Summary (Abstract Syntax)

P in Program	L in Variable
D in Declaration	N in Numeral
T in Type-structure	X in Identifier-expr
C in Command	I in Identifier
E in Expression

P ::= D in C
D ::= D$$₁,D$$₂ | D$$₁;D$$₂ | fun I=E | const I=N
        | proc I=C | var I:T | class I=T
        | module I={D} | import X
T ::= newint | record D end | X
C ::= L:=E | C$$₁;C$$₂ | if E then C$$₁ else C$$₂ fi
        | while E do C od | skip | call X
E ::= N | @L | E$$₁+E$$₂ | E$$₁=E$$₂ | not E | X
L ::= X
N ::= $n$ | X
X ::= I | X.I