Support SIZE of direction-annotated channel name

[associate-1]

Difficulty: Easy — Strip trailing ?/! direction suffix when parsing SIZE operand.

Summary

When a channel parameter has a direction annotation (e.g., monitor?), the SIZE operator should work on it by stripping the direction suffix. Currently SIZE monitor? fails to parse.

Occam syntax

PROC foo([]CHAN OF INT monitor?)
  SEQ i = 0 FOR SIZE monitor?
    ...

Proposed Go mapping

func foo(monitor []chan int) {
    for i := 0; i < len(monitor); i++ {
        ...
    }
}

The ? suffix is purely a direction annotation and should be stripped when generating the len() call.

Affected files

• sort_inside_2.occ (line 294)

Work required

1. Parser: When parsing SIZE, handle the case where the operand identifier has a trailing ? or ! direction annotation
2. Codegen: Generate len(name) with the direction suffix stripped

Part of #43.