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Expression Abstractions

Expression abstractions = functions.

P in Program	L in Location
D in Declaration	N in Numeral
C in Command	I in Identifier
E in Expression

P ::= D in C
D ::= fun I=E | D₁,D₂ | D₁;D₂
C ::= L:=E | C₁;C₂ | if E then C₁ else C₂ fi
        | while E do C od | skip
E ::= N | @L | E₁+E₂ | E₁=E₂ | not E | I
L ::= loc_i, i>0
N ::= n, n in Int

• New domains Identifier and Declaration.
• Definition: fun I=E.
• Invocation: I.