How to break a big lua string into small ones
Have you tried the string.sub(s, i [, j]) function. You may like to look here:
http://lua-users.org/wiki/StringLibraryTutorial
I'd put all chunks in a table and use table.concat on it. This avoids the creation of new strings at every concatenation. for example (without counting overhead for strings in Lua):
-- bytes used
foo="1234".. -- 4 = 4
"4567".. -- 4 + 4 + 8 = 16
"89ab" -- 16 + 4 + 12 = 32
-- | | | \_ grand total after concatenation on last line
-- | | \_ second operand of concatenation
-- | \_ first operand of concatenation
-- \_ total size used until last concatenation
As you can see, this explodes pretty rapidly. It's better to:
foo=table.concat{
"1234",
"4567",
"89ab"}
Which will take about 3*4+12=24 bytes.
According to Programming in Lua 2.4 Strings:
We can delimit literal strings also by matching double square brackets [[...]]. Literals in this bracketed form may run for several lines, may nest, and do not interpret escape sequences. Moreover, this form ignores the first character of the string when this character is a newline. This form is especially convenient for writing strings that contain program pieces; for instance,
page = [[
<HTML>
<HEAD>
<TITLE>An HTML Page</TITLE>
</HEAD>
<BODY>
<A HREF="http://www.lua.org">Lua</A>
[[a text between double brackets]]
</BODY>
</HTML>
]]
This is the closest thing to what you are asking for, but using the above method keeps the newlines embedded in the string, so this will not work directly.
You can also do this with string concatenation (using ..):
value = "long text that" ..
" I want to carry over" ..
"onto multiple lines"
Most answers here solves this issue at run-time and not at compile-time.
Lua 5.2 introduces the escape sequence \z to solve this problem elegantly without incurring any run-time expense.
> print "This is a long \z
>> string with \z
>> breaks in between, \z
>> and is spanning multiple lines \z
>> but still is a single string only!"
This is a long string with breaks in between, and is spanning multiple lines but still is a single string only!
\z skips all subsequent characters in a string literal1 until the first non-space character. This works for non-multiline literal text too.
> print "This is a simple \z string"
This is a simple string
From Lua 5.2 Reference Manual
The escape sequence '\z' skips the following span of white-space characters, including line breaks; it is particularly useful to break and indent a long literal string into multiple lines without adding the newlines and spaces into the string contents.
1: All escape sequences, including \z, work only on short literal strings ("…", '…') and, understandably, not on long literal strings ([[...]], etc.)