Assignment

1
TCL

• Assignment 11
• Pete Moore
• COSC 4153
• Spring 2008

2
Overview

• History
• Syntax
• Features
• Example Code
• Language Use
• Advantages and Disadvantages
• Likes and Dislikes

3
History

• John Ousterhout
• Integrated Circuit Design at Berkely
• Poor Command Languages for tools
• Embeddable command language
• Extensions could control the application
• Tool Command Language
• Tk GUI's becoming popular and expensive
• 1989 he gave a talk about it word spread
• Sun
• Source kept free
• Many improvements
• Scriptics TCL Core Team

4
Syntax and Semantics

• Command argument argument ...
• Command command argument
• Symbols
• -- variable substitution
• argv0 could be replaced by /usr/bin/script.tcl
• -- subcommand substitution
• pwd might be replaced by /home/moorep
• "" -- word grouping with substitutions
• "you are user" is one word user is replaced
• word grouping without substitutions
• you are user is one word, but user is not
  replaced

5
more Syntax and Semantics

• More symbols
• \ -- backslash substitution/escape
• by default, statement ends with the line
• -- comment
• -- statement separator
• Command1 arg command2 arg
• -- namespace path separator
• (e.g. foobar)?
• No static typing
• variable can contain integers, floats, strings,
  lists or whatever
• Assignment is made with set
• set someVar value

6
Features

• C
• stdin, stdout, stderr
• argv
• for loop, while
• if, switch
• fopen, fputs, fgets, fclose, ftell (no f)?
• sprintf is format
• expr syntax (infix operators, functions,
  parens..)?
• Awk/Snobol
• associative arrays

7
Example Source Code

• Associative array stuff

• set capital(India) Delhi
• set capital(France) Paris
• set capital(Italy) Rome
• set capital(Germany) Berlin
• set capital(Poland) Warsaw
• set capital(Russia) Moscow
• puts capital(Italy)?
• lsort array names capital

8
More Source Code

• Proc

proc sum arg1 arg2 set x expr arg1
arg2 return x puts " The sum of 2 3
is sum 2 3\n\n

• C\TuxRacer Code.tcl

9
Language Use

• TuxRacer
• Web Applications
• Huge database backed sites like, AOLserver
• Can also be used as a conventional web language
• Desktop GUI Applications
• Dynamic approach fit's GUI's better than
  low-level C and C toolkits
• Testing and Automation
• Embedded Development
• Cisco
• Dominates EDA and CAD

10
Advantages and Disadvantages

• Disadvantages
• You might not know it yet
• Advantages
• Can embed and build on anything on it
• Comes with Tk

11
Likes and Dislikes

• Dislikes
• Wide use makes it daunting at first
• Wide amount of commands is also scary
• Likes
• Syntax looks very simple
• Typing looks very friendly
• Note
• How I encountered TCL

12
Conclusion

• History made John Ousterhout
• Embeddable can be made to do many things
• Tk good for GUI's
• Tuxracer apparently works for 3d games

13
Bibliography

• http//www.tcl.tk/
• http//www.tcl.tk/about/history.html
• http//wiki.tcl.tk/
• http//en.wikipedia.org/wiki/Tcl