ADD var, expr [, min TO max] [CLAMP]

The ADD statement is used to increment the value of a numeric variable by a specified amount. In other words, it is like adding one number to another.

The basic syntax take the var to which you want to add a value and the expr as the expression you want to add to the variable. The full syntax takes also two additional parameters: min and max, that are the minimum and maximum value that the variable can take after the increment. In other words, the var is incremented, but its value is “squeezed” between min and max. If the result of the addition had been greater than max, the level would be put to min. Otherwise, if the var si less than min, the variable will be set to max.

It is possible to “clamp” the value of var instead of turn around the limits. By using the CLAMP keyword, you can change the behaviour: var will be assigned to min if a value is lesser than min and to max if a value is greater than max.

The purpose of this second syntax is to prevent a variable from taking invalid value for your program. It can also help to simulating real-world systems: for example, in a game you can limit a character's life between 0 and 100. This instruction can also help to create special effects: you can create bouncing or wrapping effects, by making a variable “bounce” between two values. In videogames, the typical use is to limit the maximum score in a game, or to preventing a difficulty level from exceeding a certain value.

  ADD y,10
  ADD x,42,1 TO 100 CLAMP

See also the following example files:

• maths_fast_02.bas

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If you have encountered a problem using this command, if you think there is a bug or the explanation is unclear, please open an issue for this keyword on GitHub. Thank you!