Syntax: consists of s-expressions. The first element of the s-expression tells the compiler what to do with it.

Builtin atoms:
true    true boolean
false   false boolean

Builtin types:
var         the basic data type
void        used to indicate that function or expression returns nothing
ptr<x>      pointer to x
fun<x>      function returning x
arr<x><n>   array with elements of type x. Has n elements. n must be a number literal

S-expressions:
(first-term ...)
so for example: 1+2+3 is written as (+ 1 2 3)



+       addition  (+ and - have overloading behavior for pointers)
-       subtraction (inverse if only one element after -)
*       multiplication
/       division
mod     modulo
join    join as strings

not     boolean not
>       greater than
<       less than
>=      greater or equal to 
<=      less or equal to
=       equal
!=      not equal

get     get element of struct array or pointer
adr     get pointer to element
drf     dereference pointer
iget    (indirectly) get element

local   define a local variable of a given type
static  define a static variable of a given type
set     overwrite the value of something in memory
change  change value of variable by x

if      general-purpose if statement. 
        Can be used like the ternary operator if there is a default case.
progn   do everything inside as one expression. Returns result of last expression.

loop    'forever' loop
break   exit current loop
until   repeat-until loop
while   while loop
for     c-like for loop

defun   define a function and its output, input and body
return  return from a function
***     call function ***, assuming that *** is the name of a function.
        *** can also be an expression which evaluates to a function

deftype define a data type (like a struct in c)

msg     send a message for other sprites to execute.
        arguments can be read by other sprites.

pause   force the code to pause. Basically a builtin breakpoint

charat  get string's nth letter
cont?   string a contains string b?
random  pick random a to b

length  length of str
sin     sine (sin cos and tan take angle in degrees)
cos     cosine
tan     tangent
floor   floor function 
ceil    ceiling function
round   round
sqrt    square root
asin    arcsine
acos    arccosine
atan    arctangent
ln      natural log
log     base 10 log
e^      e^
10^     10^

Syntax examples:

(defun add2 var ((var a)(var b))
  (local var output (+ a b))
  (return output)
)
(msg 'say' (add2 3 4) 2)


(deftype 3dpoint-t (
  (var x)(var y)(var z)
))
(local 3dpoint-t p1)
(set (get p1 x) 3)


(local var x)
(local var y)
(set x  (if 
          (= y 0) 'zero'
          (= y 1) 'one'
          (= y 2) 'two'
          'unsupported number'
        )
)

Macros:
There are a few examples under 'Micron default code'. If you have questions about the macro system, feel free to ask me.