Macros:Branching and Looping

This page details the branching and looping structures in MapTool. With the exception of the Block If statement, these are all roll options and should follow the general form for roll options:

[option1[,option2]: body]

These may be combined with other roll options (note that in some examples, they are combined with the Hidden Roll option (h) to hide the default output of the loop or branch).

Branching

Block IF() (introduced in version 1.3.b38)

Usage

[h: if(condition, true_value, false_value)]

Example

[h: val=12]
[h: if(val > 10, "Value is greater", "Value is less")]

Returns Value is greater.

IF Option (introduced in Version 1.3.b46)

This IF is a roll option (as mentioned above), but operates similarly to the block-style if.

Usage

[IF(condition): true_body; false_body]

or

[IF(condition): true_body]

Either the true_body or false_body will be used, depending on the value of condition. If the false_body is not given but the condition is false, then there is no output.

Example

[h:val=12]
[h,IF(val == 12): newVal=12*12]
New Value = [r:newVal]

Outputs New Value = 144.

SWITCH Option

SWITCH chooses among several options and executes code based on the switch expression.

Usage

[SWITCH(expression):
case case1: body1;
case case2: body2;
default: default_body]

Example

[h:powerType="at-will"]
[SWITCH(powerType):
case "at-will": "You may use this power as much as you like";
case "encounter": "You may only use this power once per encounter";
case "daily": "You may only use this power once per day"]

Outputs "You may use this power as much as you like"

Looping

COUNT Option

The COUNT option executes a statement a specified number of times, storing the number of the current iteration in a variable called roll.count.

Usage

[COUNT(num): body]
[COUNT(num, separator): body]

The roll.count variable will take on values from 0 to (number of loops - 1). The optional separator (default ", ") is printed between each iteration.

Example

[h:numHits=3]
[COUNT(numHits): Damage = Damage + 1d12]

Will iterate the Damage = Damage + 1d12 operation 3 times, separating the result of each iteration with the default separator (a comma).

FOR Option

Executes a statement for a number of iterations based on a start and end value.

Usage

[FOR(var, start, end): body]
[FOR(var, start, end, stepsize): body]
[FOR(var, start, end, stepsize, separator): body]

The var variable counts from start to end during the loop. The optional stepsize (default +1) is added to var at each iteration.

Example

[FOR(i,10,0,-2): "i is now " + i]

Counts down even numbers from 10 to 0.

FOREACH Option

Iterates over the contents of a string list in the format item1, item2, item3"

Usage

[FOREACH(var, list): body]
[FOREACH(var, list, output_separator): body]
[FOREACH(var, list, output_separator, list_separator): body]

Example

[h: enemyList="Orcs, Goblins, Ogres, Trolls"]
[FOREACH(enemy, enemyList, "<br>"): "You really hate " + enemy]

Outputs

You really hate Orcs
You really hate Goblins
You really hate Ogres
You really hate Trolls

WHILE Option

Repeatedly executes a statement until a condition becomes false.

Usage

[WHILE(condition): body]
[WHILE(condition, separator): body]

Example

[h:num=10]
[WHILE(num>=0): num = num-1]

Outputs 9,8,7,6,5,4,3,2,1

Code Execution

The CODE option is used in conjunction with looping / branching options to execute multiple statements within a single "block" of a loop or branch, allowing the creation of more complex loops and branches.

Usage

[CODE: { code_block }]

The code_block is a collection of text and macro code, enclosed in a single {} pair. Everything within the {} is treated as a single block for the purposes of any looping or branching options. NOTE: You cannot nest another pair of braces within the CODE block.

Example

[h:num=10]
[WHILE(num > 0), CODE:
{
  This is iteration [r:num] <br>
  There are [r:num-1] iterations left<br>
  [num=num-1]
}]

Outputs

This is iteration 5 There are 4 iterations left
4, This is iteration 4 There are 3 iterations left
3, This is iteration 3 There are 2 iterations left
2, This is iteration 2 There are 1 iterations left
1, This is iteration 1 There are 0 iterations left
0

NOTE: the digit output at the beginning of each line is an artifact of the WHILE loop's evaluation of num - since this roll does not have the h option active, that output is not suppressed.