Learning Forum

[fdtsaid]

In chapter 2.1.6 Operator instantiation of Scade Primer, there is a scade program as follows:

 

const max: uint64 = 10;

node sigma (e:uint64) returns (sum:uint64)

let

  sum = 0 -> e + pre sum;

tel 

node sample() returns (s:uint64)

let

  s = (restart sigma every (pre s > max))(count());

tel

 

In line 

s = (restart sigma every (pre s > max)) (count());

 

Should pre s > max be true -> (pre s > max)? Because "the reset condition of restart-every cannot be delayed". 

[Benjamin Descorps]

Hello,

Indeed, use of the pre operator is incorrect, missing an init clause.

You can replace :

s = (restart sigma every (pre s >= max))(count ());

by, either:

s = (restart sigma every (fby(s;1;0) >= max))(count ());

or

s = (restart sigma every ((0-> pre s) >= max))(count ());

The error will be fixed in the next SCADE version.

Benjamin