past end of string or
strmatch = require("Module:String")._match
before start of string.
sresult = strmatch( s, pattern, start, match, plain, nomatch )

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.

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


Currently does not parse and replace placeholders for nowiki tags.
]]
]]
-- This sub-routine is exported for use in other modules
function str.sublength( frame )
function str._match( s, pattern, start, match_index, plain_flag, nomatch )
local s = frame.args[1] or '';
if s == '' then
local skip = tonumber( frame.args[2] ) or 0;
return str._error( 'Target string is empty' )
local max = tonumber( frame.args[3] ) or 0;
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
local len = mw.ustring.len( s );
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)
-- convert negative values of max and skip as relative to string length
if max < 0 then
if match_index > 0 then
-- Forward search
max = len + max
for w in iterator do
end
match_index = match_index - 1
if skip < 0 then
if match_index == 0 then
skip = len + skip
result = w
end
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 ]
-- check boundaries to reduce the requested max
end
if skip < 0 then -- if before start of string
end
max = max + skip
skip = 0 -- skip can't underflow now
end
if max > len - skip then -- if past end of string
max = len - skip -- max can't overflow now
end
if max <= 0 then
return '' -- nothing left to return
end


if result == nil then
return mw.ustring.sub( s, skip + 1, skip + max )
if nomatch == nil then
return str._error( 'Match not found' )
else
return nomatch
end
else
return result
end
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.


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{{#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|match|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}}


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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.


Line 183: Line 241:


]]
]]
-- 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_flag, 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
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.


Line 277: Line 280:
]]
]]
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


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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.


Line 303: Line 306:
]]
]]
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


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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.
Line 349: Line 352:
]]
]]
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 );


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

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 387: Line 390:
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
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 count ~= nil then
if plain 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


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

--[[
count
This function counts the number of occurrences of one string in another.
]]
function str.count(frame)
local args = str._getParameters(frame.args, {'source', 'pattern', 'plain'})
local source = args.source or ''
local pattern = args.pattern or ''
local plain = str._getBoolean(args.plain or true)
if plain then
pattern = str._escapePattern(pattern)
end
local _, count = mw.ustring.gsub(source, pattern, '')
return count
end

--[[
endswith
This function determines whether a string ends with another string.
]]
function str.endswith(frame)
local args = str._getParameters(frame.args, {'source', 'pattern'})
local source = args.source or ''
local pattern = args.pattern or ''
if pattern == '' then
-- All strings end with the empty string.
return "yes"
end
if mw.ustring.sub(source, -mw.ustring.len(pattern), -1) == pattern then
return "yes"
else
return ""
end
end

--[[
join

Join all non empty arguments together; the first argument is the separator.
Usage:
{{#invoke:String|join|sep|one|two|three}}
]]
function str.join(frame)
local args = {}
local sep
for _, v in ipairs( frame.args ) do
if sep then
if v ~= '' then
table.insert(args, v)
end
else
sep = v
end
end
return table.concat( args, sep or '' )
end
end


Line 437: Line 519:
]]
]]
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 _, 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 457: Line 539:
]]
]]
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 478: Line 560:
]]
]]
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


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