Difference between revisions of "String (API)"

Revision as of 04:42, 5 December 2012

The string API is a default Lua 5.1 API as defined here. Please list any non-working functions below.

Non-Working Functions

string.gmatch(string, pattern)

Using any quantifier other than + will cause it to hang if that quantifier applies to the whole pattern and that pattern does not match the whole string.

Examples:

"abcdef":gmatch("%a*")   -- Works
"abc=def":gmatch("%a*")   -- Hang
"abc=def":gmatch("%a.*")  -- Works
"abc=def":gmatch("[%a.]*")  -- Hang
"abc=def":gmatch("[^=]*")  -- Hang
"abc=def":gmatch("([^=]*)=?") -- Works (Note: This produces the same result as the above pattern should)
"abcdef":gmatch("[^=]*")  -- Works
"abc=def":gmatch("[^=]*=")  -- Works

string.sub / string.find

Both string.sub and string.find work on their own, but calling string.find on a string returned by string.sub will return the index of the character in the original string, not the sub string you are referencing.

Example:

local testString = "This is a sample string";
local testSubString = string.sub(testString,5);

local indexOfSample = string.find(testSubString,"sample");

indexOfSample is returned 11 instead of the expected 7

Concatenating a blank string onto the end of the string causes new memory to be allocated and works properly again

local testString = "This is a sample string";
local testSubString = string.sub(testString,5);

local indexOfSample = string.find(testSubString.."","sample");

This is also a problem with using string.find on command line arguments, as this returns the index in the full command path instead of the specific argument.