string helpers question

[David Schwartz 415]

I'm using Tokyo 10.2.3 and poking around the string helper functions, and noticed there's a function .Contains( string ) : boolean

 

I want a case-insensitive version. ContainsText(string) doesn't make sense. But then I noticed there's a Lowercase function.

 

But it's Lowercase(string).... 

 

These are all class functions so they don't have an object/record attached. So given

 

var aStr : string;

 

it looks like you can't say: if aStr.Lowercase.Contains( 'xyz' ) then ...

 

You need to say: if ContainsText( aStr, 'xyz' ) to get what you want. So what's the point?

 

Looking at the members of this string record helper, it appears that a ton of members are functions that take an argument that should be the string they're "helping".

 

I'm kind of baffled at the apparent lack of utility of: aStr.Lowercase(aStr) when it's the same as Lowercase(aStr).

 

There's a nice variety of functions there, but since they all take an explicit argument, they appear to be gratuitous since the string in front is ignored.

 

What am I missing?

Edited September 22, 2020 by David Schwartz

[David Heffernan 2308]

DELETED: because it was nonsense

 

 

 

Edited September 22, 2020 by David Heffernan

[Uwe Raabe 1898]

I agree about Contains missing a case-insensitive option. On the other hand, the requested LowerCase functionality is already there under the name ToLower.

 

Alas, there are more functions missing from the string helper where you need to fall back to the global ones.

[Fr0sT.Brutal 897]

43 minutes ago, Uwe Raabe said:

I agree about Contains missing a case-insensitive option. On the other hand, the requested LowerCase functionality is already there under the name ToLower.

In general, AFAIK, comparing lowercased versions <> case-insensitive comparing. It's the case for some languages. Moreover, in theory direct case-insensitive comparation should be faster than creating a new string + comparing because many languages do not have case at all.

[Stefan Glienke 1906]

Fun fact: .net framework also is missing this in its String.Contains but .net core added an overload where you can pass an additional option how to compare.

Let's remember back when TStringHelper was introduced into Delphi... yep that must have been around the time when .net did not have the overload yet (was introduced in core 2.1)

Edited September 22, 2020 by Stefan Glienke

[Anders Melander 1652]

2 hours ago, David Schwartz said:

What am I missing?

The manual apparently

 

1 hour ago, Fr0sT.Brutal said:

In general, AFAIK, comparing lowercased versions <> case-insensitive comparing.

There's a string.ToLowerInvariant for that purpose.

 

1 hour ago, Fr0sT.Brutal said:

many languages do not have case at all.

The ancient Egyptians? I think they just used a larger chisel for emphasis

 

48 minutes ago, Stefan Glienke said:

Let's remember back when TStringHelper was introduced into Delphi... yep that must have been around the time when .net did not have the overload yet

That also makes it easier to write the feature specification: Just copy everything that .NET does.

In some cases they even copied their documentation verbatim but failed to realize that it referenced stuff that they hadn't copied.

 

I think a big problems with the string helpers is that they operate on zero based string indices. As if we didn't have enough opportunity off-by-one errors already.

[Lars Fosdal 1732]

31 minutes ago, Anders Melander said:

The ancient Egyptians? I think they just used a larger chisel for emphasis

ROFL!

[Uwe Raabe 1898]

48 minutes ago, Anders Melander said:

I think a big problems with the string helpers is that they operate on zero based string indices

Actually, I like this and make heavy use of it. 

begin
  if Value.StartsWith(Prefix, IgnoreCase) then
    Result := Value.Substring(Prefix.Length)
  else
    Result := Value;
end;

is just easier to read than

var
  isPrefixed: Boolean;
begin
  if IgnoreCase then
    isPrefixed := StartsText(Prefix, Value)
  else
    isPrefixed := StartsStr(Prefix, Value);
  if isPrefixed then
    Result := Copy(Value, Length(Prefix) + 1, Length(Value))
  else
    Result := Value;
end;

 

[Anders Melander 1652]

2 minutes ago, Uwe Raabe said:

just easier to read

I'm not saying "don't use string helpers". I'm saying that if they had made them 1-based like God intended then there would have been less confusion. Now we have one set of functions that are 1-based and one that is 0-based. How is that improvement?

 

Ironically I had to look at your 1-based example to figure out what you 0-based example did. Here's a 1-based version without the bias:

begin
  Result := Value;
  if Result.StartsWith(Prefix, IgnoreCase) then
    Delete(Result, 1, Prefix.Length);
end;

 

[Rollo62 503]

7 minutes ago, Anders Melander said:

made them 1-based like God intended

The 0 took a long way over centuries.

Maybe HE was not aware of that when HE created the world in 7 days.

[Anders Melander 1652]

I think maybe she used a 3 bit computer and the "7 days" legend is just the result of the actual count overflowing. Anyway. I was referring to an actual entity, not an imaginary one.

[Fr0sT.Brutal 897]

2 hours ago, Anders Melander said:

The ancient Egyptians? I think they just used a larger chisel for emphasis

Contemporary Chinese, Japanese, Arabs, Thais, Koreans, Indians etc are roflin' with you

[Rollo62 503]

3 hours ago, Anders Melander said:

I think maybe she used a 3 bit computer and the "7 days" legend is just the result of the actual count overflowing. Anyway. I was referring to an actual entity, not an imaginary one.

Probably like that, with full control over address and data bus (only with 3 bit data bus).

Simple operation, one switch at a time, switch 1 = 1, switch 2 = 2, switch 3 = 4 (WHAT ??)
While the "0" in those days was considered to be "AI", based on fuzzy quantum states.

 

Until then: This (not further known) person invented the "0", to be used in a computer:

From that day the real 3-Bit computer was born, and could made first calculations:

switch 1,2,3 OFF = 00

switch 1 = 1

switch 2 = 2

switch 3 = 4  (still nobody knew what was going on here, it should be 3,  well who cares)
switch 1,2,3 ON = 007

 

That was the day, HE, SHE or IT was happy, and called it SUM-Day.

(Later the romans made wrong translation, we call it now sunday).

 

 

 

 

 

Edited September 22, 2020 by Rollo62

[Anders Melander 1652]

48 minutes ago, Rollo62 said:

Simple operation, one switch at a time, switch 1 = 1, switch 2 = 2, switch 3 = 4 (WHAT ??)

1 bit, 2 bit, 3 bit, 4

4 bit, 3 bit, 2 bit, 1

You're bit, he's bit, no bit, none

- Eminem

[David Schwartz 415]

My question had more to do with the fact that the string helpers all appear to take an argument that's redundant.

 

that is,

 

(aStr.LowerCase = LowerCase(aStr)  should be true.

 

Here you apparently need to say: aStr.LowerCase(aStr)  which just seems silly. There are a TON of string helper methods that require the parameter you're working with as an explicit argument.

[Attila Kovacs 617]

8 minutes ago, David Schwartz said:

There are a TON of string helper methods that require the parameter you're working with as an explicit argument.

 

Mind the declaration of those helper routines.

The ones needing a parameter are for sure class methods, thus they will as work with aStr.xyz() as with String.xyz(); 

In this case the ToLower is non-class method, LowerCase is.

Now if you wonder why are they called differently, try boolean.ToString(True); and once you found out what is happening try not to scream.

 

[Anders Melander 1652]

11 hours ago, Attila Kovacs said:

try boolean.ToString(True); and once you found out what is happening try not to scream

Yeah, that one is one of the more stupid things I've encountered. But what does it have to do with the naming?