Print Char

One character at a time — but any of them: an arrow, a box-drawing line or the copper icon

easyYou need: The text buffer, Content constants

printchar appends one character to the buffer. Not a string, not a number — exactly one character, given by its code.

steptick 0

Sensor0

=

 in

Print Char1

char 

Print2

Print3

Print Char4

char 

Print Char5

char 

Print Flush6

Wait7

@counter0number

coppernullnull

textBuffer—string

Press “run”. Under the message block you get the copper icon, the number 120 and an upward arrow: the icon came from printchar @copper, the arrow from printchar 8593.

A character by code

The number is a character’s code in UTF-16: printchar 65 gives A, printchar 97 gives a, printchar 32 gives a space. A fractional number is truncated down to a whole code.

Next to the field in the block there is a pencil: it opens a table of printable characters from 32 to 126, so you do not have to hunt for codes on the internet. Anything above that is typed as a number.

Note

Box drawing is the only way mlog draws “graphics” in text: arrows ↑ (8593), ↓ (8595), lines ─ (9472) and │ (9474), a tick ✓ (10003). One instruction per character, but you end up with a table inside a message block.

A content character is an icon

printchar @copper puts the copper character into the buffer, and in the caption it looks like an icon rather than letters. Liquids, blocks and unit types work the same way.

The trick behind it: every item has a character code of its own, but there is no glyph for it in the font — the game draws a picture from the atlas in its place. That is why an icon cannot be typed on a keyboard, and printchar is the only way to get one.

Silent failure

Anything that is not an item, a liquid, a block or a unit type is silently skipped by printchar: a string, a building, a team, emptiness — nothing is added, and the buffer stays as it was.

The building case is especially annoying: printchar container1 looks meaningful and does nothing. A block’s icon comes from its type — printchar @container.

What it is for

Task	How
an item’s icon in a caption	printchar @copper
an arrow or a tick	printchar 8593, printchar 10003
a line break	easier as a string, print "\n"
a long text	not needed: that is print

A board with icons reads noticeably faster than one with words — especially when there are several items and the line updates on the fly.

Remember

• printchar adds exactly one character by its UTF-16 code.
• A fractional code is truncated down.
• An item, a liquid, a block and a unit type give their own icon.
• Everything else — a string, a building, a team, emptiness — is skipped in silence.

Task

Replace @copper with @container and run it: the copper icon becomes the container icon. Then try container1 — the icon disappears entirely, though the line looks almost the same.

Then change 8593 to 10003: the arrow becomes a tick. Character codes can be found in any Unicode table, and printable ones are easier to pick with the pencil next to the field.