Re: FAQ and string functions

[Oleg Goodyckov <og@videoproject.kiev.ua>]

On Sat, Aug 03, 2002 at 01:29:23AM +0200, Dmitry A.Kazakov wrote:
> 
> My implementation (for parsing unit expressions) is about 0.5K lines long. 
> Is that much?

500 bytes?

> > In couple of next steps of program error will be recognized and exception
> > rised. No problem.
> 
> Usually at that point, there is nothing to say about the error and its 
> location. Like an old Borland Pascal compiler, which promptly reported 
> "Line X, error in expression" for almost any error.

It is not right (as for me) to process EVERY error in input data. As for
me it is more effectively to process only correct data (which are reliably
recognized) and any other simply to drop nuffig.

> > Difference is like difference between RANDOM and SEQUENTIAL acceses to
> > data.
> 
> This is a good point. There is also a technical term for that. There are 
> global and local methods of processing texts, images etc. Global methods 
> (split is one) are working good for only small anount of data.

What here global and local methodes are for? For making conclusion "global
methods are working good almost never", so they are nuffig need not?
Config files of applications - are they small amount of data? Yes. But it
exists in every application. And to parse it splitting of string to
several independent fields is much more effective and convinient way than
make some sequential syntactical analyzing.

> > In many cases it is not necessary to analyze all of string - enought to
> > know count of tokens or several from them on several well known positions.
> 
> Well, pattern matching does the work. Others have pointed that. Note also, 

Of cause, touch left ear by right hand is possible. Somthing stupied, but
nothing impossible. Entirely acceptable in many cases.

> that as the complexity of syntax increases it becomes almost impossible at 
> some point to write a correct pattern and prove that it is correct.

Which nuffig "complexity of syntax"? Syntax is - no more simplest: fields
with separators (of one type) between of them. Take record, split it by
separators and enjoy.
No! Give me a syntax...


> [ example snipped ]
> 
> First, the example is not realistic but illustrative. A real-life example 
> would take into accout different spellings, typo errors, proper nouns, 
> multi-word tokens etc. It would probably work with a data base, it would 
> surely avoid unbounded strings (heap allocation) and so on and so far. I 
> doubt that a Perl implementation of all that would be simplier or shorter 
> than in Ada.

Really? Empty words. Try and show me. In skipped example I've seen one
attempt. Show me another - better.
Task solved in skipped example has name - building hystorgram of words
implementation. Why you name this task not realistic?

> Second, the 80% of the example code is dealing with s/w components like 
> containers etc. This has nothing to do with text processing. What is really 
> dedicated to parsing is quite short and transparent.

So, if that 80% of code throw out, then program will work? Or they are
necessary though?

> You might argue that Ada should have standard components standard (:-)), it 
> is questionable, but as you see (Ada Standard Component Library) there is a 
> work going in the direction of having that components, though maybe not as 
> a part of the standard.

So, my words have sence? Why then you argue?