A Abstract syntax
Responsible: Karsten Stahl, Martin Steffen, and all others
The following extended BNF-notation specifies the abstract
syntax as common intermediate data represenation for the project. Modulo
some naming conventions (capitalization), the Java-implementation is
straightforward. Each non-terminal is represented as a separate class.
Alternatives, specified by |, are subclasses of the abstract
class, to which they build the alternative. The entries of the middle
collum constitute the fields of the classes. The constructors of the
classes are conventionally fixed by the fields of the class (up to the
order of the arguments.1 The lists of the EBNF are implemented as
java.lang.LinkedList. Graphical position information, relevant
only for the editor and the layout group, is omitted in the EBNF.
SFC ::= istep : step
steps : step list
transs : transition list
actions : action list
declist : declaration list
step ::= name : string
actions : stepaction list
stepaction ::= qualifier : action_qualifier
a_name : string
action ::= a_name : string
sap : stmt list (* simple assignment program *)
stmt ::= skip
| assign
assign ::= var : variable
val : expr
variable ::= name : string
type : type
action_qualifier ::= Nqual (* may be extended *)
transition ::= source : step list
guard : expr
target : step list
declaration ::= var : variable
type : type
val : constval
expr ::= b_expr
| u_expr
| constval
| variable
b_expr ::= left_expr : expr
right_expr : expr
op : operand
type : type
u_expr ::= sub_expr : expr
op : operand
type : type
operand ::= PLUS | MINUS | TIMES | DIV (* Operand als *)
| AND | OR | NEG (* Konstanten in expr *)
| LESS | GREATER | LEQ | GEQ | EQ | NEQ
constval ::= ...| -2 | -1 | 0 | 1 | ... | true | false
type ::= inttype
| booltype
last generated June 14, 2002 (©Public License)