Welcome to EndBASIC X.Y.Z.

    Type HELP for interactive usage information.
    For a guided tour, type: LOAD "DEMOS:/TOUR.BAS": RUN

Output from HELP:

    EndBASIC X.Y.Z
    Copyright 2020-2022 Julio Merino

    Project page at <https://www.endbasic.dev/>
    License Apache Version 2.0 <http://www.apache.org/licenses/LICENSE-2.0>

    Top-level help topics:

    >> Array functions
    >> Cloud access
    >> Console
    >> File system
    >> Graphics
    >> Hardware interface
    >> Interpreter
    >> Language reference
    >> Numerical functions
    >> Stored program
    >> String functions

    Type HELP followed by the name of a topic for details.
    Type HELP HELP for details on how to specify topic names.

Output from HELP ARRAY:

    Array functions

    >> LBOUND%    Returns the lower bound for the given dimension of the array.
    >> UBOUND%    Returns the upper bound for the given dimension of the array.

    Type HELP followed by the name of a symbol for details.

Output from HELP CLOUD:

    Cloud access

    The EndBASIC service is a cloud service that provides online file
    sharing across users of EndBASIC and the public.

    Files that have been shared publicly can be accessed without an account
    via the cloud:// file system scheme.  All you have to do is mount a
    user's cloud drive and then access the files as you would with your
    own.  For example:

    MOUNT "X", "cloud://user-123": DIR "X:"

    To upload files and share them, you need to create an account.  During
    account creation time, you are assigned a unique, persistent drive in
    which you can store files privately.  You can later choose to share
    individual files with the public or with specific individuals, at which
    point those people will be able to see them by mounting your drive.

    If you have any questions or experience any problems while interacting
    with the cloud service, please contact support@endbasic.dev.

    >> LOGIN     Logs into the user's account.
    >> LOGOUT    Logs the user out of their account.
    >> SHARE     Displays or modifies the ACLs of a file.
    >> SIGNUP    Creates a new user account interactively.

    Type HELP followed by the name of a symbol for details.

Output from HELP CONSOLE:

    Console

    The EndBASIC console is the display you are seeing: both the
    interpreter and the effects of all commands happen within the same
    console.  There is no separate output window as other didactical
    interpreters provide.  This unified console supports text and,
    depending on the output backend, graphics.  This help section focuses
    on the textual console; for information about graphics, run HELP
    GRAPHICS.

    The text console is a matrix of variable size.  The upper left position
    is row 0 and column 0.  Each position in this matrix contains a
    character and a color attribute.  The color attribute indicates the
    foreground and background colors of that character.  There is a default
    attribute to match the default settings of your terminal, which might
    not be a color: for example, in a terminal emulator configured with a
    black tint (aka a transparent terminal), the default color respects the
    transparency whereas color 0 (black) does not.

    If you are writing a script and do not want the script to interfere
    with other parts of the console, you should restrict the script to
    using only the INPUT and PRINT commands.

    Be aware that the console currently reacts poorly to size changes.
    Avoid resizing your terminal or web browser.  If you do resize them,
    however, restart the interpreter.

    >> CLS       Clears the screen.
    >> COLOR     Sets the foreground and background colors.
    >> INKEY$    Checks for an available key press and returns it.
    >> INPUT     Obtains user input from the console.
    >> LOCATE    Moves the cursor to the given position.
    >> PRINT     Prints a message to the console.

    Type HELP followed by the name of a symbol for details.

Output from HELP "FILE SYSTEM":

    File system

    The EndBASIC storage subsystem is organized as a collection of drives,
    each identified by a case-insensitive name.  Drives can be backed by a
    multitude of file systems with different behaviors, and their targets
    are specified as URIs.  Special targets include: memory://, which
    points to an in-memory read/write drive; and demos://, which points to
    a read-only drive with sample programs.  Other targets may be available
    such as file:// to access a local directory or local:// to access
    web-local storage, depending on the context.  The output of the MOUNT
    command can help to identify which targets are available.

    All commands that operate with files take a path.  Paths in EndBASIC
    can be of the form FILENAME.EXT, in which case they refer to a file in
    the current drive; or DRIVE:/FILENAME.EXT and DRIVE:FILENAME.EXT, in
    which case they refer to a file in the specified drive.  Note that the
    slash before the file name is currently optional because EndBASIC does
    not support directories yet.  Furthermore, if .EXT is missing, a .BAS
    extension is assumed.

    Be aware that the commands below must be invoked using proper EndBASIC
    syntax.  In particular, this means that path arguments must be
    double-quoted and multiple arguments have to be separated by a comma
    (not a space).  If you have used commands like CD, DIR, or MOUNT in
    other contexts, this is likely to confuse you.

    See the "Stored program" help topic for information on how to load,
    modify, and save programs.

    >> CD         Changes the current path.
    >> DIR        Displays the list of files on the current or given path.
    >> MOUNT      Lists the mounted drives or mounts a new drive.
    >> PWD        Prints the current working location.
    >> UNMOUNT    Unmounts the given drive.

    Type HELP followed by the name of a symbol for details.

Output from HELP GRAPHICS:

    Graphics

    The EndBASIC console overlays text and graphics in the same canvas.
    The consequence of this design choice is that the console has two
    coordinate systems: the character-based system, used by

    the commands described in HELP CONSOLE, and the pixel-based system,
    used by the commands described in this section.

    >> GFX_LINE     Draws a line from (x1,y1) to (x2,y2).
    >> GFX_PIXEL    Draws a pixel at (x,y).
    >> GFX_RECT     Draws a rectangle from (x1,y1) to (x2,y2).
    >> GFX_RECTF    Draws a filled rectangle from (x1,y1) to (x2,y2).
    >> GFX_SYNC     Controls the video syncing flag and/or forces a sync.

    Type HELP followed by the name of a symbol for details.

Output from HELP HARDWARE:

    Hardware interface

    EndBASIC provides features to manipulate external hardware.  These
    features are currently limited to GPIO interaction on a Raspberry Pi
    and are only available when EndBASIC has explicitly been built with the
    --features=rpi option.  Support for other busses and platforms may come
    later.

    >> GPIO_CLEAR    Resets the GPIO chip or a specific pin.
    >> GPIO_READ?    Reads the state of a GPIO pin.
    >> GPIO_SETUP    Configures a GPIO pin for input or output.
    >> GPIO_WRITE    Sets the state of a GPIO pin.

    Type HELP followed by the name of a symbol for details.

Output from HELP INTERPRETER:

    Interpreter

    >> CLEAR    Restores initial machine state but keeps the stored program.
    >> EXIT     Exits the interpreter.
    >> HELP     Prints interactive help.
    >> SLEEP    Suspends program execution.

    Type HELP followed by the name of a symbol for details.

Output from HELP LANG:

    Symbols (variable, array and function references):
        name?    Boolean (TRUE and FALSE).
        name#    Floating point (double).
        name%    Integer (32 bits).
        name$    String.
        name     Type determined by value or definition.

    Assignments and declarations:
        varref[(dim1[, ..., dimN])] = expr
        DIM varname[(dim1[, ..., dimN])] [AS BOOLEAN|DOUBLE|INTEGER|STRING]

    Expressions:
        a + b      a - b       a * b     a / b      a MOD b    -a
        a AND b    NOT a       a OR b    a XOR b
        a = b      a <> b      a < b     a <= b     a > b      a >= b
        (a)        varref
        arrayref(s1[, ..., sN])          funcref(a1[, ..., aN])

    Flow control:
        IF expr THEN: ...: ELSEIF expr THEN: ...: ELSE: ...: END IF
        FOR varref = expr TO expr [STEP int]: ...: NEXT
        WHILE expr: ...: WEND

    Misc:
        st1: st2    Separates statements (same as a newline).
        REM text    Comment until end of line.
        ' text      Comment until end of line.
        ,           Long separator for arguments to builtin call.
        ;           Short separator for arguments to builtin call.

Output from HELP NUMERICAL:

    Numerical functions

    >> ATN#         Computes the arc-tangent of a number.
    >> COS#         Computes the cosine of an angle.
    >> DEG          Sets degrees mode of calculation.
    >> DTOI%        Rounds the given double to the closest integer.
    >> ITOD#        Converts the given integer to a double.
    >> MAXD#        Returns the maximum number out of a set of doubles.
    >> MAXI%        Returns the maximum number out of a set of integers.
    >> MIND#        Returns the minimum number out of a set of doubles.
    >> MINI%        Returns the minimum number out of a set of integers.
    >> PI#          Returns the Archimedes' constant.
    >> RAD          Sets radians mode of calculation.
    >> RANDOMIZE    Reinitializes the pseudo-random number generator.
    >> RND#         Returns a random number in the [0..1] range.
    >> SIN#         Computes the sine of an angle.
    >> TAN#         Computes the tangent of an angle.

    Type HELP followed by the name of a symbol for details.

Output from HELP STORED:

    Stored program

    The EndBASIC interpreter has a piece of read/write memory called the
    "stored program".  This memory serves to maintain the code of a program
    you edit and manipulate right from the interpreter.

    The common flow to interact with a stored program is to load a program
    from disk using the LOAD command, modify its contents via the EDIT
    command, execute the program via the RUN command, and finally save the
    new or modified program via the SAVE command.

    Be aware that the stored program's content is lost whenever you load a
    program, exit the interpreter, or use the NEW command.  These
    operations will ask you to save the program if you have forgotten to do
    so, but it's better to get in the habit of saving often.

    See the "File system" help topic for information on where the programs
    can be saved and loaded from.

    >> DEL     Deletes the given program.
    >> EDIT    Interactively edits the stored program.
    >> LIST    Prints the currently-loaded program.
    >> LOAD    Loads the given program.
    >> NEW     Restores initial machine state and creates a new program.
    >> RUN     Runs the stored program.
    >> SAVE    Saves the current program in memory to the given filename.

    Type HELP followed by the name of a symbol for details.

Output from HELP STRING:

    String functions

    >> LEFT$     Returns a given number of characters from the left side of a string.
    >> LEN%      Returns the length of the string in expr$.
    >> LTRIM$    Returns a copy of a string with leading whitespace removed.
    >> MID$      Returns a portion of a string.
    >> RIGHT$    Returns a given number of characters from the right side of a string.
    >> RTRIM$    Returns a copy of a string with trailing whitespace removed.

    Type HELP followed by the name of a symbol for details.

Output from HELP CD:

    CD path$

    Changes the current path.

Output from HELP CLEAR:

    CLEAR

    Restores initial machine state but keeps the stored program.

    This command resets the machine to a semi-pristine state by clearing
    all user-defined variables and restoring the state of shared resources.
    These resources include: the console, whose color and video syncing bit
    are reset; and the GPIO pins, which are set to their default state.

    The stored program is kept in memory.  To clear that too, use NEW (but
    don't forget to first SAVE your program!).

Output from HELP CLS:

    CLS

    Clears the screen.

Output from HELP COLOR:

    COLOR [fg%][, [bg%]]

    Sets the foreground and background colors.

    Color numbers are given as ANSI numbers and can be between 0 and 255.
    If a color number is not specified, then the color is reset to the
    console's default.  The console default does not necessarily match any
    other color specifiable in the 0 to 255 range, as it might be
    transparent.

Output from HELP DEG:

    DEG

    Sets degrees mode of calculation.

    The default condition for the trigonometric functions is to use
    radians.  DEG configures the environment to use degrees until
    instructed otherwise.

Output from HELP DEL:

    DEL filename$

    Deletes the given program.

    The filename must be a string and must be a valid EndBASIC path.  The
    .BAS extension is optional but, if present, it must be .BAS.

    See the "File system" help topic for information on the path syntax.

Output from HELP DIR:

    DIR [path$]

    Displays the list of files on the current or given path.

Output from HELP EDIT:

    EDIT

    Interactively edits the stored program.

Output from HELP EXIT:

    EXIT [code%]

    Exits the interpreter.

    The optional code indicates the return value to return to the system.

Output from HELP GFX_LINE:

    GFX_LINE x1%, y1%, x2%, y2%

    Draws a line from (x1,y1) to (x2,y2).

    The line is drawn using the foreground color as selected by COLOR.

Output from HELP GFX_PIXEL:

    GFX_PIXEL x%, y%

    Draws a pixel at (x,y).

    The pixel is drawn using the foreground color as selected by COLOR.

Output from HELP GFX_RECT:

    GFX_RECT x1%, y1%, x2%, y2%

    Draws a rectangle from (x1,y1) to (x2,y2).

    The outline of the rectangle is drawn using the foreground color as
    selected by COLOR and the area of the rectangle is left untouched.

Output from HELP GFX_RECTF:

    GFX_RECTF x1%, y1%, x2%, y2%

    Draws a filled rectangle from (x1,y1) to (x2,y2).

    The outline and area of the rectangle are drawn using the foreground
    color as selected by COLOR.

Output from HELP GFX_SYNC:

    GFX_SYNC [enabled?]

    Controls the video syncing flag and/or forces a sync.

    With no arguments, this command triggers a video sync without updating
    the video syncing flag.  When enabled? is specified, this updates the
    video syncing flag accordingly and triggers a video sync if enabled? is
    TRUE.

    When video syncing is enabled, all console commands immediately refresh
    the console.  This is useful to see the effects of the commands right
    away, which is why this is the default mode in the interpreter.
    However, this is a *very* inefficient way of drawing.

    When video syncing is disabled, all console updates are buffered until
    video syncing is enabled again.  This is perfect to draw complex
    graphics efficiently.  If this is what you want to do, you should
    disable syncing first, render a frame, call GFX_SYNC to flush the
    frame, repeat until you are done, and then enable video syncing again.
    Note that the textual cursor is not visible when video syncing is
    disabled.

    WARNING: Be aware that if you disable video syncing in the interactive
    interpreter, you will not be able to see what you are typing any longer
    until you reenable video syncing.

Output from HELP GPIO_CLEAR:

    GPIO_CLEAR [pin%]

    Resets the GPIO chip or a specific pin.

    If no pin% is specified, resets the state of all GPIO pins.  If a pin%
    is given, only that pin is reset.  It is OK if the given pin has never
    been configured before.

Output from HELP GPIO_SETUP:

    GPIO_SETUP pin% mode$

    Configures a GPIO pin for input or output.

    Before a GPIO pin can be used for reads or writes, it must be
    configured to be an input or output pin.  Additionally, if pull up or
    pull down resistors are available and desired, these must be configured
    upfront too.

    The mode$ has to be one of "IN", "IN-PULL-DOWN", "IN-PULL-UP", or
    "OUT".  These values are case-insensitive.  The possibility of using
    the pull-down and pull-up resistors depends on whether they are
    available in the hardware, and selecting these modes will fail if they
    are not.

    It is OK to reconfigure an already configured pin without clearing its
    state first.

Output from HELP GPIO_WRITE:

    GPIO_WRITE pin% value?

    Sets the state of a GPIO pin.

    A FALSE value? sets the pin to low, and a TRUE value? sets the pin to
    high.

Output from HELP HELP:

    HELP [topic]

    Prints interactive help.

    Without arguments, shows a summary of all available top-level help
    topics.

    With a single argument, which may be a bare name or a string, shows
    detailed information about the given help topic, command, or function.
    Topic names with spaces in them must be double-quoted.

    Topic names are case-insensitive and can be specified as prefixes, in
    which case the topic whose name starts with the prefix will be shown.
    For example, the following invocations are all equivalent: HELP CON,
    HELP console, HELP "Console manipulation".

Output from HELP INPUT:

    INPUT ["prompt"] <;|,> variableref

    Obtains user input from the console.

    The first expression to this function must be empty or evaluate to a
    string, and specifies the prompt to print.  If this first argument is
    followed by the short `;` separator, the prompt is extended with a
    question mark.

    The second expression to this function must be a bare variable
    reference and indicates the variable to update with the obtained input.

Output from HELP LIST:

    LIST

    Prints the currently-loaded program.

Output from HELP LOAD:

    LOAD filename$

    Loads the given program.

    The filename must be a string and must be a valid EndBASIC path.  The
    .BAS extension is optional but, if present, it must be .BAS.

    Any previously stored program is discarded from memory, but LOAD will
    pause to ask before discarding any unsaved modifications.

    See the "File system" help topic for information on the path syntax.

Output from HELP LOCATE:

    LOCATE column%, row%

    Moves the cursor to the given position.

Output from HELP LOGIN:

    LOGIN username$ [password$]

    Logs into the user's account.

    On a successful login, this mounts your personal drive under the
    CLOUD:/ location, which you can access with any other file-related
    commands.  Using the cloud:// file system scheme, you can mount other
    people's drives with the MOUNT command.

    To create an account, use the SIGNUP command.

Output from HELP LOGOUT:

    LOGOUT

    Logs the user out of their account.

    Unmounts the CLOUD drive that was mounted by the LOGIN command.  As a
    consequence of this, running LOGOUT from within the CLOUD drive will
    fail.

Output from HELP MOUNT:

    MOUNT [drive_name$, target$]

    Lists the mounted drives or mounts a new drive.

    With no arguments, prints a list of mounted drives and their targets.

    With two arguments, mounts the drive_name$ to point to the target$.
    Drive names are specified without a colon at the end, and targets are
    given in the form of a URI.

Output from HELP NEW:

    NEW

    Restores initial machine state and creates a new program.

    This command resets the machine to a pristine state by clearing all
    user-defined variables and restoring the state of shared resources.
    These resources include: the console, whose color and video syncing bit
    are reset; and the GPIO pins, which are set to their default state.

    The stored program is also discarded from memory, but NEW will pause to
    ask before discarding any unsaved modifications.  To reset resources
    but avoid clearing the stored program, use CLEAR instead.

Output from HELP PWD:

    PWD

    Prints the current working location.

    If the EndBASIC path representing the current location is backed by a
    real path that is accessible by the underlying operating system,
    displays such path as well.

Output from HELP PRINT:

    PRINT [expr1 [<;|,> .. exprN]]

    Prints a message to the console.

    The expressions given as arguments are all evaluated and converted to
    strings.  Arguments separated by the short `;` separator are
    concatenated with a single space, while arguments separated by the long
    `,` separator are concatenated with a tab character.

Output from HELP RAD:

    RAD

    Sets radians mode of calculation.

    The default condition for the trigonometric functions is to use radians
    but it can be set to degrees with the DEG command.  RAD restores the
    environment to use radians mode.

Output from HELP RANDOMIZE:

    RANDOMIZE [seed%]

    Reinitializes the pseudo-random number generator.

    If no seed is given, uses system entropy to create a new sequence of
    random numbers.

    WARNING: These random numbers offer no cryptographic guarantees.

Output from HELP RUN:

    RUN

    Runs the stored program.

    This issues a CLEAR operation before starting the program to prevent
    previous leftover state from interfering with the new execution.

Output from HELP SAVE:

    SAVE [filename$]

    Saves the current program in memory to the given filename.

    The filename must be a string and must be a valid EndBASIC path.  The
    .BAS extension is optional but, if present, it must be .BAS.

    If no filename is given, SAVE will try to use the filename of the
    loaded program (if any) and will fail if no name has been given yet.

    See the "File system" help topic for information on the path syntax.

Output from HELP SHARE:

    SHARE filename$ [, acl1$, .., aclN$]

    Displays or modifies the ACLs of a file.

    If given only a filename$, this command prints out the ACLs of the
    file.

    Otherwise, when given a list of ACL changes, applies those changes to
    the file.  The acl1$ to aclN$ arguments are strings of the form
    "username+r" or "username-r", where the former adds "username" to the
    users allowed to read the file, and the latter removes "username" from
    the list of users allowed to read the file.

    You can use the special "public+r" ACL to share a file with everyone.
    These files can be auto-run via the web interface using the special URL
    that the command prints on success.

    Note that this command only works for cloud-based drives as it is
    designed to share files among users of the EndBASIC service.

Output from HELP SIGNUP:

    SIGNUP

    Creates a new user account interactively.

    This command will ask you for your personal information to create an
    account in the EndBASIC cloud service.  You will be asked for
    confirmation before proceeding.

Output from HELP SLEEP:

    SLEEP seconds%|seconds#

    Suspends program execution.

    Pauses program execution for the given number of seconds, which can be
    specified either as an integer or as a floating point number for finer
    precision.

Output from HELP UNMOUNT:

    UNMOUNT drive_name

    Unmounts the given drive.

    Drive names are specified without a colon at the end.

Output from HELP ATN:

    ATN#(n%|n#)

    Computes the arc-tangent of a number.

    The resulting angle is measured in degrees or radians depending on the
    angle mode as selected by the DEG and RAD commands.

Output from HELP COS:

    COS#(angle%|angle#)

    Computes the cosine of an angle.

    The input angle% or angle# is measured in degrees or radians depending
    on the angle mode as selected by the DEG and RAD commands.

Output from HELP DTOI:

    DTOI%(expr#)

    Rounds the given double to the closest integer.

    If the value is too small or too big to fit in the integer's range,
    returns the smallest or biggest possible integer that fits,
    respectively.

Output from HELP GPIO_READ:

    GPIO_READ?(pin%)

    Reads the state of a GPIO pin.

    Returns FALSE to represent a low value, and TRUE to represent a high
    value.

Output from HELP INKEY:

    INKEY$()

    Checks for an available key press and returns it.

    If a key press is available to be read, returns its name.  Otherwise,
    returns the empty string.  The returned key matches its name, number,
    or symbol and maintains case.  In other words, pressing the X key will
    return 'x' or 'X' depending on the SHIFT modifier.

    The following special keys are recognized: arrow keys (UP, DOWN, LEFT,
    RIGHT), backspace (BS), end or CTRL+E (END), enter (ENTER), CTRL+D
    (EOF), escape (ESC), home or CTRL+A (HOME), CTRL+C (INT), page up
    (PGUP), page down (PGDOWN), and tab (TAB).

    This function never blocks.  To wait for a key press, you need to
    explicitly poll the keyboard.  For example, to wait until the escape
    key is pressed, you could do:

    k$ = "": WHILE k$ <> "ESC": k = INKEY$(): SLEEP 0.01: WEND

    This non-blocking design lets you to combine the reception of multiple
    evens, such as from GPIO_INPUT?, within the same loop.

Output from HELP ITOD:

    ITOD#(expr%)

    Converts the given integer to a double.

Output from HELP LEFT:

    LEFT$(expr$, n%)

    Returns a given number of characters from the left side of a string.

    If n% is 0, returns an empty string.

    If n% is greater than or equal to the number of characters in expr$,
    returns expr$.

Output from HELP LEN:

    LEN%(expr$)

    Returns the length of the string in expr$.

Output from HELP LBOUND:

    LBOUND%(array[, dimension%])

    Returns the lower bound for the given dimension of the array.

    The lower bound is the smallest available subscript that can be
    provided to array indexing operations.

    For one-dimensional arrays, the dimension% is optional.  For
    multi-dimensional arrays, the dimension% is a 1-indexed integer.

Output from HELP LTRIM:

    LTRIM$(expr$)

    Returns a copy of a string with leading whitespace removed.

Output from HELP MIND:

    MIND#(expr#[, .., expr#])

    Returns the minimum number out of a set of doubles.

Output from HELP MINI:

    MINI%(expr%[, .., expr%])

    Returns the minimum number out of a set of integers.

Output from HELP MAXD:

    MAXD#(expr#[, .., expr#])

    Returns the maximum number out of a set of doubles.

Output from HELP MAXI:

    MAXI%(expr%[, .., expr%])

    Returns the maximum number out of a set of integers.

Output from HELP MID:

    MID$(expr$, start%[, length%])

    Returns a portion of a string.

    start% indicates the starting position of the substring to extract and
    it is 1-indexed.

    length% indicates the number of characters to extract and, if not
    specified, defaults to extracting

    until the end of the string.

Output from HELP PI:

    PI#()

    Returns the Archimedes' constant.

Output from HELP RIGHT:

    RIGHT$(expr$, n%)

    Returns a given number of characters from the right side of a string.

    If n% is 0, returns an empty string.

    If n% is greater than or equal to the number of characters in expr$,
    returns expr$.

Output from HELP RND:

    RND#(n%)

    Returns a random number in the [0..1] range.

    If n% is zero, returns the previously generated random number.  If n%
    is positive, returns a new random number.

    If you need to generate an integer random number within a specific
    range, say [0..100], compute it with an expression like DTOI%(RND#(1) *
    100.0).

    WARNING: These random numbers offer no cryptographic guarantees.

Output from HELP RTRIM:

    RTRIM$(expr$)

    Returns a copy of a string with trailing whitespace removed.

Output from HELP SIN:

    SIN#(angle%|angle#)

    Computes the sine of an angle.

    The input angle% or angle# is measured in degrees or radians depending
    on the angle mode as selected by the DEG and RAD commands.

Output from HELP TAN:

    TAN#(angle%|angle#)

    Computes the tangent of an angle.

    The input angle% or angle# is measured in degrees or radians depending
    on the angle mode as selected by the DEG and RAD commands.

Output from HELP UBOUND:

    UBOUND%(array[, dimension%])

    Returns the upper bound for the given dimension of the array.

    The upper bound is the largest available subscript that can be provided
    to array indexing operations.

    For one-dimensional arrays, the dimension% is optional.  For
    multi-dimensional arrays, the dimension% is a 1-indexed integer.

End of input by CTRL-D