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Arithmetic evaluation: Difference between revisions
→{{header|Elena}}
Line 1,235:
].
</lang>
=== ELENA VM script ===
<lang elena>numeric ::= "(" sub_expr;
numeric ::= $numeric;
factor ::= $numeric factor_r;
factor ::= "(" sub_expr;
sum ::= "+" factor ;
difference ::= "-" factor ;
multiply ::= "*" numeric;
divide ::= "/" numeric;
factor_r ::= multiply factor_r;
factor_r ::= divide factor_r;
factor_r ::= $eps;
expr_r ::= sum expr_r;
expr_r ::= difference expr_r;
expr_r ::= $eps;
neg_r ::= factor_r expr_r;
sub_expr ::= expression sub_expr_r;
sub_expr_r ::= ")" factor_r;
neg_expression ::= $numeric neg_r;
expression ::= factor expr_r;
expression ::= "-" neg_expression;
print ::= "?" expression;
start ::= print;
print => &nil 'program'output $body ^write;
multiply => $body ^multiply;
divide => $body ^divide;
sum => $body ^add;
difference => $body ^subtract;
neg_expression => 0 $token ^subtract;</lang>
=={{header|Factor}}==
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