Module:String: Difference between revisions
add nomatch option to str.match
(Undo revision 652101 (it's breaking {Str sub}} and {{git}}) by Dragons flight (talk)) |
m>WOSlinker (add nomatch option to str.match) |
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--[[ | |||
This module is intended to provide access to basic string functions. | |||
function | Most of the functions provided here can be invoked with named parameters, | ||
local | unnamed parameters, or a mixture. If named parameters are used, Mediawiki will | ||
local | automatically remove any leading or trailing whitespace from the parameter. | ||
local | Depending on the intended use, it may be advantageous to either preserve or | ||
if | remove such whitespace. | ||
local first = | |||
Global options | |||
return string. | 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 | else | ||
return | 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 | 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 | |||
--[[ | |||
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 | return str |