So i'm trying to make my own Programming Language but don't really know how. I have looked it up but people say try using Python to make it, well i mean how do you make your own language like to use python you would have to Install it, Well to use my language you would have to install it aswell. How would someone make it also add Syntax Highlighting. I have tried making it in Lua and i'm not to Successful
I'm not able to make everything like that, and i also wanna have my own custom Syntax Highlighting but choose the colors like this
Syntax = {
log/Log/LOG = Blue; -- Print Function
bringback = Red; -- return function
}
function ByteText(...)
string.Byte(...)
end
function CustomFunctionsName(data)
Do(Data)
end
So i'm kinda successfull in this but i don't want it running of Lua i don't mind using a Lua api or c# or python api but i just want to learn how to make it customly like how did python and LOLCODE make their own languages? I wan't to make it like that LOLCODE's functions are so random and i wanna make it Customly and my own way just like them, If someone can Explain that would be amazing <3
You don't say why you'd want to write your own language when there are plenty available, but to answer your question....
Start by searching "language parsers" in your favorite search engine.
Learn about language parsing itself. If you're still interested after that (and it isn't an easy topic if you intend to write something from scratch) you should be able to figure out where to go next.
P.S.
Your first worry is only about what your language will accomplish and what grammar it will support. Stuff like syntax highlighting isn't something to worry about until after your language is written and can compile itself.
Related
Im new to uipath and coding in general. I know most of the basics from what was taught but they didnt go through how to form "condition" statements in the "if" activity. or basically any form of conditions. Where can i go about to learning them? is it a specific language?
kinda like: not Months.Contains(ExpenseMonth)
i wouldnt be able to come up with that because i dont know what is acceptable/readable to uipath studio
also regarding those calculations. where can i find more information on those? to learn more about
kinda like: (int32.Parse(row("Value").ToString) * 100 / monthlyTotal).ToString
they didnt really give me details on how to form that
so essentially, if i wasnt spoon fed with those statements, i would be stuck
It depends on which activity you are using. Usually it's VB.net. Find more about that programming language here.
And yes you will need to get the basics of that language on your own. UiPath isn't really helping you find the correct condition. It is more a tool that can use VB.net.
And soon you can switch to C# completely. But that is not yet ready and still experimental. Also, I would recommend you to stay with VB.net as it is way easier to learn as a first language. Currently, you can only use C# and Invoke Code activity.
To your first example from above:
not Months.Contains(ExpenseMonth)
That depends on your variable type. That looks like a DateTime or a String type and so you are able to use predefined functions that come with it. You can show them but simply clicking CTRL + SPACE after the dot.
And your second one:
(int32.Parse(row("Value").ToString) * 100 / monthlyTotal).ToString
I would always recommend you to use CInt instead of int32.parse. Look here. And it is often not needed to convert the row value into a String. As it is usually already in that type by default.
But again. You will need to learn the basics of VB.net before you are able to write a good business logic in UiPath that makes sense and is best practice.
I've just started learning about metaprogramming in Ruby, and found myself wondering if it was possible to view (in someway) the code that had been generated. I want to, as a coding exercise, write a short method that will generate a Ruby file containing either a few method definitions or, ideally, an entire class or module definition.
I was thinking that perhaps just building up a string representation of the file and then merely writing it out might be a way to accomplish that, but that way doesn't really necessitate the use of metaprogramming, and since my goal is a metaprogramming exercise, I would like to figure out a way to incorporate it into that process or else do it another way.
I guess, if I was to take the string-building approach, I would like to start with something like
klass_string = "class GeneratedClass\n\t<BODY>\nend"
and then somehow save the output of something like this
define_method( :initialize ) do
instance_variable_set("#var", "some_value")
end
in a string that could replace '' in klass_string and then written out to a file. I know I could just put the above code snippet directly into the string, and it would workout fine, but I would like to have the output in a more standard format, as if it'd been written by hand and not generated:
class GeneratedClass
def initialize
#var = 'some_value'
end
end
Could someone point me in the right direction?
I agree with your comment that this question isn't really about metaprogramming so much as dynamic code generation / execution and introspection. Those are interesting topics, but not really metaprogramming. In particular your question about outputting ruby code to strings is about introspection, where as your string injection question is about dynamic code (just to try give you the words to google about what you're interested in).
Since your question is general and really around introspection and dynamic code, I'm going to reference you to some canonical and useful projects that can help you learn more..
ParseTree & Ruby Parser and Sourcify
Ruby Parser is a pure ruby implementation of ParseTree, so I'd recommend starting there to learn how to examine and "stringify" Ruby code. Play around with all of those, and in particular learn how they examine code in Ruby to generate their results. You'll learn a ton about how things work under the hood. Eric Hodel among others is real smart about this stuff.. Be warned though, this is really advanced stuff, but if that's where you want to build expertise, hopefully those references will help!
I am building a app like a compiler with my own script language. The user will enter the code and the output will be another app.
So I need tell to user if some line is wrong and why it is.
But I don't know how to start.
I thought this:
All lines will start with a keyword, except for those who start with an variable. So different that are wrong.
So, I can calculate the next valid entries and check them.
Also, I thought that I can check each line, but it's complex because I can have this
var varName { /* ... */ };
Or
var varName {
/* ... */
};
Or Even
var varName
{
/* ... */
};
So why not remove the break-lines and check? Because I will lose the line number, which in this case is the most important.
Maybe I'm going to create a map between the code with and without break-line.
But first I want to hear you, if you already has this experience or you have any idea.
Thanks
There are formal languages to describe syntax and semantics of the language and there are tools that will generate parsers out of these descriptions. I suggest reading on flex and bison for starters.
It'll be fairly complicated to write your own language. But totally doable.
To able to recognize if a line is wrong, in the syntactical sense, you'd need to build a parser.
The parser checks the context-free grammar for a correct derivation of a structure from its tokens.
First you need to tokenize the file, then reconstruct it into a parse tree (to check syntax).
I took a class in this, CS 241. There's a very nice set of course notes which this is all explained in detail.
https://github.com/christhomson/lecture-notes/blob/master/cs241.pdf
You should check tools like: lex, bison and yacc.
lex is lexical analyser generator. It generates a code, which could be used for breaking the script to tokens (like numbers, keywords and so on...).
bison and yacc are both parser generators. Both can be used for generating code for parsing your language (combining tokens to statements).
Just google tutorials for those tools.
I have been searching for a FAQ to tell me how to open a Excel Workbook/Worksheet and also how to Save the File once I have finished.
I notice that in most FAQ and all the books I have purchased on F# one is show how to create a new Workbook/Worksheet but is never shown how to either open or Save it.
Being a newbie to F# I would very much appreciate it if anyone could kindly provide me with either an answer or perhaps a few pointers?
Update
As for why F# and not C# or VB?
I am pleased to say that inspite of being a newbie (with the exception of Forth, VBA & Excel 2003, 2007 & 2010 and Visual Basic) I can do this in both VB, VBA & C# and since I've been retired on medical grounds, with plenty of time unfortunately on my hands, I like to continually set myself challenges to keep my little grey cells active and being a sucker for trying new languages....well!
F# is now an intergral part of Visual Studio 2010 so I thought - why not. Consider this - if we are not willing to use or at least try a new languages - I would always be wonder if I might have prefer it to VBA, VB, C# ..... and if you look at it from another point of view, if no one is going to use it - why create it in the first place? I suppose you can say if cave men hadn't experimented and made fire by rubbing two sticks together - where would we be now and would matches have been invented?
Although an complete answer would be good, I prefer a few pointers, to keep my challenge going.
And lastly but not least - thank you for taking the trouble to respond!
I don't think their is a specific F# library for Office, so you will just use the exact same .NET library that you use in VB.NET/C#. F# is a .NET language, so anything that can be done in C# can be done in F# (but you probably already knew that :) ). The API call will be exactly the same, it just that they will be done using the F# syntax instead of the VB/C# one. So for example something that look like this
public void SaveMyWorkbook() {
string filePath = #"C:\failworkbooks\catfail.xlsx";
workbook.Save(filepath);
}
Will be expressed in F# as
let filePath = "C:\\failworkbooks\\catfail.xlsx";
let saveWorkbook() = workbook.Save(filePath) |> ignore //if the Save method return something
Now, what you will soon realize is that the API isn't exactly designed to be easily used from a functional language. It can be done, but this task in particuliar is much more tailored to C#/VB.NET.
If you really want to enjoy F#, I suggest you use in area where its strength really show. My personal experience is that functional language are awesome when a lot of math is involved. It is also marvellous if you want to easily introduce parallelism in your application (since F# code is usually side effect free). So anything that require data crunching on a lot of data is perfect for it. But for task that consist mainly of putting together a bunch of API call to an external library, F# is kind of meh. You could say that F# is kind of like a graphic card programming language, while C# a general purpose CPU programming language. A lot of thing run better with C#, but the stuff that run better on F# run really better on it.
But if you really want to go that route, my suggestion is to try to use the Office API as you already know it, but with a F# syntax. If at some point you really have no idea how to do a specific task, ask a question about it on stackoverflow with your code and exactly want you want to do. Those question get answered ridiculously fast compared to broad all-encompassing question, so you won't wait long. (Programmer seem to love precise question with a specific answer ^^)
I hope that it helped a little.
I found this http://iouri-khramtsov.blogspot.co.uk/2011/12/automating-excel-with-f.html helpful advice. Briefly, you'd use something like this:
#r "Microsoft.Office.Interop.Excel" // Assuming it's a script
let excel = ApplicationClass(Visible = true)
let openFileName = #"C:\MyDir\MyFilenameToOpen.xls"
excel.Workbooks.Open(openFileName)
// Do stuff
let savedFileName = #"C:\MyDir\MyFilename.xls"
workbook.SaveAs(savedFileName)
Using F# with Excel seems like a natural fit.
Getting to a result in Excel requires the use of several immutable values, each driven by formulas. Excel has a brilliant user interface, a lovely model of the world - I love rows, columns and cells - but to automate or customise things requires macros. Why learn this when you can use F#? Formulas and immutable values are fundamental to its design.
Ideally you'd write formulas yourself as a User Defined Function (UDFs) also in F# - see http://excel-dna.net/ . Then, perhaps, you'd want to do something interesting with objects/types - Look for "github com mndrake ExcelObjectHandler" (I don't have enough reputation to post a 3rd link).
Jack
In response to a previous question on how to achieve a certain effect with Swing, I was directed to JDesktopPane and JInternalFrame. Unfortunately, scala.swing doesn't seem to have any wrapper for either class, so I'm left with extending it.
What do I have to know and do to make minimally usable wrappers for these classes, to be used with and by scala.swing, and what would be the additional steps to make most of them?
Edit:
As suggested by someone, let me explain the effect I intend to achieve. My program controls (personal) lottery bets. So I have a number of different tickets, each of which can have a number of different bets, and varying validities.
The idea is displaying each of these tickets in a separate "space", and the JInternalFrames seems to be just what I want, and letting people create new tickets, load them from files, save them to files, and generally checking or editing the information in each.
Besides that, there needs to be a space to display the lottery results, and I intend to evolve the program to be able to control collective bets -- who contributed with how much, and how any winning should be split. I haven't considered the interface for that yet.
Please note that:
I can't "just use" the Java classes, and still take full advantage of Scala swing features. The answers in the previous question already tell me how to do what I want with the Java classes, and that is not what I'm asking here.
Reading the source code of existing scala.swing classes to learn how to do it is the work I'm trying to avoid with this question.
You might consider Scala's "implicit conversions" mechanism. You could do something like this:
implicit def enrichJInternalFrame(ji : JInternalFrame) =
new RichJInternalFrame(ji)
You now define a class RichJInternalFrame() which takes a JInternalFrame, and has whatever methods you'd like to extend JInternalFrame with, eg:
class RichJInternalFrame(wrapped : JInternalFrame) {
def showThis = {
wrapped.show()
}
}
This creates a new method showThis which just calls show on the JInternalFrame. You could now call this method on a JInternalFrame:
val jif = new JInternalFrame()
println(jif.showThis);
Scala will automatically convert jif into a RichJInternalFrame and let you call this method on it.
You can import all java libraries directly into your scala code.
Try the scala tutorial section: "interaction with Java".
Java in scala
You might be be able to use the scala.swing source as reference e.g. http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk/src/swing/scala/swing/Button.scala
What sort of scala features are you trying to use with it? That might help in coming up with with an answer. I.e. - what is it you're trying to do with it, potentially in Java? Then we can try to come up with a nicer way to do it with Scala and/or create a wrapper for the classes which would make what you're trying to do even easier.
In JRuby, you could mix in one (or more) traits into JDesktopPane or JInternalFrame instead of extending them. This way you wouldn't have to wrap the classes but just use the existing objects. As far as I know, this is not possible with Scala traits.
Luckily, there is a solution, almost as flexible as Ruby's: lexically open classes. This blog article gives an excellent introduction, IMHO.