Pharo Syntax on One Card

The whole language fits here. Everything else is objects and messages.

Literals — values you write directly

Kind	Examples
Integer / Float	42 -7 3.14 2r1010 "binary 10"
Fraction	3/4 "a real Fraction, not 0.75"
Character	$A $z $ "dollar + one char"
String	'hello' 'it''s' "double '' to escape"
Symbol	#count #+ "unique, interned"
Array (literal)	#(1 2 3 $a 'x' #sym)
Array (dynamic)	{ 1+1. 2 factorial } "evaluated"
Boolean / nil	true false nil

The three messages — this is the whole grammar

Type	Shape	Example	Precedence
Unary	receiver selector	5 factorial	1st (tightest)
Binary	receiver op arg	3 + 4	2nd
Keyword	recv k1: a1 k2: a2	arr at: 1 put: 9	3rd (loosest)

The one rule unary > binary > keyword, then left→right within a level. No arithmetic precedence. 2 + 3 * 4 → 20. Use ( ) to override. The selector of at:put: is the single name #at:put:.

The punctuation

Symbol	Means	Example
:=	assignment	count := 0
.	statement separator	a := 1. b := 2
;	cascade — more messages to the same receiver	c increment; increment; reset
^	return from method	^ count
"..."	comment	"this is a comment"
[ :x \| ... ]	block (a closure); `:x` is a parameter	[ :x \| x * x ]

Cascade vs. chain — the classic confusion

c increment; increment; count   "cascade: 3 messages to c. Value = last = count"
c increment increment count      "chain: count sent to (increment's result)"

A cascade’s receiver is the receiver of the first message before the first ;.

Defining a method (browser template)

incrementBy: anInteger          "selector + arg name = method header"
    count := count + anInteger   "body; no ^ means it returns self"

Blocks & conditionals are just messages

x > 0 ifTrue: [ 'pos' ] ifFalse: [ 'neg' ]    "ifTrue:ifFalse: sent to a Boolean"
3 timesRepeat: [ Transcript show: 'hi' ]
#(1 2 3) do: [ :each | Transcript show: each printString ]

This card is the compressed form of Lesson 0001. Ask your teacher (Claude) to expand any row into practice.