Libraries ​

c0de comes with ready-made functions. A few are built in and always there. The others are grouped in libraries, which you load with an INCLUDE line.

Calling them ​

All these functions are called with CALL, like your own functions. Built-in functions use their plain name. Library functions use their full name, like c0de/strings/MID.

CALL c0de/strings/MID
    PARAMETER text name ;
    PARAMETER start 2 ;
    PARAMETER length 3 ;
    RESULT result part

A function with one result names it result. Positions in texts and lists start at 0.

Changing values ​

Functions get copies of their parameters. A function that changes a text, list or hash gives back the changed copy as result.

To change a variable, use it both as parameter and as result target:

CALL INSERT
    PARAMETER array list ;
    PARAMETER index 0 ;
    PARAMETER value 0 ;
    RESULT result list

Including libraries ​

INCLUDE lines come right after the NOOP in line 1, before any other statement. They start at x=5, like the PROGRAM line.

PROGRAM math
NOOP
INCLUDE c0de/math
INCLUDE c0de/strings

The LABEL dialog next to an INCLUDE block lists all libraries you can choose from.

Built-in functions ​

These work without INCLUDE:

• LEN: the length of a text, array or hash
• HAS_KEY: true if a hash has a key
• REMOVE: an array or hash without one element
• INSERT: an array with a new element at a position
• CLEAR: an empty array or hash
• SWAP: swaps two values
• RAISE: raises your own error, code 1000 or higher

c0de/math ​

Numbers and random values. It also has the constant c0de/math/PI.

• ABS, SGN: size and sign of a number
• SQR, EXP, LOG: square root, e to the power, logarithm
• SIN, COS, TAN, ATN: angles in radians
• INT, FIX, ROUND: turn a FLOAT into an INTEGER
• TO_FLOAT: turn an INTEGER into a FLOAT
• DIV: whole-number division
• RANDOM: a random FLOAT from 0 to below 1
• RANDOMIZE: set the start of the random numbers

Rounding ​

INT rounds down: -12.85 gives -13. FIX just cuts off the decimals: -12.85 gives -12. ROUND goes to the nearest whole number. A .5 goes to the even neighbor, so 12.5 gives 12 and 13.5 gives 14.

CALL c0de/math/ROUND
    PARAMETER value 12.5 ;
    RESULT result rounded

c0de/strings ​

Text and characters:

• LEFT, RIGHT, MID: parts of a text
• REPLACE: overwrite part of a text
• INSTR: find a text in a text, -1 if not found
• UCASE, LCASE: upper and lower case
• SPACE, FILL: a text of spaces or of one character
• ASC, CHR: characters and their code numbers

Conversions:

• STR: any simple value as text
• FORMAT: a value as text in a format you choose
• VAL: a text as a number
• HEX, OCT: a number in hexadecimal or octal

FORMAT ​

FORMAT turns a value into text with a format string. %d is a whole number, %f a decimal number and %s any value. A number between % and the letter sets the width.

• [%4d] turns 42 into [ 42]
• %05d turns 42 into 00042
• %.2f turns 3.14159 into 3.14
• %,d turns 1234567 into 1,234,567

For TIME values, %tF gives the date and %tT the time, like 2026-10-19 and 14:05:09. Many more codes exist, such as %tA for the name of the weekday.

JSON and YAML ​

c0de/strings can also turn any value into JSON or YAML text with TO_JSON and TO_YAML. FROM_JSON and FROM_YAML read such text back into a variable.

TAG blocks at the end of a VARIABLE line or a struct element set the key names used in JSON or YAML.

c0de/time ​

Real-world time and date, in the time zone of the server:

• NOW: the current time as a TIME value
• YEAR, MONTH, DAY: parts of the date
• HOUR, MINUTE, SECOND, MILLISECOND: parts of the time
• WEEKDAY: 1 for Monday up to 7 for Sunday
• WEEK: the week of the year
• TIMER: seconds since midnight
• SLEEP: wait for a number of game ticks

The date and time functions use the current time, or a TIME value you pass as time. SLEEP waits between 1 and 72000 ticks.

c0de/minecraft ​

This library lets programs touch the world around the trigger block:

• TICKS: the game time

• BEEP, SOUND: play notes like a note block

• SAY: write a message to the chat

• GET_BLOCK: read a block and its redstone power

• GET_INVENTORY: read the items in a chest or other container

• GET_LEVER, SET_LEVER: read or flip levers

• GET_BUTTON, PRESS_BUTTON: read or press buttons

• GET_PRESSURE_PLATE: read pressure plates

• GET_OPEN, SET_OPEN: doors, trapdoors and fence gates

• FIND_ENTITIES: find mobs and items nearby

Changing the world ​

Some functions change the world more:

• MOVE_ITEMS, DELETE_ITEMS: move or remove items in containers
• PLACE_BLOCK, REMOVE_BLOCK: place or break blocks
• SPAWN_ITEM, SPAWN_ENTITY: create items and mobs
• TELEPORT: move an entity

Positions are given as a c0de/minecraft/POSITION struct with x, y, z and an optional dimension. Programs can never change the blocks on the sheets of the c0de dimension.

Owner and permissions ​

Programs act on behalf of the owner of the trigger block. The world-changing functions above only work if the owner is an operator, or if the server allows them in the file config/c0de.properties.

Otherwise they raise PERMISSION_DENIED. Players can only be teleported if the owner is an operator.

Two functions work for every owner, because they only do what a player can do:

• MINE_BLOCK breaks a block with the best tool from a chest (tool_inventory). The tool wears out and it takes as long as for a player. The drops go into another chest (output_inventory), or fall on the ground. If that chest is full, it raises INVENTORY_FULL.
• PLACE_BLOCK with the parameter inventory takes the block from a chest. If the chest doesn't contain it, it raises ITEM_MISSING.

Making music ​

A short example: play a bell note at the trigger block.

CALL c0de/minecraft/SOUND
    PARAMETER note 12 ;
    PARAMETER instrument "bell" ;

note goes from 0 to 24, like the clicks on a note block. Without instrument, SOUND uses the harp.