Port-expressions
Recognizers and functions for working with well-formed port
expressions.
Our vl-port-p recognizer doesn't place any restrictions on a
port's expression, except that it should satisfy vl-maybe-expr-p.
However, per Verilog-2005, Section 12.3.2, "the port reference for each
port in the list of ports at the top of each module declaration can be one of
the following:
- A simple identifier or escaped identifier
- A bit-select of a vector declared within the module
- A part-select of a vector declared within the module
- A concatenation of any of the above.
SystemVerilog-2012 presents identical rules in Section 23.2.2.1.
Note that nested concatenations are not permitted under these rules, e.g.,
whereas .a({b,c,d}) is a valid port, .a({b,{c,d}}) is not. Simple
tests suggest that indeed none of Verilog-XL, NCVerilog, or VCS permits any
nested concatenations here; see for instance failtest/port13.v.
We now introduce recognizers for the accepted expressions.
Portexprs. We recognize the set of expressions described above with
vl-portexpr-p. Note that this function only checks the basic shape of
its argument—it doesn't check that the names are unique or valid or that
indices are sensible or anything like that.
Well-formed ports. We extend the idea of portexprs to check whole
ports in vl-port-wellformed-p. This function accepts any interface
ports or blank ports without complaint. However, for any regular ports with
regular expressions, it insists that the expression is a portexpr.
Internalnames. Given a valid portexpr, we can easily collect up the
identifiers that occur within it. The main function to do this for a portexpr
is vl-portexpr->internalnames. This is a bit different than, e.g., just
using vl-expr-names, because it omits any names that occur in index
expressions.
Subtopics
- Vl-atomicportexprlist->internalnames
- (vl-atomicportexprlist->internalnames x) maps vl-atomicportexpr->internalname across a list.
- Vl-port-direction
- Attempt to determine the direction for a port.
- Vl-portlist->internalnames
- (vl-portlist->internalnames x) applies vl-port->internalnames to every member of the list x, and appends together all the resulting lists.
- Vl-portexpr->internalnames
- Collect the names of any internal wires that are connected to a
well-formed port and return them as a list of strings.
- Vl-portdecls-with-dir
- Filter port declarations by direction.
- Vl-plainarglist-blankfree-p
- (vl-plainarglist-blankfree-p x) recognizes lists where every element satisfies vl-plainarg-blankfree-p.
- Vl-namedarglist-blankfree-p
- (vl-namedarglist-blankfree-p x) recognizes lists where every element satisfies vl-namedarg-blankfree-p.
- Vl-modinstlist-blankfree-p
- (vl-modinstlist-blankfree-p x) recognizes lists where every element satisfies vl-modinst-blankfree-p.
- Vl-ports-from-portdecls
- Construct basic ports corresponding to a list of portdecls.
- Vl-portlist-wellformed-p
- Recognizer for port lists whose expressions are well-formed.
- Vl-maybe-portexpr-p
- Recognizes all expressions that can validly occur in a (possibly blank) port.
- Vl-portexpr-p
- Recognizes all expressions that can validly occur in a (non-blank) port.
- Vl-atomicportexpr-p
- Recognize non-concatenations that can occur in port expressions.
- Vl-atomicportexpr->internalname
- Vl-port->internalnames
- Vl-atomicportexprlist-p
- (vl-atomicportexprlist-p x) recognizes lists where every element satisfies vl-atomicportexpr-p.
- Vl-port-wellformed-p
- Recognizer for ports whose expressions are well-formed.
- Vl-plainarg-blankfree-p
- Vl-namedarg-blankfree-p
- Vl-modinst-blankfree-p
- Vl-arguments-blankfree-p
