String class

[Clayton]

got bored, so I made a string class, heres the source:

Turing:

class String     import Str     export insert, content, remove, strip, size, make_upper, make_lower, gets, make_original, as_lower, as_upper, as_stripped, originally     var value : string := ""     var original : string := ""     fcn content : string         result value     end content     procedure insert (letter : string (1), position : int)         var oldword := value         value := oldword (1 .. position - 1) + letter + oldword (position .. *)     end insert     procedure remove (position : int)         if original = "" then             original := value         end if         var oldword := value         if position = length (value) then             value := oldword (1 .. * -1)         elsif position = 1 then             value := oldword (2 .. *)         else             value := oldword (1 .. position - 1) + oldword (position + 1 .. *)         end if     end remove     %removes all whitespace from a word     fcn as_stripped : string         if original = "" then             original := value         end if         var oldword := value         var newword := ""         if oldword ~= "" then             for i : 1 .. length (oldword)                 if oldword (i) ~= " " then                     newword += oldword (i)                 end if             end for         end if         result newword     end as_stripped     procedure strip         value := as_stripped     end strip     fcn size : int         result length (value)     end size     fcn as_upper : string         result Str.Upper (value)     end as_upper     procedure make_upper         if original = "" then             original := value         end if         value := Str.Upper (value)     end make_upper     fcn as_lower : string         result Str.Lower (value)     end as_lower     procedure make_lower         if original = "" then             original := value         end if         value := Str.Lower (value)     end make_lower     fcn is_empty : boolean         if value = "" then             result true         else             result false         end if     end is_empty     fcn originally : string         result original     end originally     procedure make_original         value := originally     end make_original     procedure gets         get value : *     end gets end String var my_string : ^String new String, my_string put "Please enter anything " .. my_string -> gets put "All lowercase" put my_string -> as_lower put "All uppercase" put my_string -> as_upper put "Stripped of whitespace" put my_string -> as_stripped put "String size" put my_string -> size put "Inserted \'a\' at position 1" my_string -> insert ("a", 1) put my_string -> content put "Removing \'a\' at position 1" my_string -> remove (1) put my_string -> content put "Original" put my_string -> originally

its really quite readable (it almost reads like english ) so you can probably tell what most of these do. please post suggestions, improvements, constructive critisism etc.

[Hackmaster]

Good Stuff, Freakman...but...

can't you do most of this stuff without this class? you can find the length of a word anyways, and I believe that you can to stuff like toupper and tolower work to0 (but that just might be me thinking in C). but the strip function is cool, and repalcing single letters and such.... that's getting pretty sweet. Hey, you are on your way to making FreeWord!

keep it up!

[Clayton]

sure you can do those things without the class, but the whole point is to make the string an object. As an object, there is so much more freedom and flexibility.

[ericfourfour]

If you want to make something very helpful, not that this isn't helpful, make a BigString class. It would remove the limit from the size of strings.

[[Gandalf]]

Good idea, ericfourfour.

Freakman, not bad, though next time I suggest you do something like learning a new language in your bored time.

Also, the benefits of a String class are greatly diminished in Turing thanks to it's largely awkward OOP syntax.

[Clayton]

Yes I know, but seeing as we're going to be forced of another year of Turing (doing OOP woohoo!), I figured I might as well try and do something to prepare for it....

I guess I could do something like make a module out of it (ie, like they do with most of the other modules, take a class and manipulate it with a module), but then things could get confusing...

[wtd]

You may wish to have separate get and get_line methods.

Also, may I suggest throwing in something a bit functional and having filtering methods which can taken a predicate function as an argument?

[Clayton]

and what might these certain filtering methods do? things like searching through a string for whatever, or something less obvious that I'm missing?

EDIT: I'm working on it right now, and now I really, really appreciate dynamic typing, forcing someone to pass a function with the correct parameters is annoying...

[wtd]

Imagine you wanted to remove all punctuation from a string. So you write a method to do that.

Now you want a method that removes all whitespace. So you write a method to do that.

Except that those methods would be identical, save for one thing... the check to see if a character should be removed. So that can be factored out into separate functions, and those functions passed to a single, generic method.

[Clayton]

not quite sure what you want me to do here. You're saying I should have a generic method that does all of the work, with other functions to be passed to it to specify exaclty what is needed?

[rdrake]

Freakman wrote:

and what might these certain filtering methods do? things like searching through a string for whatever, or something less obvious that I'm missing?

EDIT: I'm working on it right now, and now I really, really appreciate dynamic typing, forcing someone to pass a function with the correct parameters is annoying...

As wtd said below me, there can be slight differences between methods. This in Ruby is usually represented by adding either "!" or "?". For example "chomp" and "chomp!". There are only slight differences between them (one modifies the original value, one does not... but both return the modified value regardless), but they are still slightly different.

[wtd]

Yes. All of the code that handles iterating through the string, and creating a new string... it's the same for both methods. The only thing that changes is how you check each character. So that gets factored out into separate functions.

[Clayton]

What exactly do you mean by "How you check each character"? Does that mean I should have a function that tells the generic function what to remove from a string? If so, would this function be passed to the function from outside of the class, or internally?

[wtd]

Well, to check for punctuation:

code:

function is_punctuation (ch : string) : boolean    result (ch = "." or ch = "," or ch = "!" or ch = "?" or ch = ";") end is_punctuation

[Clayton]

okay, I see where you're going now, so just have said generic method take in that function to check for punctuation, if its punctuation remove it? Or am I still missing something?