Monday, September 29, 2008

F# Winform

When you want to make a F# winform application and you don’t want to open an extra console when you start the application.

How can you do this (F# version 1.9.6.2)?

1. Create a F# application:

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[Edit- thanks Brian ]

2. Open the project properties

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3. In the application tab change the output type

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4. Add reference to the System.Windows.Forms

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5. Add your code.

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6. Run your app

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7. Close.

8. Add your own details.

Monday, September 22, 2008

Creating a parser with F#

I want to write my own html-parser. That is one of the reasons I am learning F#. I have read all the documentation that is available in the three published F# books and tried to build some simple parsers myself and downloaded the examples of Chris Smith.

This resulted in a naïve development approach: start with lexer, than create the parser, compose the AST and finally build your application that consumes the AST.

One of the lessons learned: when you want to create a parser you have to start with analyses of the text type. In case you can step through the text and can determine the action after each token a lexer is what you need. In case the action is determined by server tokens you need a parser.

Example of program that needs a lexer:

  • A program that replacing digits by roman numerals.
  • A simple encryptor

Example of program that needs a lexer and a parser:

  • Xml-parser
  • Code

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