Following are Lua keywords: and break do else elseif end false for function if in local nil not or repeat return then true until while; Following strings denote other tokens: if—then—else 1. There must be one or no else condition. Once an else if succeeds, none of the remaining else if's or else's will be tested. The syntax of an if...else if...else statement in Lua programming language is −. Also, the coming after or as a result of. The simplest form of conditional statement available in Lua is the "If" statement, which indicates that if one or more conditions are met, the following block of code will run. If statements take the following format This script will simply output the text "The variable is 1!". other closely related examples on the. In here, a switch statement would really be great to case through all GET["subfunction"] possibilities. The above example is saying that; "if age is eq… * / In the script above, the variable number is assigned the number 6 with an assignment statement. The core of a ternary is an if ... else statement. Lua doesn’t have true ternary operator but there is a way to mimic the behavior. The space creates a nested if statement that requires its own end keyword. Assumi… if a<0 then a = 0 end if a MAXLINES then showpage() line = 0 end When you write nested ifs, you can use elseif. "If" tells the code to do something if a condition is true or not. The else-part is optional. Past attendees on our training courses are welcome to use individual Local just means that the variable will only exist within the control structure. Let us write a simple Lua program. the examples they use to ensure that they are suitable for their In Lua, the only conditional calculation uses the if instruction. while true do wait (15) if p.Transparency == 1 and p.CanCollide == false then p.Transparency = 0 p.CanCollide = false end end That, with the old script, will now allow it to close on its own if it has been left open. function get_sets ()--Load and initialize the include file. a = 5b = 4if a < b then print("a is smaller than b")endif a == '1' then print("a is 1")elseif a == '2' then print("a is 2")elseif a == '3' then print("a is 3")else print("I have no idea what a is...")end while 1. --IMPORTANT: Make sure to also get the Mote-Include.lua file (and its supplementary files) to go with this.--Initialization function for this job file. and break do else elseif end false for function if in local nil not or repeat return then true until while The following strings denote other tokens: Lua is a case-sensitive language: and is a reserved word, but And and AND are two different, valid names. We learn about conditional branching via 'if', 'elseif', and 'else' in Lua. Lua is a free-form language. We have over 700 books in our library. Instead of nesting if statements you can use elseif. This replaces a switch-statement that Lua does not have. In case all conditions fail, then the action defined in the “else” clause is executed. The first thing I want to teach you is the "if" statement. When Lua precompiles a chunk, all its function bodies are precompiled too. Use pcall() (see below) to catch errors. This statement is a very basic, direct order to lua. Names (also called identifiers) in Lua can be any string of letters, digits, and underscores, not beginning with a digit and not being a reserved word. Remember there are only two values in the Lua world that are false: boolean false and nil. action. PICO-8 code comments are preceded by two hyphens (--) and go to the end of the line. Conditionals and loops example from a Well House Consultants training course. Perhaps the most Lua-ish syntax extension, introducing no new keywords, and preserving the current conditional syntax as much as possible, is something like these: x = if a then b elseif c then d else e end x = (if a then b elseif c then d else e end) x = (a then b elseif c then d else e) This is a simple if statement: The if statement can be a little confusing. This function instance (or closure) is the final value of the expression. You can learn more about this example on the training courses listed on this page, The while statement repeats execution as long as the condition is met. Training, Open Source Programming Languages, Special Tcl, Expect, Tk subjects / courses, "Conditionals and loops" module index page. Lua will go from top to bottom, stop at the first true condition it encounters, and execute its block of code. An if block can include multiple elseif blocks. Test a condition and execute the block as long … A condition still returns a Boolean output. While using if , else if , else statements, there are a few points to keep in mind −. When naming a variable or a table field, you must settle a valid induce for it. In case the “if” condition is false, then the “else if” condition is evaluated in a sequential manner till a match is found. This can be really useful in creating your own scripts. do -- This statement creates a new block and also a new scope. If all the expressions are evaluated as false and there is an else condition, the statement in the ELSE block is executed. False & nil are both considered as false, while everything else is considered as true. The following topics are discussed within the course: Variables; Conditional Statements (if, elseif, else) ... Let's go ahead and rewrite this function to do something else. Extended Capabilities. We can’t wait to see what you build with it. An if can have zero or one else's and it must come after any else if's. An if can have zero to many else if's and they must come before the else. If the Boolean expression evaluates to true, then the if block of code will be executed, otherwise else block of code will be executed. In Lua, if, elseif and else use then and end clauses to delimit the conditional code]] j = 45-- == for equality testing if j==45 then print ("yes") end An if statement can be followed by an optional else if...else statement, which is very useful to test various conditions using single if...else if statement. on which you'll be given a full set of training notes. Test a condition, execute the then part if the condition is true, otherwise execute the (optional) else part. The statements execute only if previous expressions in the if...end block are false. "and", "And" or "AND" are not the same. while Statement. When naming a variable or a table field, you must choose a valid name for it. Words if and then delineate the condition to be evaluated for truth or falsehood, while words then and end delineate the code to be run if the condition is true, assuming there are no else or elseif keywords, which are discussed later. You'll find a description of the topic and some They also support a multi-line syntax using double-brackets (--[[ ... ]]). It is to be noted that in Lua, zero will be considered as true. The syntax of an if...else statement in Lua programming language is − if (boolean_expression) then -- [ statement (s) will execute if the boolean expression is true --] else -- [ statement (s) will execute if the boolean expression is false --] end Loading... Autoplay When autoplay is enabled, a suggested video will automatically play next. end if. When the script is finished, the interpreter is no longer active. When you build and run the above code, it produces the following result. Also, the following keywords are reserved by Lua and can not be used as names: and, end, in, repeat, break, false, local, return, do, for, nil, then, else, function, not, true, elseif, if, or, until, while. This web site is written and maintained by, This is a sample program, class demonstration or answer from a. An if statement tests its condition and executes its then-part or its else-part accordingly. The only reason is that the only thinkable alternative (if-elseif) is ugly. 4.3.1 – if then else. Adding an elseif—then statement to an if—then structure lets you check if alternative conditions are true, assuming the preceding conditions are false. A function definition is an executable expression, whose value has type function. Good luck on your first if statement! Note that 0 or more elseif conditions can be included. Lua programming language assumes any combination of Boolean true and non-nil values as true, and if it is either Boolean false or nil, then it is assumed as false value.