Control#

Introduction#

The Control blocks in VEXcode manage the flow of a project by handling loops, conditions, delays, and stopping execution.

Below is a list of available blocks:

  • wait – Pauses execution for a specific duration.

  • wait until – Pauses execution until a specified condition is met.

  • repeat – Repeats enclosed blocks a specific number of times.

  • forever – Repeats enclosed blocks indefinitely.

  • repeat until – Repeats enclosed blocks until a condition is met.

  • while – Repeats enclosed blocks while a condition remains true.

  • if – Runs enclosed blocks if a condition is true.

  • if / else – Runs one set of blocks if a condition is true, otherwise runs another.

  • if / else if / else – Runs different sets of blocks depending on multiple conditions.

  • break – Exits a repeat, forever, repeat until, or while loop immediately.

  • stop project – Ends the execution of the project.

wait#

The wait block pauses for a specific amount of time before moving to the next block.

wait stack block#
    wait (1) seconds

Parameters

Description

time

The amount of time to wait, as a positive integer or decimal in seconds.

Example

When started, moves forward for one second, then stops all movement.#
    when started
    [Move to the left, then the right after one second.]
    increment [arm v] position by x:[100] y:[0] z:[0] [mm v] ▶
    wait (1) seconds
    increment [arm v] position by x:[-100] y:[0] z:[0] [mm v] ▶

wait until#

The wait until block pauses execution until a specified condition is met before proceeding to the next block.

wait until stack block#
    wait until <>

Parameters

Description

condition

The condition that must be met before moving on to the next block.

repeat#

The repeat block runs the blocks inside it a set number of times.

repeat c block#
    repeat [10]
    end

Parameters

Description

times

A whole number that sets how many times the repeat block runs.

Example

    when started
    [Move in a square pattern.]
    repeat [4]
        increment [arm v] position by x:[2] y:[0] z:[0] [inches v] ▶
        increment [arm v] position by x:[0] y:[2] z:[0] [inches v] ▶
        increment [arm v] position by x:[-2] y:[0] z:[0] [inches v] ▶
        increment [arm v] position by x:[0] y:[2] z:[0] [inches v] ▶
    end

forever#

The forever block keeps running the blocks inside it again and again without stopping.

forever c block#
    forever
    end

Parameters

Description

This block has no parameters.

Example

When started, continuously moves in a square path by moving forward 50 mm and turning right 90 degrees in an infinite loop.#
    when started
    [Move in a square path forever.]
    forever
        increment [arm v] position by x:[2] y:[0] z:[0] [inches v] ▶
        increment [arm v] position by x:[0] y:[2] z:[0] [inches v] ▶
        increment [arm v] position by x:[-2] y:[0] z:[0] [inches v] ▶
        increment [arm v] position by x:[0] y:[2] z:[0] [inches v] ▶
    end

repeat until#

The repeat until block executes the enclosed blocks repeatedly while the condition evaluates as False.

repeat until block#
    repeat until <>
    end

Parameters

Description

condition

An expression or variable that is evaluated before each iteration. If it evaluates as:

  • False - The loop continues
  • True - The loop stops

Example

When started, keeps all LEDs red until the screen is pressed, then turns them off.#
    when started
    [Increment along the x-axis until it's no longer possible.]
    repeat until <not <[arm v] increment position by x:[100] y:[0] z:[0] [mm v] ?>>
        increment [arm v] position by x:[100] y:[0] z:[0] [mm v] ▶
    end
    set [arm v] to control stopped

while#

The while block executes the enclosed blocks repeatedly while the condition evaluates as True.

while c block#
    while <>
    end

Parameters

Description

condition

An expression or variable that is evaluated before each iteration. If it evaluates as:

  • True - The loop continues
  • False - The loop stops

Example

A stack of blocks that begins with a when started block, followed by a comment block reading Display the time after 2 seconds have passed. A wait until block pauses execution until the timer reaches or exceeds two seconds. Once this condition is met, a print block displays the timer value on the screen.#
when started
[Display the 6-Axis Arm's position as it moves.]
move [arm v] to position x:(-100) y:(200) z:(100) [mm v] ◀ and don't wait
while <not <[arm v] is done moving?>>
print ([arm v] position [y v] in [mm v]) on console ◀ and set cursor to next row
wait [0.25] seconds

if#

The if block executes the enclosed block of code if the condition evaluates as True.

if block#
    if <> then
    end

Parameters

Description

condition

An expression or variable that is evaluated when the statement runs. If it evaluates as:

  • True - The code inside the if block executes
  • False - The block is skipped

Example

when started
[Check if the 6-Axis Arm can move to a position.]
if <not <[arm v] move to position x:[0] y:[0] z:[0] [mm v] ?>> then
print [The 6-Axis Arm can't move to this position.] ◀ and set cursor to next row

if / else#

The if / else block determines which enclosed block of code runs based on whether the condition evaluates as True or False.

if then else block#
    if <> then
    else
    end

Parameters

Description

condition

An expression or variable that is evaluated when the statement runs. If it evaluates as:

  • True - The code inside the if block executes
  • False - The code inside the else block executes instead

Example

when started
[Check if the 6-Axis Arm can or can't move to a position.]
if <not <[arm v] move to position x:[100] y:[100] z:[100] [mm v] ?>> then
print [The 6-Axis Arm can't move to this position.] on console ◀ and set cursor to next row
else
print [The 6-Axis Arm can move to this position.] on console ◀ and set cursor to next row

if / else if / else#

The if / else if / else block structure selects which enclosed block of code runs based on conditions:

  • if runs its block of code if the condition evaluates as True.

  • else if checks additional conditions only if all previous conditions evaluated as False. Multiple else if statements can be used.

  • else runs its block of code only if none of the previous conditions evaluated as True.

if else if else block#
    if <> then
    else if <> then
    else 
    end

Parameters

Description

condition

An expression or variable that is evaluated when the statement runs. The first condition that evaluates as:

  • True - Determines which block of code executes
  • False - If none are True, the else block of code runs

Example

when started
[Move until the 6-Axis Arm is at the corner of the tile.]
if <[arm v] increment position by x:[50] y:[0] z:[0] [mm v] ?> then
increment [arm] position by x:[50] y:[0] z:[0] [mm v] ▶
else if <[arm v] increment position by x:[0] y:[50] z:[0] [mm v] ?> then
increment [arm] position by x:[0] y:[50] z:[0] [mm v] ▶
else
print [The 6-Axis Arm has reached the corner.] on console ◀ and set cursor to next row

break#

The break block exits a loop immediately.

break stack block#
    break

Parameters

Description

This block has no parameters.

stop project#

The stop project block ends a running project.

stop project block#
    stop project

Parameters

Description

This block has no parameters.