TclTk 1

1
Tcl/Tk 1

• CS 414, Software Engineering I
• Mark Ardis
• Rose-Hulman Institute
• December 3, 2002

2
Outline

• Install Tcl/Tk
• Run some demos
• Create some simple widgets

3
Install Tcl/Tk

• Follow the instructions on the handout to copy
  and install Tcl/Tk
• Run some demo programs
• Start/Programs/ActiveState ActiveTcl
  8.4.1.0/ Demos/Tk
• Check out the documentation
• ActiveTcl8.4.1.0-html/index.html
• Right click on Package Documentation to Open in
  New Window

4
start.tcl

• Follow the instructions on the handout to copy
  start.tcl
• Double-click start.tcl
• Close start.tcl
• Open start.tcl with WordPad (or Notepad)

5
Variables in Tcl

• Use set for assignment
• set foo 123
• set tw .top
• Use for reference
• set bar foo
• toplevel tw

6
Widgets in Tk
.

• Widget names follow a hierarchy

top
.top.2.b4
2
b1
b2
b3
b4
7
frame and pack

• Use frame to create a logical group of widgets
• Use pack to display a widget
• frame tw.2
• pack tw.2

8
button

• The button command creates a button
• button tw.2.b1
• Attributes may be specified when creating the
  widget or later with configure
• button tw.2.b1 -text "7" -command "Digit 7"
• or
• tw.2.b1 configure -text "7" -command "Digit 7"

9
foreach

• foreach takes 3 arguments
• a loop variable
• a list of items to assign to the loop variable
• a block of code
• The block of code is executed once for each item
  in the list

10
foreach example

• foreach col 1 2 3 4
• pack tw.row.bcol
• is the same as
• pack tw.row.b1
• pack tw.row.b2
• pack tw.row.b3
• pack tw.row.b4

11
proc

• proc foo bar
• global baz
• set baz bar
• proc Digit arg
• DisplayMe arg

The global variablebaz needs to bedeclared
inside foo
12
Finishing the lab

• Add more buttons
• Add a label widget for a display
• Change DisplayMe to update the label you just
  created