Grammar in choice-domain documentation is incorrect

[Langston Barrett]

The grammar for choice-domain looks like this:

<relation-declaration>      ::= ".decl" <relation-name> "(" <attributes> ")" <choice-domain>
<choice-domain>            ::= "" | "choice-domain" (<constraint>)+
<constraint>               ::= <attribute> | "(" <attributes> ")"

The <attributes> non-terminal is not defined, but if we assume from context that it's what fits between the parentheses in a .decl, it should have the form <variable>: <type>, .... But that isn't true:

.decl foo(x: number, y: number) choice-domain (x: number, y: number)

$ souffle --version
Souffle: 2.0.2-987-gbcb2a08e5(32bit Domains)
Copyright (c) 2016-19 The Souffle Developers.
Copyright (c) 2013-16 Oracle and/or its affiliates.

$ souffle test.dl 
Error: syntax error, unexpected :, expecting ) or "," in file test.dl at line 1
.decl foo(x: number, y: number) choice-domain (x: number, y: number)
------------------------------------------------^--------------------
1 errors generated, evaluation aborted

Instead, two different non-terminals are needed, one for <relation-declaration> and one for <constraint>, where the latter just includes variable names but the former includes their types.

[Bernhard Scholz]

Thanks for noting this. Can you rewrite the documentation accordingly? Many thanks.