[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

*From*: Saswata Paul <paulsaswata1@xxxxxxxxx>*Date*: Sun, 30 Jun 2019 18:29:51 -0400*References*: <ded66eba-ffa2-4ba0-9146-06d1e4f00210@googlegroups.com> <CAJ-b8syp5mDQnBcrgm9yx=WRiWFxxzH2zMuyt6PgUXAS8xWVcQ@mail.gmail.com>

In the example, p and q are symbols which have been used to define the infix operator |. However, they have not been declared or defined before use. Whereas, M, N, x, and y have been defined/declared before using them. My question is, why do M, N, x, and y require a declaration while p and q don't? Aren't they all symbols?

On Sun, Jun 30, 2019 at 3:22 AM Hillel Wayne <hwayne@xxxxxxxxx> wrote:

--Are you talking about this line?p | q == \E d \in 1..q : q = p * d

That's defining the infix operator |, so p and q are the parameters.On Sun, Jun 30, 2019, 12:31 AM Saswata Paul <paulsaswata1@xxxxxxxxx> wrote:In page 11 of the TLA+ hyperbook, it is clearly stated that "Every symbol that appears in the module must either be a primitive TLA+ operator or else defined or declared before its first use.". However, in the example given in the site https://tla.msr-inria.inria.fr/tlaps/content/Documentation/Tutorial/The_example.html, the symbols p and q have not been declared or defined before use. So can someone clarify how we can understand which symbols need to be declared and which do not?--PS: The example code from the site:-------------------- MODULE Euclid -------------------- EXTENDS Integers p | q == \E d \in 1..q : q = p * d Divisors(q) == {d \in 1..q : d | q} Maximum(S) == CHOOSE x \in S : \A y \in S : x >= y GCD(p,q) == Maximum(Divisors(p) \cap Divisors(q)) Number == Nat \ {0} CONSTANTS M, N VARIABLES x, y Init == (x = M) /\ (y = N) Next == \/ /\ x < y /\ y' = y - x /\ x' = x \/ /\ y < x /\ x' = x-y /\ y' = y Spec == Init /\ [][Next]_<<x,y>> ResultCorrect == (x = y) => x = GCD(M, N) THEOREM Correctness == Spec => []ResultCorrect=======================================================

You received this message because you are subscribed to the Google Groups "tlaplus" group.

To unsubscribe from this group and stop receiving emails from it, send an email to tlaplus+unsubscribe@xxxxxxxxxxxxxxxx.

To post to this group, send email to tlaplus@xxxxxxxxxxxxxxxx.

Visit this group at https://groups.google.com/group/tlaplus.

To view this discussion on the web visit https://groups.google.com/d/msgid/tlaplus/ded66eba-ffa2-4ba0-9146-06d1e4f00210%40googlegroups.com.

For more options, visit https://groups.google.com/d/optout.

You received this message because you are subscribed to a topic in the Google Groups "tlaplus" group.

To unsubscribe from this topic, visit https://groups.google.com/d/topic/tlaplus/jXBjiUjfXqY/unsubscribe.

To unsubscribe from this group and all its topics, send an email to tlaplus+unsubscribe@xxxxxxxxxxxxxxxx.

To post to this group, send email to tlaplus@xxxxxxxxxxxxxxxx.

Visit this group at https://groups.google.com/group/tlaplus.

To view this discussion on the web visit https://groups.google.com/d/msgid/tlaplus/CAJ-b8syp5mDQnBcrgm9yx%3DWRiWFxxzH2zMuyt6PgUXAS8xWVcQ%40mail.gmail.com.

For more options, visit https://groups.google.com/d/optout.

You received this message because you are subscribed to the Google Groups "tlaplus" group.

To unsubscribe from this group and stop receiving emails from it, send an email to tlaplus+unsubscribe@xxxxxxxxxxxxxxxx.

To post to this group, send email to tlaplus@xxxxxxxxxxxxxxxx.

Visit this group at https://groups.google.com/group/tlaplus.

To view this discussion on the web visit https://groups.google.com/d/msgid/tlaplus/CAHeFUE_ygwU5LBdOARdiATxrDVJVv0WPW7ug5FW3twcrPA9w1w%40mail.gmail.com.

For more options, visit https://groups.google.com/d/optout.

**Follow-Ups**:**Re: [tlaplus] Which symbols need to be defined? (new to TLA+)***From:*Stephan Merz

**References**:**[tlaplus] Which symbols need to be defined? (new to TLA+)***From:*Saswata Paul

**Re: [tlaplus] Which symbols need to be defined? (new to TLA+)***From:*Hillel Wayne

- Prev by Date:
**Re: [tlaplus] Which symbols need to be defined? (new to TLA+)** - Next by Date:
**Re: [tlaplus] Finite State Machine Visualization** - Previous by thread:
**Re: [tlaplus] Which symbols need to be defined? (new to TLA+)** - Next by thread:
**Re: [tlaplus] Which symbols need to be defined? (new to TLA+)** - Index(es):