Fruit basket program in F#
- From: Jamal Mazrui <empower@xxxxxxxxx>
- To: programmingblind@xxxxxxxxxxxxx
- Date: Wed, 03 Mar 2010 20:17:04 -0500
From the archive at
http://EmpowermentZone.com/fs_fruit.zip
This fruit basket program is written in F# (pronounced F Sharp). After
several years as a Microsoft research project, F# is becoming a first
class language for the .NET platform. It primarily implements a
functional style of programming, which tends to be well-suited for
scientific and parallel computing. Unlike other functional languages,
F# also supports imperative and object oriented styles.
F# development is supported in Visual Studio, though not currently in an
Express Edition. A command-line compiler is also available, as well as
an interactive environment for testing code, similar to that of Python
or Ruby.
By default, indentation is required in F#, similar to Python. This is
called the "light" syntax. An alternate syntax, similar to the ML
language, is also possible, where keywords or punctuation marks are used
to denote code blocks instead of indentation. I found that syntax hard
to do with the current compiler, however, because such error messages
are less helpful -- probably because the compiler has been tested far
less in this way.
Various F# resources are available at
http://FSharp.net
I have also collected text tutorials at
http://EmpowermentZone.com/fnetdoc.zip
Once the F# development kit is installed, the source code fs_fruit.fs,
also pasted below, may be compiled to fs_fruit.exe via the batch file
compile.bat. Since F# related assemblies are not installed with
versions of the .NET Framework below 4.0, they either have to be
distributed with an F# program as separate files, or built into the same
executable with the --standalone compiler option. I used this option,
resulting in an executable size of nearly a megabyte. By comparison,
the version with dependencies is about 10K.
Jamal
// Uncomment the following line for syntax that does not require indentation
//# indent "off"
(*
content of fs_fruit.fs
Fruit Basket program in F#
Public domain by Jamal Mazrui
*)
// Import namespaces
open System
open System.Windows.Forms
// Create controls
let tlp = new TableLayoutPanel(ColumnCount = 3, RowCount = 2)
let lblFruit = new Label(Text = "&Fruit:", Parent = tlp)
let txtFruit = new TextBox(Parent = tlp)
let btnAdd = new Button(Text = "&Add", Parent = tlp)
let lblBasket = new Label(Text = "&Basket:", Parent = tlp)
let lstBasket = new ListBox(Parent = tlp)
let btnDelete = new Button(Text = "&Delete", Parent = tlp)
// Define Add event handler
btnAdd.Click.Add(fun o ->
let sFruit = txtFruit.Text
if sFruit = "" then
ignore(MessageBox.Show("No fruit to add!"), "Alert")
else
txtFruit.Clear()
let iIndex = lstBasket.Items.Add(sFruit)
lstBasket.SelectedIndex <- iIndex)
// Define Delete event handler
btnDelete.Click.Add(fun o ->
let iIndex = lstBasket.SelectedIndex
if iIndex = -1 then
ignore(MessageBox.Show("No fruit to delete."), "Alert")
else
lstBasket.Items.RemoveAt(iIndex)
if iIndex = lstBasket.Items.Count then lstBasket.SelectedIndex
<- iIndex - 1
else lstBasket.SelectedIndex <- iIndex)
// Finalize dialog
let dlg = new Form(Text = "Fruit Basket", AcceptButton = btnAdd,
StartPosition = FormStartPosition.CenterScreen, AutoSize = true,
AutoSizeMode = AutoSizeMode.GrowAndShrink)
dlg.Controls.Add(tlp)
ignore(dlg.ShowDialog())
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