|Precise definition of "syntax diagram" firstname.lastname@example.org (1990-10-18)|
|From:||email@example.com (Hank Dietz)|
|Organization:||Purdue University Engineering Computer Network|
|References:||<9010091533.AA02386@apple.com> <9010101445.AA06181@dynamo.ecn.purdue.edu> <1990Oct16.firstname.lastname@example.org>|
|Date:||Thu, 18 Oct 90 01:39:40 -0500|
In article <1990Oct16.email@example.com> firstname.lastname@example.org (Lindsay Groves) writes:
>In article <9010101445.AA06181@dynamo.ecn.purdue.edu>,
>email@example.com (Hank Dietz) writes:
>|> Pascal is generally defined using a set of syntax diagrams which, by
>|> definition, means the language can be recognized using LL(1).
>You must be using a strange definition a syntax diagrams if they can
>only describe languages that have LL(1) grammars.
The rule I have heard is that a syntax diagram is literally a flowchart
for an LL(1) parser where the branching decisions are obvious, hence
the branch decision nodes are omitted. This was certainly true of all
syntax diagrams I saw earlier, but I have more recently seen "syntax
diagrams" which are no more constrained than arbitrary CFGs + looping,
and differ from them only in having arrows between symbols.
E.g., is the following a legal syntax diagram for S -> S a, S -> b?
I believe it isn't. Right or wrong? References, anyone?
PS: The unconstrained form looks more like a RTN to me....
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