Arcweave has its own scripting language, **arcscript**, with basic scripting capabilities. You can use arcscript inside element content as arcscript segments and in branches as `if/elseif/else`

conditions.

In this chapter, we will discuss the syntax of arcscript segments only. Branches are covered in their own chapter.

{primary} Any variable you use in arcscript segments or branches must first be declared in Global variables.

Arcscript segments currently support only **assignment** and **conditional** statements.

Assignment statements are of the form: `variable = expression`

.

Examples:

`x = 5`

`x = y + 5`

`name = "Tim"`

`has_key = true`

Arcscript also supports **addition**, **subtraction**, **multiplication** and **division assignments** using the operators: `+=`

, `-=`

, `*=`

, `/=`

respectively.

Example:

` ``x += 2`

Conditional statements are of the form: `if.../elseif.../else/endif`

. Inside conditional statements, you may have:

- other statements (assignments or conditionals).
- text content.

Example of a conditional statement containing an assignment:

`if x == 5`

`y = 4`

`endif`

Examples of a conditional statement containing text:

`if wielding_shield`

The knight is wielding a large shield.`endif`

`if hasKey`

You unlock the door!`doorUnlocked = true`

`else`

You cannot open the door.`endif`

Example of using `elseif`

for multiple outcomes:

`if age >= 18`

Look at you! All grown up!`type = "adult"`

`elseif age > 0`

You are not an adult yet.`type = "child"`

`else`

Are you sure you haven't been born yet?`type = "unborn"`

`endif`

Arcsript supports the creation of expressions using the following arithmetic operators:
`+`

, `-`

, `*`

, `/`

and `(`

, `)`

. Expressions may combine literals, function calls and variables.

Conditions in **Arcscript** may be formed by using the following conditional operators:
`==`

(or `is`

), `!=`

(or `is not`

), `>`

, `>=`

, `<`

, `<=`

.

Combining conditions may be achieved by using the following logical operators:
`&&`

(or `and`

), `||`

(or `or`

), `!`

(or `not`

).

The functions that are currently supported in Arcscript:

Function | Returns... |
---|---|

abs(n) | ...the absolute value of a number |

sqr(n) | ...the square of a number |

sqrt(n) | ...the square root of a number |

random() | ... a random decimal between (and including) 0 and (excluding) 1, i.e. in `[0, 1)` |

reset(v1, v2, ...) | ... has no return value - resets the given variables to their initial value |

resetAll(v1, v2, ...) | ... has no return value - resets all variables, except the given ones, to their initial value |

roll(m, n) | ... a roll of an (n) number of (m)-sided dice (see below) |

show(e1, e2, ...) | ... the evaluation and concatenation of its argument expressions (see below) |

The `roll(m, n)`

function simulates polyhedral die rolls from the classic tabletop RPGs.

Roll takes 2 integer numbers as its arguments:

`m`

: the number of sides of the rolled die.`n`

: the number of dice rolled.

The function returns a random integer between (and including both) `n`

and `n*m`

, i.e. `[n, n*m]`

.

{success} If n = 1 you can omit the second argument and simply type roll(m).

For example, rolling for a number from 1 to 12:

` ``damage = roll(12)`

Example of rolling 3d6 (3 six-sided dice) for ability scores in D&D:

` ``dexterity = roll(6, 3)`

Example of a dynamic use, where the player suffers damage from 1 to `max_damage`

:

` ``player_hp = player_hp - roll(max_damage)`

But the `roll(m, n)`

function can also be used in a conditional statement:

`if roll(max_damage) > player_hp`

Oops... This isn't good...`endif`

The `show(e1, e2, ...)`

function renders its arguments and concatenates them as one string.

For example, the following:

` ``show("Your score is ", score, "/", max_score, ".")`

... for `score == 3`

and `max_score == 256`

returns:

> Your score is 3/256.

You can use the `show(e1, e2, ...)`

function in combination with text content, in elements. For example:

`if roll(max_damage) > player_hp`

Oops... This isn't good...You have died. In this game, you scored`show(score, " out of ", max_score, ".")`

`endif`

When a script has a compile-time error, this is denoted by an **exclamation mark symbol**, at the lower right corner of the container element.

{success} Hover your mouse cursor over the symbol to get more info on what the error is about.