LOOP is a set of modules with functions that help doing object-oriented programming (OOP) in Lua.Much like the Table Manipulation module from the Standard Libraries provides functions to manipulate sequences (e.g. insert or remove elements), LOOP modules provide functions to manipulate objects (e.g. get its class) and classes (e.g. define its superclass).LOOP is based on common solutions adopted by programmers doing OOP in Lua with focus in simplicity and efficiency.

In the repeat–until loop, the inner block does not end at the until keyword, but only after the condition. So, the condition can refer to local variables declared inside the loop block. The goto statement transfers the program control to a label. For syntactical reasons, labels in Lua are considered statements too.
Like for loops, the while loop can also be used an expression. Additionally, for a function to return the accumulated value of a while loop, the statement must be explicitly returned. A continue statement can be used to skip the current iteration in a loop.

The repeat-untilloop is just like the repeat-until loop in Pascal or Delphi, and is reminiscent of the do-while loop in C. The generic for loopis somewhat similar to Perl's foreach loop, in that every element of a group gets done exactly once, and things get.

LOOP modules are intended to aid the programmer to perform common tasks using well known solutions for OOP in Lua.Objects and classes created with LOOP usually interoperate well with other objects and libraries due to this adoption of well known solutions.

Lua For Loop Example

Note: Are you new to Lua? Then read this.

Lua For Statement

This first edition was written for Lua 5.0. While still largely relevant for later versions, there are some differences.
The fourth edition targets Lua 5.3 and is available at Amazon and other bookstores.
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Programming in Lua

Part I. The LanguageChapter 4. Statements

4.3.4 – Numeric for

Lua C For Loop Tutorial

The for statement has two variants:the numericfor and the genericfor.

A numeric for has the following syntax:That loop will execute something for each value of varfrom exp1 to exp2, using exp3 as the stepto increment var.This third expression is optional;when absent, Lua assumes one as the step value.As typical examples of such loops, we have

Lua For Loop Syntax

The for loop has some subtleties that you should learnin order to make good use of it.First, all three expressions are evaluated once, before the loop starts.For instance, in the first example, f(x) is called only once.Second, the control variable is a local variable automaticallydeclared by the for statementand is visible only inside the loop.A typical mistake is to assume that the variable still exists afterthe loop ends:If you need the value of the control variable after the loop(usually when you break the loop),you must save this value into another variable:Third, you should never change the value of the control variable:The effect of such changes is unpredictable.If you want to break a for loopbefore its normal termination, use break.