A simple single line, triple-quoted comment is giving syntax error. Why?

[Thomas 'PointedEars' Lahn]

Ian Kelly wrote:

> […] Thomas 'PointedEars' Lahn […] wrote:
>> Ian Kelly wrote:
>>> What the grammar that you quoted from shows is that STRING+ is an
>>> expression. The individual STRINGs of a STRING+ are not expressions,
>>> except to the extent that they can be parsed in isolation as a
>>> STRING+.
>> How did you get that idea?  STRING+ means one or more consecutive STRING
>> tokens (ignoring whitespace in-between), which means one or more
>> consecutive string literals.  A (single) string literal definitely is an 
>> expression as it can be produced with the “expr” goal symbol of the 
>> Python grammar (given there in a flavor of EBNF).
> 
> Yes, that's what I was referring to in my parenthetical "except..." above.

Your “except” is contradictory to the rest of what you said, at best.

> What I mean is that if you construct a parse tree of "foo" "bar" using
> that grammar, it looks like this:
> 
>      expr
>        |
>     STRING+
>      /   \
> STRING  STRING
> […]
> 
> There is only one expr node, and it contains both STRING tokens.

Prove it.

But be warned: Neither would prove that a string literal is not an 
expression.  Because you did not consider the most simple variant of an AST 
(or subtree) according to this grammar:

    expr
     |
   STRING

Again, “STRING+” does _not_ mean “STRING STRING STRING*”; it means “STRING 
STRING*”.  The second and following STRINGs are *optional*.

>> […] in the used flavour of EBNF the unquoted “+” following a goal symbol
>> clearly means the occurrence of *at least one* of the immediately
>> preceding symbol, meaning either one *or more than one*.
> 
> It means one or more *tokens*, not one or more literals.

Utter nonsense.  Have you ever written a parser?  (I have.)  A literal *is* 
a token.  Whether two consecutive tokens end up as the same *node* in an AST 
is a *different* issue (that, again, was _not_ debated).
 
 
-- 
PointedEars

Twitter: @PointedEars2
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