Re: Incorrect definition of expressions in grammar

ken Koch wrote:

> Looking through the grammar spec and expressions definitions i noticed
> a naming inconsistency that causes some problems in the grammar.
> 
> The problem is around the `expression` for instance:
> 
> primary-expression:
>     variable-name
>     qualified-name
>     literal
>     const-expression
>     intrinsic
>     anonymous-function-creation-expression
>     (  expression  )
>     $this
> 
> The definition of the  `expression` production is given later under
> "script inclusion operators":
> 
> expression:
>     yield-expression
>     include-expression
>     include-once-expression
>     require-expression
>     require-once-expression
> 
> My suggestion is that the `expression` symbol under "script inclusion
> operators" be renamed to `script-inclusion-expression` and all
> references to `expression` in the context of primary expressions be
> renamed to `primary-expression`.
> 
> Not sure if i am misinterpreting it there but it seems to make much
> more sense to me that way. I wanted to get the lists opinion before
> putting it together in a PR.

Replacing "expression" in "primary-expression" with "primary-expression"
would be wrong -- at least it would make PHP pretty useless.

As it is now, the grammar seems to be correct, but I agree that it it
somewhat confusing to define

| yield-expression:
|   logical-inc-OR-expression-2
|   yield  array-element-initializer

especially considering the specified semantics:

| Any function containing a yield-expression is a generator function.

That makes nearly every function a generator function.

It might be better to define

  expression:
    logical-inc-OR-expression-2
    yield-expression
    include-expression
    include-once-expression
    require-expression
    require-once-expression

  yield-expression:
    yield  array-element-initializer

BTW: the following[1]

| Except for the difference in precedence, operator and has exactly the
                                                    ^^^
| same semantics as operator ||.

should be

  Except for the difference in precedence, operator or has exactly the
                                                    ^^
  same semantics as operator ||.

[1]
<https://github.com/php/php-langspec/blob/master/spec/10-expressions.md#user-content-logical-inclusive-or-operator-form-2>

-- 
Christoph M. Becker