Re: very specific question on Ada syntax

[Mario Amado Alves <maa@di.fct.unl.pt>]

> > > Character'('a')
> >
> > This is the killer one.
> 
> Yes, this is well known, and as Tuck says, all production
> quality Ada lexers have known about this for two decades,

Good. I suspected that, but only come into contact with Ada two years ago.

> and handle it with no problem (apostrophe after identifier
> is always a tic). Any lexer not able to do such computations
> will have trouble. Note that if you are using a tool like
> flex, there is absolutely no problem in dealing with this.

I write my lexers "by hand" (I dont understand flex), but without problem
anyway. I already posted the relevant excerpt. Here it is again:

  63   when ''' =>
  64     if Previous_Kind = Identifier
  65     or (Previous_Kind = Delimiter and To_String(Previous_Form)=")")
  66     or Previous_Kind = Reserved_Word_All
  67     then
  68       Send(Delimiter, C);
  69     else
  70       State := Character_Literal_1;
  71     end if;

According to Dewar and Taft (this thread) I should add String_Literal (Taft
only) and Character_Literal to the list of apostrophe-enabling previous
tokens (lines 64-66). But those are syntax errors, no?

I tried

  "123"'Length

on GNAT. It says "binary operator expected" on the apostrophe (error).

Thanks.

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